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| author | Eric Biggers <ebiggers@google.com> | 2017-06-08 16:48:47 +0300 |
|---|---|---|
| committer | James Morris <james.l.morris@oracle.com> | 2017-06-09 06:29:47 +0300 |
| commit | 63a0b0509e700717a59f049ec6e4e04e903c7fe2 (patch) | |
| tree | b333df2959fad9f119adb66f301ca2c76cf711c8 /security/keys/key.c | |
| parent | 5649645d725c73df4302428ee4e02c869248b4c5 (diff) | |
| download | linux-63a0b0509e700717a59f049ec6e4e04e903c7fe2.tar.xz | |
KEYS: fix freeing uninitialized memory in key_update()
key_update() freed the key_preparsed_payload even if it was not
initialized first. This would cause a crash if userspace called
keyctl_update() on a key with type like "asymmetric" that has a
->preparse() method but not an ->update() method. Possibly it could
even be triggered for other key types by racing with keyctl_setperm() to
make the KEY_NEED_WRITE check fail (the permission was already checked,
so normally it wouldn't fail there).
Reproducer with key type "asymmetric", given a valid cert.der:
keyctl new_session
keyid=$(keyctl padd asymmetric desc @s < cert.der)
keyctl setperm $keyid 0x3f000000
keyctl update $keyid data
[ 150.686666] BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
[ 150.687601] IP: asymmetric_key_free_kids+0x12/0x30
[ 150.688139] PGD 38a3d067
[ 150.688141] PUD 3b3de067
[ 150.688447] PMD 0
[ 150.688745]
[ 150.689160] Oops: 0000 [#1] SMP
[ 150.689455] Modules linked in:
[ 150.689769] CPU: 1 PID: 2478 Comm: keyctl Not tainted 4.11.0-rc4-xfstests-00187-ga9f6b6b8cd2f #742
[ 150.690916] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
[ 150.692199] task: ffff88003b30c480 task.stack: ffffc90000350000
[ 150.692952] RIP: 0010:asymmetric_key_free_kids+0x12/0x30
[ 150.693556] RSP: 0018:ffffc90000353e58 EFLAGS: 00010202
[ 150.694142] RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000004
[ 150.694845] RDX: ffffffff81ee3920 RSI: ffff88003d4b0700 RDI: 0000000000000001
[ 150.697569] RBP: ffffc90000353e60 R08: ffff88003d5d2140 R09: 0000000000000000
[ 150.702483] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[ 150.707393] R13: 0000000000000004 R14: ffff880038a4d2d8 R15: 000000000040411f
[ 150.709720] FS: 00007fcbcee35700(0000) GS:ffff88003fd00000(0000) knlGS:0000000000000000
[ 150.711504] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 150.712733] CR2: 0000000000000001 CR3: 0000000039eab000 CR4: 00000000003406e0
[ 150.714487] Call Trace:
[ 150.714975] asymmetric_key_free_preparse+0x2f/0x40
[ 150.715907] key_update+0xf7/0x140
[ 150.716560] ? key_default_cmp+0x20/0x20
[ 150.717319] keyctl_update_key+0xb0/0xe0
[ 150.718066] SyS_keyctl+0x109/0x130
[ 150.718663] entry_SYSCALL_64_fastpath+0x1f/0xc2
[ 150.719440] RIP: 0033:0x7fcbce75ff19
[ 150.719926] RSP: 002b:00007ffd5d167088 EFLAGS: 00000206 ORIG_RAX: 00000000000000fa
[ 150.720918] RAX: ffffffffffffffda RBX: 0000000000404d80 RCX: 00007fcbce75ff19
[ 150.721874] RDX: 00007ffd5d16785e RSI: 000000002866cd36 RDI: 0000000000000002
[ 150.722827] RBP: 0000000000000006 R08: 000000002866cd36 R09: 00007ffd5d16785e
[ 150.723781] R10: 0000000000000004 R11: 0000000000000206 R12: 0000000000404d80
[ 150.724650] R13: 00007ffd5d16784d R14: 00007ffd5d167238 R15: 000000000040411f
[ 150.725447] Code: 83 c4 08 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 85 ff 74 23 55 48 89 e5 53 48 89 fb <48> 8b 3f e8 06 21 c5 ff 48 8b 7b 08 e8 fd 20 c5 ff 48 89 df e8
[ 150.727489] RIP: asymmetric_key_free_kids+0x12/0x30 RSP: ffffc90000353e58
[ 150.728117] CR2: 0000000000000001
[ 150.728430] ---[ end trace f7f8fe1da2d5ae8d ]---
Fixes: 4d8c0250b841 ("KEYS: Call ->free_preparse() even after ->preparse() returns an error")
Cc: stable@vger.kernel.org # 3.17+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Diffstat (limited to 'security/keys/key.c')
| -rw-r--r-- | security/keys/key.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/security/keys/key.c b/security/keys/key.c index 455c04d80bbb..cbae368c0e57 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -966,12 +966,11 @@ int key_update(key_ref_t key_ref, const void *payload, size_t plen) /* the key must be writable */ ret = key_permission(key_ref, KEY_NEED_WRITE); if (ret < 0) - goto error; + return ret; /* attempt to update it if supported */ - ret = -EOPNOTSUPP; if (!key->type->update) - goto error; + return -EOPNOTSUPP; memset(&prep, 0, sizeof(prep)); prep.data = payload; |