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authorEric Biggers <ebiggers@google.com>2018-02-22 14:38:33 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-28 10:19:39 +0100
commitdcb04cc794835964c1efeea24b392e5e35e88ab8 (patch)
tree157bd3dc8cecb90ae071ca48576724a1f55f9d40
parentfa465cd5681334cc7db63c9da999dcbb0137fb8c (diff)
X.509: fix BUG_ON() when hash algorithm is unsupported
commit 437499eea4291ae9621e8763a41df027c110a1ef upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--crypto/asymmetric_keys/public_key.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c
index 3cd6e12cfc46..d1af69d2ff85 100644
--- a/crypto/asymmetric_keys/public_key.c
+++ b/crypto/asymmetric_keys/public_key.c
@@ -93,9 +93,11 @@ 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