| From b4cdceb4ac50c249d096e10406fde92e9c52fcc4 Mon Sep 17 00:00:00 2001 |
| From: Nick Bowler <nbowler@elliptictech.com> |
| Date: Thu, 20 Oct 2011 14:16:55 +0200 |
| Subject: [PATCH] crypto: ghash - Avoid null pointer dereference if no key is |
| set |
| |
| commit 7ed47b7d142ec99ad6880bbbec51e9f12b3af74c upstream. |
| |
| The ghash_update function passes a pointer to gf128mul_4k_lle which will |
| be NULL if ghash_setkey is not called or if the most recent call to |
| ghash_setkey failed to allocate memory. This causes an oops. Fix this |
| up by returning an error code in the null case. |
| |
| This is trivially triggered from unprivileged userspace through the |
| AF_ALG interface by simply writing to the socket without setting a key. |
| |
| The ghash_final function has a similar issue, but triggering it requires |
| a memory allocation failure in ghash_setkey _after_ at least one |
| successful call to ghash_update. |
| |
| BUG: unable to handle kernel NULL pointer dereference at 00000670 |
| IP: [<d88c92d4>] gf128mul_4k_lle+0x23/0x60 [gf128mul] |
| *pde = 00000000 |
| Oops: 0000 [#1] PREEMPT SMP |
| Modules linked in: ghash_generic gf128mul algif_hash af_alg nfs lockd nfs_acl sunrpc bridge ipv6 stp llc |
| |
| Pid: 1502, comm: hashatron Tainted: G W 3.1.0-rc9-00085-ge9308cf #32 Bochs Bochs |
| EIP: 0060:[<d88c92d4>] EFLAGS: 00000202 CPU: 0 |
| EIP is at gf128mul_4k_lle+0x23/0x60 [gf128mul] |
| EAX: d69db1f0 EBX: d6b8ddac ECX: 00000004 EDX: 00000000 |
| ESI: 00000670 EDI: d6b8ddac EBP: d6b8ddc8 ESP: d6b8dda4 |
| DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 |
| Process hashatron (pid: 1502, ti=d6b8c000 task=d6810000 task.ti=d6b8c000) |
| Stack: |
| 00000000 d69db1f0 00000163 00000000 d6b8ddc8 c101a520 d69db1f0 d52aa000 |
| 00000ff0 d6b8dde8 d88d310f d6b8a3f8 d52aa000 00001000 d88d502c d6b8ddfc |
| 00001000 d6b8ddf4 c11676ed d69db1e8 d6b8de24 c11679ad d52aa000 00000000 |
| Call Trace: |
| [<c101a520>] ? kmap_atomic_prot+0x37/0xa6 |
| [<d88d310f>] ghash_update+0x85/0xbe [ghash_generic] |
| [<c11676ed>] crypto_shash_update+0x18/0x1b |
| [<c11679ad>] shash_ahash_update+0x22/0x36 |
| [<c11679cc>] shash_async_update+0xb/0xd |
| [<d88ce0ba>] hash_sendpage+0xba/0xf2 [algif_hash] |
| [<c121b24c>] kernel_sendpage+0x39/0x4e |
| [<d88ce000>] ? 0xd88cdfff |
| [<c121b298>] sock_sendpage+0x37/0x3e |
| [<c121b261>] ? kernel_sendpage+0x4e/0x4e |
| [<c10b4dbc>] pipe_to_sendpage+0x56/0x61 |
| [<c10b4e1f>] splice_from_pipe_feed+0x58/0xcd |
| [<c10b4d66>] ? splice_from_pipe_begin+0x10/0x10 |
| [<c10b51f5>] __splice_from_pipe+0x36/0x55 |
| [<c10b4d66>] ? splice_from_pipe_begin+0x10/0x10 |
| [<c10b6383>] splice_from_pipe+0x51/0x64 |
| [<c10b63c2>] ? default_file_splice_write+0x2c/0x2c |
| [<c10b63d5>] generic_splice_sendpage+0x13/0x15 |
| [<c10b4d66>] ? splice_from_pipe_begin+0x10/0x10 |
| [<c10b527f>] do_splice_from+0x5d/0x67 |
| [<c10b6865>] sys_splice+0x2bf/0x363 |
| [<c129373b>] ? sysenter_exit+0xf/0x16 |
| [<c104dc1e>] ? trace_hardirqs_on_caller+0x10e/0x13f |
| [<c129370c>] sysenter_do_call+0x12/0x32 |
| Code: 83 c4 0c 5b 5e 5f c9 c3 55 b9 04 00 00 00 89 e5 57 8d 7d e4 56 53 8d 5d e4 83 ec 18 89 45 e0 89 55 dc 0f b6 70 0f c1 e6 04 01 d6 <f3> a5 be 0f 00 00 00 4e 89 d8 e8 48 ff ff ff 8b 45 e0 89 da 0f |
| EIP: [<d88c92d4>] gf128mul_4k_lle+0x23/0x60 [gf128mul] SS:ESP 0068:d6b8dda4 |
| CR2: 0000000000000670 |
| ---[ end trace 4eaa2a86a8e2da24 ]--- |
| note: hashatron[1502] exited with preempt_count 1 |
| BUG: scheduling while atomic: hashatron/1502/0x10000002 |
| INFO: lockdep is turned off. |
| [...] |
| |
| Signed-off-by: Nick Bowler <nbowler@elliptictech.com> |
| Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| --- |
| crypto/ghash-generic.c | 6 ++++++ |
| 1 file changed, 6 insertions(+) |
| |
| diff --git a/crypto/ghash-generic.c b/crypto/ghash-generic.c |
| index be4425616931..7835b8fc94db 100644 |
| --- a/crypto/ghash-generic.c |
| +++ b/crypto/ghash-generic.c |
| @@ -67,6 +67,9 @@ static int ghash_update(struct shash_desc *desc, |
| struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm); |
| u8 *dst = dctx->buffer; |
| |
| + if (!ctx->gf128) |
| + return -ENOKEY; |
| + |
| if (dctx->bytes) { |
| int n = min(srclen, dctx->bytes); |
| u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes); |
| @@ -119,6 +122,9 @@ static int ghash_final(struct shash_desc *desc, u8 *dst) |
| struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm); |
| u8 *buf = dctx->buffer; |
| |
| + if (!ctx->gf128) |
| + return -ENOKEY; |
| + |
| ghash_flush(ctx, dctx); |
| memcpy(dst, buf, GHASH_BLOCK_SIZE); |
| |
| -- |
| 1.8.5.2 |
| |