From: Eric Biggers ebiggers@google.com
This patch has been added to the stable tree. If you have any objections, please let us know.
===============
[ Upstream commit 81a7be2cd69b412ab6aeacfe5ebf1bb6e5bce955 ]
asn1_ber_decoder() was ignoring errors from actions associated with the opcodes ASN1_OP_END_SEQ_ACT, ASN1_OP_END_SET_ACT, ASN1_OP_END_SEQ_OF_ACT, and ASN1_OP_END_SET_OF_ACT. In practice, this meant the pkcs7_note_signed_info() action (since that was the only user of those opcodes). Fix it by checking for the error, just like the decoder does for actions associated with the other opcodes.
This bug allowed users to leak slab memory by repeatedly trying to add a specially crafted "pkcs7_test" key (requires CONFIG_PKCS7_TEST_KEY).
In theory, this bug could also be used to bypass module signature verification, by providing a PKCS#7 message that is misparsed such that a signature's ->authattrs do not contain its ->msgdigest. But it doesn't seem practical in normal cases, due to restrictions on the format of the ->authattrs.
Fixes: 42d5ec27f873 ("X.509: Add an ASN.1 decoder") Cc: stable@vger.kernel.org # v3.7+ Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: David Howells dhowells@redhat.com Reviewed-by: James Morris james.l.morris@oracle.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- lib/asn1_decoder.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c index 3bb040e347ec..bbdfbcb912f3 100644 --- a/lib/asn1_decoder.c +++ b/lib/asn1_decoder.c @@ -421,6 +421,8 @@ int asn1_ber_decoder(const struct asn1_decoder *decoder, else act = machine[pc + 1]; ret = actions[act](context, hdr, 0, data + tdp, len); + if (ret < 0) + return ret; } pc += asn1_op_lengths[op]; goto next_op;