use-after-free in skcipher_sock_destruct

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello,

The following program triggers use-after-free in skcipher_sock_destruct:

// autogenerated by syzkaller (http://github.com/google/syzkaller)
#include <syscall.h>
#include <string.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <pthread.h>

struct sockaddr_alg {
        unsigned short   salg_family;
        char    salg_type[14];
        unsigned   salg_feat;
        unsigned   salg_mask;
        char    salg_name[64];
};

int fd;

void *thr0(void *arg)
{
        struct sockaddr_alg sa = {};
        sa.salg_family = 0x26;
        memcpy(sa.salg_type,
"\x73\x6b\x63\x69\x70\x68\x65\x72\x00\x00\x00\x00\x00\x00", 14);
        sa.salg_feat = 0xf;
        sa.salg_mask = 0x100;
        memcpy(sa.salg_name,
"\x65\x63\x62\x28\x73\x65\x72\x70\x65\x6e\x74\x29\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
64);
        bind(fd, (struct sockaddr*)&sa, sizeof(sa));
        return 0;
}

void *thr1(void *arg)
{
        accept4(fd, 0, 0, 0x800ul);
        return 0;
}

int main()
{
        fd = socket(PF_ALG, SOCK_SEQPACKET, 0);
        pthread_t th[4];
        pthread_create(&th[0], 0, thr0, 0);
        pthread_create(&th[1], 0, thr1, 0);
        pthread_create(&th[2], 0, thr0, 0);
        pthread_create(&th[3], 0, thr1, 0);
        pthread_join(th[0], 0);
        pthread_join(th[1], 0);
        pthread_join(th[2], 0);
        pthread_join(th[3], 0);
        return 0;
}


==================================================================
BUG: KASAN: use-after-free in skcipher_sock_destruct+0x39c/0x3e0 at
addr ffff8800387a2d38
Read of size 4 by task executor/27423
=============================================================================
BUG kmalloc-96 (Not tainted): kasan: bad access detected
-----------------------------------------------------------------------------

Disabling lock debugging due to kernel taint
INFO: Allocated in __crypto_alloc_tfm+0xd9/0x470 age=36 cpu=0 pid=27396
[<      none      >] __kmalloc+0x2d9/0x480 mm/slub.c:3532
[<     inline     >] kmalloc include/linux/slab.h:463
[<     inline     >] kzalloc include/linux/slab.h:602
[<      none      >] __crypto_alloc_tfm+0xd9/0x470 crypto/api.c:374
[<      none      >] crypto_alloc_ablkcipher+0x7b/0x1f0 crypto/ablkcipher.c:699
[<      none      >] skcipher_bind+0x25/0x30 crypto/algif_skcipher.c:754
[<      none      >] alg_bind+0x1a9/0x410 crypto/af_alg.c:155
[<      none      >] SYSC_bind+0x20a/0x2c0 net/socket.c:1383
[<      none      >] SyS_bind+0x24/0x30 net/socket.c:1369
[<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
arch/x86/entry/entry_64.S:185

INFO: Freed in kzfree+0x28/0x30 age=26 cpu=2 pid=27421
[<      none      >] kfree+0x26f/0x3e0 mm/slub.c:3632
[<      none      >] kzfree+0x28/0x30 mm/slab_common.c:1270
[<      none      >] crypto_destroy_tfm+0xdd/0x1e0 crypto/api.c:596
[<     inline     >] crypto_free_tfm include/linux/crypto.h:623
[<     inline     >] crypto_free_ablkcipher include/linux/crypto.h:769
[<      none      >] skcipher_release+0x18/0x20 crypto/algif_skcipher.c:759
[<     inline     >] alg_do_release crypto/af_alg.c:116
[<      none      >] alg_bind+0x26a/0x410 crypto/af_alg.c:170
[<      none      >] SYSC_bind+0x20a/0x2c0 net/socket.c:1383
[<      none      >] SyS_bind+0x24/0x30 net/socket.c:1369
[<      none      >] entry_SYSCALL_64_fastpath+0x16/0x7a
arch/x86/entry/entry_64.S:185

INFO: Slab 0xffffea0000e1e880 objects=19 used=8 fp=0xffff8800387a3380
flags=0x1fffc0000004080
INFO: Object 0xffff8800387a2d00 @offset=3328 fp=0xffff8800387a3520
CPU: 0 PID: 27423 Comm: executor Tainted: G    B           4.4.0-rc3+ #151
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
 0000000000000000 ffff880035c67700 ffffffff82e0f4b8 0000000041b58ab3
 ffffffff87a9a265 ffffffff82e0f406 ffff880037f15a00 ffffffff87abb3aa
 ffff88003e804780 0000000000000008 ffff8800387a2d00 ffff880035c67700

Call Trace:
 [<ffffffff81845754>] __asan_report_load4_noabort+0x54/0x70
mm/kasan/report.c:294
 [<     inline     >] crypto_ablkcipher_ivsize include/linux/crypto.h:807
 [<ffffffff82d2d3bc>] skcipher_sock_destruct+0x39c/0x3e0
crypto/algif_skcipher.c:787
 [<ffffffff856c9255>] sk_destruct+0xa5/0x5f0 net/core/sock.c:1446
 [<ffffffff856c982c>] __sk_free+0x8c/0x260 net/core/sock.c:1474
 [<ffffffff856c9a30>] sk_free+0x30/0x40 net/core/sock.c:1485
 [<     inline     >] sock_put include/net/sock.h:1625
 [<ffffffff82d26c50>] af_alg_release+0x60/0x90 crypto/af_alg.c:123
 [<ffffffff856b06b6>] sock_release+0x96/0x260 net/socket.c:571
 [<ffffffff856b0896>] sock_close+0x16/0x20 net/socket.c:1022
 [<ffffffff8189d9e4>] __fput+0x244/0x860 fs/file_table.c:208
 [<ffffffff8189e095>] ____fput+0x15/0x20 fs/file_table.c:244
 [<ffffffff813e34d0>] task_work_run+0x130/0x240 kernel/task_work.c:115
 [<     inline     >] exit_task_work include/linux/task_work.h:21
 [<ffffffff8137d8f5>] do_exit+0x885/0x3050 kernel/exit.c:750
 [<ffffffff8138021c>] do_group_exit+0xec/0x390 kernel/exit.c:880
 [<ffffffff813ab067>] get_signal+0x677/0x1bf0 kernel/signal.c:2307
 [<ffffffff8118645e>] do_signal+0x7e/0x2170 arch/x86/kernel/signal.c:709
 [<ffffffff81003a1e>] exit_to_usermode_loop+0xfe/0x1e0
arch/x86/entry/common.c:247
 [<     inline     >] prepare_exit_to_usermode arch/x86/entry/common.c:282
 [<ffffffff8100733b>] syscall_return_slowpath+0x16b/0x240
arch/x86/entry/common.c:344
 [<ffffffff86a8a122>] int_ret_from_sys_call+0x25/0x9f
arch/x86/entry/entry_64.S:281
==================================================================

On upstream commit 31ade3b83e1821da5fbb2f11b5b3d4ab2ec39db8 (Nov 29).
--
To unsubscribe from this list: send the line "unsubscribe linux-crypto" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Kernel]     [Gnu Classpath]     [Gnu Crypto]     [DM Crypt]     [Netfilter]     [Bugtraq]

  Powered by Linux