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| author | Nicolai Stange <nicstange@gmail.com> | 2016-03-20 23:23:46 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-20 15:41:52 +0900 |
| commit | 19c1764a19cdb41afebc2e66d7a75a7064c0000f (patch) | |
| tree | b249003ed109ce8c407bcd082524eedcdb23a4b1 /crypto | |
| parent | 63c22e8fe29efe1d03980d5cf933c4d7b9a72d09 (diff) | |
| download | lwn-19c1764a19cdb41afebc2e66d7a75a7064c0000f.tar.gz lwn-19c1764a19cdb41afebc2e66d7a75a7064c0000f.zip | |
PKCS#7: pkcs7_validate_trust(): initialize the _trusted output argument
commit e54358915d0a00399c11c2c23ae1be674cba188a upstream.
Despite what the DocBook comment to pkcs7_validate_trust() says, the
*_trusted argument is never set to false.
pkcs7_validate_trust() only positively sets *_trusted upon encountering
a trusted PKCS#7 SignedInfo block.
This is quite unfortunate since its callers, system_verify_data() for
example, depend on pkcs7_validate_trust() clearing *_trusted on non-trust.
Indeed, UBSAN splats when attempting to load the uninitialized local
variable 'trusted' from system_verify_data() in pkcs7_validate_trust():
UBSAN: Undefined behaviour in crypto/asymmetric_keys/pkcs7_trust.c:194:14
load of value 82 is not a valid value for type '_Bool'
[...]
Call Trace:
[<ffffffff818c4d35>] dump_stack+0xbc/0x117
[<ffffffff818c4c79>] ? _atomic_dec_and_lock+0x169/0x169
[<ffffffff8194113b>] ubsan_epilogue+0xd/0x4e
[<ffffffff819419fa>] __ubsan_handle_load_invalid_value+0x111/0x158
[<ffffffff819418e9>] ? val_to_string.constprop.12+0xcf/0xcf
[<ffffffff818334a4>] ? x509_request_asymmetric_key+0x114/0x370
[<ffffffff814b83f0>] ? kfree+0x220/0x370
[<ffffffff818312c2>] ? public_key_verify_signature_2+0x32/0x50
[<ffffffff81835e04>] pkcs7_validate_trust+0x524/0x5f0
[<ffffffff813c391a>] system_verify_data+0xca/0x170
[<ffffffff813c3850>] ? top_trace_array+0x9b/0x9b
[<ffffffff81510b29>] ? __vfs_read+0x279/0x3d0
[<ffffffff8129372f>] mod_verify_sig+0x1ff/0x290
[...]
The implication is that pkcs7_validate_trust() effectively grants trust
when it really shouldn't have.
Fix this by explicitly setting *_trusted to false at the very beginning
of pkcs7_validate_trust().
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/asymmetric_keys/pkcs7_trust.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c index 90d6d47965b0..ecdb5a2ce085 100644 --- a/crypto/asymmetric_keys/pkcs7_trust.c +++ b/crypto/asymmetric_keys/pkcs7_trust.c @@ -178,6 +178,8 @@ int pkcs7_validate_trust(struct pkcs7_message *pkcs7, int cached_ret = -ENOKEY; int ret; + *_trusted = false; + for (p = pkcs7->certs; p; p = p->next) p->seen = false; |