Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 11/54] X.509: fix BUG_ON() when hash algorithm is unsupported | Date | Mon, 26 Feb 2018 21:21:48 +0100 |
| |
4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Biggers <ebiggers@google.com>
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>
--- crypto/asymmetric_keys/public_key.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/crypto/asymmetric_keys/public_key.c +++ b/crypto/asymmetric_keys/public_key.c @@ -93,9 +93,11 @@ int public_key_verify_signature(const st 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
| |