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authorEric Biggers <ebiggers@google.com>2017-12-08 15:13:27 +0000
committerDavid Howells <dhowells@redhat.com>2017-12-08 15:13:27 +0000
commit81a7be2cd69b412ab6aeacfe5ebf1bb6e5bce955 (patch)
treeb1857871d87c93b0134c9f3bdb8ff92fe097030f /lib
parente0058f3a874ebb48b25be7ff79bc3b4e59929f90 (diff)
download96b-common-81a7be2cd69b412ab6aeacfe5ebf1bb6e5bce955.tar.gz
ASN.1: check for error from ASN1_OP_END__ACT actions
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>
Diffstat (limited to 'lib')
-rw-r--r--lib/asn1_decoder.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c
index d77cdfc4b554..dc14beae2c9a 100644
--- a/lib/asn1_decoder.c
+++ b/lib/asn1_decoder.c
@@ -439,6 +439,8 @@ next_op:
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;