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| author | Eric Biggers <ebiggers@google.com> | 2018-02-22 14:38:33 +0000 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2018-02-22 14:38:33 +0000 |
| commit | 437499eea4291ae9621e8763a41df027c110a1ef (patch) | |
| tree | 93da0e30e6a005bd7dedd19b998ea1d81311dcb1 /crypto | |
| parent | 6459ae386699a5fe0dc52cf30255f75274fa43a4 (diff) | |
| download | lwn-437499eea4291ae9621e8763a41df027c110a1ef.tar.gz lwn-437499eea4291ae9621e8763a41df027c110a1ef.zip | |
X.509: fix BUG_ON() when hash algorithm is unsupported
The X.509 parser mishandles the case where the certificate's signature's
hash algorithm is not available in the crypto API. In this case,
x509_get_sig_params() doesn't allocate the cert->sig->digest buffer;
this part seems to be intentional. However,
public_key_verify_signature() is still called via
x509_check_for_self_signed(), which triggers the 'BUG_ON(!sig->digest)'.
Fix this by making public_key_verify_signature() return -ENOPKG if the
hash buffer has not been allocated.
Reproducer when all the CONFIG_CRYPTO_SHA512* options are disabled:
openssl req -new -sha512 -x509 -batch -nodes -outform der \
| keyctl padd asymmetric desc @s
Fixes: 6c2dc5ae4ab7 ("X.509: Extract signature digest and make self-signed cert checks earlier")
Reported-by: Paolo Valente <paolo.valente@linaro.org>
Cc: Paolo Valente <paolo.valente@linaro.org>
Cc: <stable@vger.kernel.org> # v4.7+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/asymmetric_keys/public_key.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c index de996586762a..e929fe1e4106 100644 --- a/crypto/asymmetric_keys/public_key.c +++ b/crypto/asymmetric_keys/public_key.c @@ -79,9 +79,11 @@ int public_key_verify_signature(const struct public_key *pkey, BUG_ON(!pkey); BUG_ON(!sig); - BUG_ON(!sig->digest); BUG_ON(!sig->s); + if (!sig->digest) + return -ENOPKG; + alg_name = sig->pkey_algo; if (strcmp(sig->pkey_algo, "rsa") == 0) { /* The data wangled by the RSA algorithm is typically padded |