// https://syzkaller.appspot.com/bug?id=80197ea80eb86971d149ca7de451613190556477 // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef __NR_memfd_create #define __NR_memfd_create 319 #endif static bool write_file(const char* file, const char* what, ...) { char buf[1024]; va_list args; va_start(args, what); vsnprintf(buf, sizeof(buf), what, args); va_end(args); buf[sizeof(buf) - 1] = 0; int len = strlen(buf); int fd = open(file, O_WRONLY | O_CLOEXEC); if (fd == -1) return false; if (write(fd, buf, len) != len) { int err = errno; close(fd); errno = err; return false; } close(fd); return true; } #define MAX_FDS 30 static void setup_gadgetfs(); static void setup_binderfs(); static void setup_fusectl(); static void sandbox_common_mount_tmpfs(void) { write_file("/proc/sys/fs/mount-max", "100000"); if (mkdir("./syz-tmp", 0777)) exit(1); if (mount("", "./syz-tmp", "tmpfs", 0, NULL)) exit(1); if (mkdir("./syz-tmp/newroot", 0777)) exit(1); if (mkdir("./syz-tmp/newroot/dev", 0700)) exit(1); unsigned bind_mount_flags = MS_BIND | MS_REC | MS_PRIVATE; if (mount("/dev", "./syz-tmp/newroot/dev", NULL, bind_mount_flags, NULL)) exit(1); if (mkdir("./syz-tmp/newroot/proc", 0700)) exit(1); if (mount("syz-proc", "./syz-tmp/newroot/proc", "proc", 0, NULL)) exit(1); if (mkdir("./syz-tmp/newroot/selinux", 0700)) exit(1); const char* selinux_path = "./syz-tmp/newroot/selinux"; if (mount("/selinux", selinux_path, NULL, bind_mount_flags, NULL)) { if (errno != ENOENT) exit(1); if (mount("/sys/fs/selinux", selinux_path, NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); } if (mkdir("./syz-tmp/newroot/sys", 0700)) exit(1); if (mount("/sys", "./syz-tmp/newroot/sys", 0, bind_mount_flags, NULL)) exit(1); if (mount("/sys/kernel/debug", "./syz-tmp/newroot/sys/kernel/debug", NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); if (mount("/sys/fs/smackfs", "./syz-tmp/newroot/sys/fs/smackfs", NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); if (mount("/proc/sys/fs/binfmt_misc", "./syz-tmp/newroot/proc/sys/fs/binfmt_misc", NULL, bind_mount_flags, NULL) && errno != ENOENT) exit(1); if (mkdir("./syz-tmp/newroot/syz-inputs", 0700)) exit(1); if (mount("/syz-inputs", "./syz-tmp/newroot/syz-inputs", NULL, bind_mount_flags | MS_RDONLY, NULL) && errno != ENOENT) exit(1); if (mkdir("./syz-tmp/pivot", 0777)) exit(1); if (syscall(SYS_pivot_root, "./syz-tmp", "./syz-tmp/pivot")) { if (chdir("./syz-tmp")) exit(1); } else { if (chdir("/")) exit(1); if (umount2("./pivot", MNT_DETACH)) exit(1); } if (chroot("./newroot")) exit(1); if (chdir("/")) exit(1); setup_gadgetfs(); setup_binderfs(); setup_fusectl(); } static void setup_gadgetfs() { if (mkdir("/dev/gadgetfs", 0777)) { } if (mount("gadgetfs", "/dev/gadgetfs", "gadgetfs", 0, NULL)) { } } static void setup_fusectl() { if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) { } } static void setup_binderfs() { if (mkdir("/dev/binderfs", 0777)) { } if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) { } if (symlink("/dev/binderfs", "./binderfs")) { } } static void loop(); static void sandbox_common() { prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0); if (getppid() == 1) exit(1); struct rlimit rlim; rlim.rlim_cur = rlim.rlim_max = (200 << 20); setrlimit(RLIMIT_AS, &rlim); rlim.rlim_cur = rlim.rlim_max = 32 << 20; setrlimit(RLIMIT_MEMLOCK, &rlim); rlim.rlim_cur = rlim.rlim_max = 136 << 20; setrlimit(RLIMIT_FSIZE, &rlim); rlim.rlim_cur = rlim.rlim_max = 1 << 20; setrlimit(RLIMIT_STACK, &rlim); rlim.rlim_cur = rlim.rlim_max = 128 << 20; setrlimit(RLIMIT_CORE, &rlim); rlim.rlim_cur = rlim.rlim_max = 256; setrlimit(RLIMIT_NOFILE, &rlim); if (unshare(CLONE_NEWNS)) { } if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) { } if (unshare(CLONE_NEWIPC)) { } if (unshare(0x02000000)) { } if (unshare(CLONE_NEWUTS)) { } if (unshare(CLONE_SYSVSEM)) { } typedef struct { const char* name; const char* value; } sysctl_t; static const sysctl_t sysctls[] = { {"/proc/sys/kernel/shmmax", "16777216"}, {"/proc/sys/kernel/shmall", "536870912"}, {"/proc/sys/kernel/shmmni", "1024"}, {"/proc/sys/kernel/msgmax", "8192"}, {"/proc/sys/kernel/msgmni", "1024"}, {"/proc/sys/kernel/msgmnb", "1024"}, {"/proc/sys/kernel/sem", "1024 1048576 500 1024"}, }; unsigned i; for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++) write_file(sysctls[i].name, sysctls[i].value); } static int wait_for_loop(int pid) { if (pid < 0) exit(1); int status = 0; while (waitpid(-1, &status, __WALL) != pid) { } return WEXITSTATUS(status); } static void drop_caps(void) { struct __user_cap_header_struct cap_hdr = {}; struct __user_cap_data_struct cap_data[2] = {}; cap_hdr.version = _LINUX_CAPABILITY_VERSION_3; cap_hdr.pid = getpid(); if (syscall(SYS_capget, &cap_hdr, &cap_data)) exit(1); const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE); cap_data[0].effective &= ~drop; cap_data[0].permitted &= ~drop; cap_data[0].inheritable &= ~drop; if (syscall(SYS_capset, &cap_hdr, &cap_data)) exit(1); } static int do_sandbox_none(void) { if (unshare(CLONE_NEWPID)) { } int pid = fork(); if (pid != 0) return wait_for_loop(pid); sandbox_common(); drop_caps(); if (unshare(CLONE_NEWNET)) { } write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535"); sandbox_common_mount_tmpfs(); loop(); exit(1); } static void close_fds() { for (int fd = 3; fd < MAX_FDS; fd++) close(fd); } uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0xffffffffffffffff}; void loop(void) { intptr_t res = 0; if (write(1, "executing program\n", sizeof("executing program\n") - 1)) { } // openat$udambuf arguments: [ // fd: const = 0xffffffffffffff9c (8 bytes) // file: ptr[in, buffer] { // buffer: {2f 64 65 76 2f 75 64 6d 61 62 75 66 00} (length 0xd) // } // flags: const = 0x2 (4 bytes) // ] // returns fd_udambuf memcpy((void*)0x200000000100, "/dev/udmabuf\000", 13); res = syscall(__NR_openat, /*fd=*/0xffffffffffffff9cul, /*file=*/0x200000000100ul, /*flags=*/2, 0); if (res != -1) r[0] = res; // memfd_create arguments: [ // name: ptr[in, buffer] { // buffer: {79 10 35 fb f7 75 83 25 3a 72 c2 b9 78 a4 71 c1 ea 5f 8c 5a // 37 e7 61 de 6e 4a eb 87 9b 11 78 0e a1 cf 1a 98 53 37 c9 00 00 00 00 // 00 00 07 00 00 00 00 00 00 04 87 39 a2 34 a9 61 6d de b2 d3 cb 5a 4a // 6f 61 c4 1a 63 42 aa c1 fb 20 51 d4 f4 01 a5 32 e2 44 47 d4 bd 7b 9f // a9 97 9b 40 db 00 62 e1 62 72 b6 00 38 e3 10 ff c2 9d 0d 32 9e 8e 04 // 73 57 1b b7 b3 a2 c9 26 40 ca da dc e2 2f 97 58 ac 08 b0 c2 3c 80 45 // 1a bc c7 57 da 39 56 73 41 af c6 cf e1 a1 b5 4d a2 85 a6 79 c4 4a f1 // f7 fc 44 95 e3 eb c7 bc 91 b0 a8 9e 6f eb 46 28 9d 4c 01 76 52 6b aa // 63 42 14 4f 44 5c e8 52 e4 cd ec cc d1 0f 72 65 e8 36 cd eb c4 24 98 // 06 4a d6 64 44 8d 5f 55 60 6a 69 7b ab 97 af 3b 6c 1f af b3 38 14 cb // fa b3 6a 92 0c e0 81 a0 a2 2d 67 08 99 0e 8d 8d 16 d9 77 5c f0 ce b0 // 6a 9d 27 93 ef 1d a0 48 d9 bd d9 af 12 00 00 00 00 00 00 00 00 00} // (length 0x110) // } // flags: memfd_flags = 0x2 (8 bytes) // ] // returns fd_memfd memcpy((void*)0x200000000340, "y\0205\373\367u\203%:r\302\271x\244q\301\352_" "\214Z7\347a\336nJ\353\207\233\021x\016\241\317\032\230S7\311\000\000" "\000\000\000\000\a\000\000\000\000\000\000\004\2079\2424\251am\336" "\262\323\313ZJoa\304\032cB\252\301\373 " "Q\324\364\001\2452\342DG\324\275{\237\251\227\233@" "\333\000b\341br\266\0008\343\020\377\302\235\r2\236\216\004sW\033\267" "\263\242\311&@\312\332\334\342/" "\227X\254\b\260\302<" "\200E\032\274\307W\3329VsA\257\306\317\341\241\265M\242\205\246y\304J" "\361\367\374D\225\343\353\307\274\221\260\250\236o\353F(" "\235L\001vRk\252cB\024OD\\\350R\344\315\354\314\321\017re\3506\315" "\353\304$\230\006J\326dD\215_U`ji{\253\227\257;" "l\037\257\2638\024\313\372\263j\222\f\340\201\240\242-" "g\b\231\016\215\215\026\331w\\\360\316\260j\235\'\223\357\035\240H" "\331\275\331\257\022\000\000\000\000\000\000\000\000\000", 272); res = syscall(__NR_memfd_create, /*name=*/0x200000000340ul, /*flags=MFD_ALLOW_SEALING*/ 2ul); if (res != -1) r[1] = res; // ftruncate arguments: [ // fd: fd (resource) // len: intptr = 0xffff (8 bytes) // ] syscall(__NR_ftruncate, /*fd=*/r[1], /*len=*/0xfffful); // fcntl$addseals arguments: [ // fd: fd (resource) // cmd: const = 0x409 (8 bytes) // seals: seal_types = 0x7 (8 bytes) // ] syscall(__NR_fcntl, /*fd=*/r[1], /*cmd=*/0x409ul, /*seals=F_SEAL_GROW|F_SEAL_SHRINK|F_SEAL_SEAL*/ 7ul); // ioctl$UDMABUF_CREATE arguments: [ // fd: fd_udambuf (resource) // cmd: const = 0x40187542 (4 bytes) // arg: ptr[in, udmabuf_create] { // udmabuf_create { // memfd: fd_memfd (resource) // flags: int32 = 0x1 (4 bytes) // offset: udmabuf_offset_size = 0x8000 (8 bytes) // size: udmabuf_offset_size = 0x4000 (8 bytes) // } // } // ] // returns fd_dma_buf *(uint32_t*)0x200000000140 = r[1]; *(uint32_t*)0x200000000144 = 1; *(uint64_t*)0x200000000148 = 0x8000; *(uint64_t*)0x200000000150 = 0x4000; res = syscall(__NR_ioctl, /*fd=*/r[0], /*cmd=*/0x40187542, /*arg=*/0x200000000140ul); if (res != -1) r[2] = res; // mmap arguments: [ // addr: VMA[0x3000] // len: len = 0x3000 (8 bytes) // prot: mmap_prot = 0x3000007 (8 bytes) // flags: mmap_flags = 0x11 (8 bytes) // fd: fd (resource) // offset: intptr = 0x0 (8 bytes) // ] syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0x3000ul, /*prot=PROT_GROWSUP|PROT_GROWSDOWN|PROT_WRITE|PROT_READ|PROT_EXEC*/ 0x3000007ul, /*flags=MAP_FIXED|MAP_SHARED*/ 0x11ul, /*fd=*/r[2], /*offset=*/0ul); // mincore arguments: [ // addr: VMA[0x800000] // size: len = 0x800000 (8 bytes) // vec: ptr[out, buffer] { // buffer: (DirOut) // } // ] syscall(__NR_mincore, /*addr=*/0x200000000000ul, /*size=*/0x800000ul, /*vec=*/0x200000000280ul); close_fds(); } int main(void) { syscall(__NR_mmap, /*addr=*/0x1ffffffff000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0x1000000ul, /*prot=PROT_WRITE|PROT_READ|PROT_EXEC*/ 7ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); syscall(__NR_mmap, /*addr=*/0x200001000000ul, /*len=*/0x1000ul, /*prot=*/0ul, /*flags=MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE*/ 0x32ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); const char* reason; (void)reason; do_sandbox_none(); return 0; }