// https://syzkaller.appspot.com/bug?id=0199fdfb23c7d9c82d5942dfc467f69e46cade43 // autogenerated by syzkaller (https://github.com/google/syzkaller) #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef __NR_io_uring_setup #define __NR_io_uring_setup 425 #endif static __thread int clone_ongoing; static __thread int skip_segv; static __thread jmp_buf segv_env; static void segv_handler(int sig, siginfo_t* info, void* ctx) { if (__atomic_load_n(&clone_ongoing, __ATOMIC_RELAXED) != 0) { exit(sig); } uintptr_t addr = (uintptr_t)info->si_addr; const uintptr_t prog_start = 1 << 20; const uintptr_t prog_end = 100 << 20; int skip = __atomic_load_n(&skip_segv, __ATOMIC_RELAXED) != 0; int valid = addr < prog_start || addr > prog_end; if (skip && valid) { _longjmp(segv_env, 1); } exit(sig); } static void install_segv_handler(void) { struct sigaction sa; memset(&sa, 0, sizeof(sa)); sa.sa_handler = SIG_IGN; syscall(SYS_rt_sigaction, 0x20, &sa, NULL, 8); syscall(SYS_rt_sigaction, 0x21, &sa, NULL, 8); memset(&sa, 0, sizeof(sa)); sa.sa_sigaction = segv_handler; sa.sa_flags = SA_NODEFER | SA_SIGINFO; sigaction(SIGSEGV, &sa, NULL); sigaction(SIGBUS, &sa, NULL); } #define NONFAILING(...) \ ({ \ int ok = 1; \ __atomic_fetch_add(&skip_segv, 1, __ATOMIC_SEQ_CST); \ if (_setjmp(segv_env) == 0) { \ __VA_ARGS__; \ } else \ ok = 0; \ __atomic_fetch_sub(&skip_segv, 1, __ATOMIC_SEQ_CST); \ ok; \ }) #define SIZEOF_IO_URING_SQE 64 #define SIZEOF_IO_URING_CQE 16 #define SQ_HEAD_OFFSET 0 #define SQ_TAIL_OFFSET 64 #define SQ_RING_MASK_OFFSET 256 #define SQ_RING_ENTRIES_OFFSET 264 #define SQ_FLAGS_OFFSET 276 #define SQ_DROPPED_OFFSET 272 #define CQ_HEAD_OFFSET 128 #define CQ_TAIL_OFFSET 192 #define CQ_RING_MASK_OFFSET 260 #define CQ_RING_ENTRIES_OFFSET 268 #define CQ_RING_OVERFLOW_OFFSET 284 #define CQ_FLAGS_OFFSET 280 #define CQ_CQES_OFFSET 320 struct io_sqring_offsets { uint32_t head; uint32_t tail; uint32_t ring_mask; uint32_t ring_entries; uint32_t flags; uint32_t dropped; uint32_t array; uint32_t resv1; uint64_t resv2; }; struct io_cqring_offsets { uint32_t head; uint32_t tail; uint32_t ring_mask; uint32_t ring_entries; uint32_t overflow; uint32_t cqes; uint64_t resv[2]; }; struct io_uring_params { uint32_t sq_entries; uint32_t cq_entries; uint32_t flags; uint32_t sq_thread_cpu; uint32_t sq_thread_idle; uint32_t features; uint32_t resv[4]; struct io_sqring_offsets sq_off; struct io_cqring_offsets cq_off; }; #define IORING_OFF_SQ_RING 0 #define IORING_OFF_SQES 0x10000000ULL #define IORING_SETUP_SQE128 (1U << 10) #define IORING_SETUP_CQE32 (1U << 11) static long syz_io_uring_setup(volatile long a0, volatile long a1, volatile long a2, volatile long a3) { uint32_t entries = (uint32_t)a0; struct io_uring_params* setup_params = (struct io_uring_params*)a1; void** ring_ptr_out = (void**)a2; void** sqes_ptr_out = (void**)a3; setup_params->flags &= ~(IORING_SETUP_CQE32 | IORING_SETUP_SQE128); uint32_t fd_io_uring = syscall(__NR_io_uring_setup, entries, setup_params); uint32_t sq_ring_sz = setup_params->sq_off.array + setup_params->sq_entries * sizeof(uint32_t); uint32_t cq_ring_sz = setup_params->cq_off.cqes + setup_params->cq_entries * SIZEOF_IO_URING_CQE; uint32_t ring_sz = sq_ring_sz > cq_ring_sz ? sq_ring_sz : cq_ring_sz; *ring_ptr_out = mmap(0, ring_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd_io_uring, IORING_OFF_SQ_RING); uint32_t sqes_sz = setup_params->sq_entries * SIZEOF_IO_URING_SQE; *sqes_ptr_out = mmap(0, sqes_sz, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd_io_uring, IORING_OFF_SQES); uint32_t* array = (uint32_t*)((uintptr_t)*ring_ptr_out + setup_params->sq_off.array); for (uint32_t index = 0; index < entries; index++) array[index] = index; return fd_io_uring; } static long syz_open_procfs(volatile long a0, volatile long a1) { char buf[128]; memset(buf, 0, sizeof(buf)); if (a0 == 0) { snprintf(buf, sizeof(buf), "/proc/self/%s", (char*)a1); } else if (a0 == -1) { snprintf(buf, sizeof(buf), "/proc/thread-self/%s", (char*)a1); } else { snprintf(buf, sizeof(buf), "/proc/self/task/%d/%s", (int)a0, (char*)a1); } int fd = open(buf, O_RDWR); if (fd == -1) fd = open(buf, O_RDONLY); return fd; } uint64_t r[1] = {0xffffffffffffffff}; 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; install_segv_handler(); intptr_t res = 0; if (write(1, "executing program\n", sizeof("executing program\n") - 1)) { } // mmap$IORING_OFF_SQ_RING arguments: [ // addr: VMA[0xc00000] // len: len = 0xc00000 (8 bytes) // prot: mmap_prot = 0x2000007 (8 bytes) // flags: mmap_flags = 0x401d031 (8 bytes) // fd: fd_io_uring (resource) // offset: const = 0x0 (8 bytes) // ] // returns ring_ptr syscall( __NR_mmap, /*addr=*/0x200000400000ul, /*len=*/0xc00000ul, /*prot=PROT_GROWSUP|PROT_WRITE|PROT_READ|PROT_EXEC*/ 0x2000007ul, /*flags=MAP_UNINITIALIZED|MAP_POPULATE|MAP_NORESERVE|MAP_NONBLOCK|MAP_FIXED|0x1021*/ 0x401d031ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); // mmap arguments: [ // addr: VMA[0xb36000] // len: len = 0xb36000 (8 bytes) // prot: mmap_prot = 0x2 (8 bytes) // flags: mmap_flags = 0x8031 (8 bytes) // fd: fd (resource) // offset: intptr = 0x0 (8 bytes) // ] syscall(__NR_mmap, /*addr=*/0x200000000000ul, /*len=*/0xb36000ul, /*prot=PROT_WRITE*/ 2ul, /*flags=MAP_POPULATE|MAP_FIXED|MAP_ANONYMOUS|MAP_SHARED*/ 0x8031ul, /*fd=*/(intptr_t)-1, /*offset=*/0ul); // syz_io_uring_setup arguments: [ // entries: int32 = 0x4175 (4 bytes) // params: ptr[inout, io_uring_params] { // io_uring_params { // sq_entries: int32 = 0x0 (4 bytes) // cq_entries: int32 = 0x136f (4 bytes) // flags: io_uring_setup_flags = 0x10000 (4 bytes) // sq_thread_cpu: int32 = 0x2 (4 bytes) // sq_thread_idle: int32 = 0x2d0 (4 bytes) // features: int32 = 0x0 (4 bytes) // wq_fd: fd_io_uring (resource) // resv: buffer: {00 00 00 00 00 00 00 00 00 00 00 00} (length 0xc) // sq_off: array[int32] { // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // } // cq_off: array[int32] { // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // int32 = 0x0 (4 bytes) // } // } // } // ring_ptr: nil // sqes_ptr: nil // ] // returns fd_io_uring NONFAILING(*(uint32_t*)0x200000000184 = 0x136f); NONFAILING(*(uint32_t*)0x200000000188 = 0x10000); NONFAILING(*(uint32_t*)0x20000000018c = 2); NONFAILING(*(uint32_t*)0x200000000190 = 0x2d0); NONFAILING(*(uint32_t*)0x200000000198 = -1); NONFAILING(memset((void*)0x20000000019c, 0, 12)); NONFAILING(syz_io_uring_setup(/*entries=*/0x4175, /*params=*/0x200000000180, /*ring_ptr=*/0, /*sqes_ptr=*/0)); // syz_open_procfs arguments: [ // pid: pid (resource) // file: ptr[in, buffer] { // buffer: {6d 61 70 73 00} (length 0x5) // } // ] // returns fd NONFAILING(memcpy((void*)0x2000000001c0, "maps\000", 5)); res = -1; NONFAILING(res = syz_open_procfs(/*pid=*/0, /*file=*/0x2000000001c0)); if (res != -1) r[0] = res; // ioctl$KVM_SET_USER_MEMORY_REGION arguments: [ // fd: fd_kvmvm (resource) // cmd: const = 0xc0686611 (4 bytes) // arg: ptr[in, kvm_userspace_memory_region] { // kvm_userspace_memory_region { // slot: kvm_mem_slots = 0x68 (4 bytes) // flags: kvm_mem_region_flags = 0x0 (4 bytes) // paddr: kvm_guest_addrs = 0x17 (8 bytes) // size: len = 0x2000 (8 bytes) // addr: VMA[0x2000] // } // } // ] NONFAILING(*(uint32_t*)0x200000000180 = 0x68); NONFAILING(*(uint32_t*)0x200000000184 = 0); NONFAILING(*(uint64_t*)0x200000000188 = 0x17); NONFAILING(*(uint64_t*)0x200000000190 = 0x2000); NONFAILING(*(uint64_t*)0x200000000198 = 0x200000ffd000); syscall(__NR_ioctl, /*fd=*/r[0], /*cmd=*/0xc0686611, /*arg=*/0x200000000180ul); return 0; }