This is a note to let you know that I've just added the patch titled ASN.1: check for error from ASN1_OP_END__ACT actions to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: asn.1-check-for-error-from-asn1_op_end__act-actions.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 81a7be2cd69b412ab6aeacfe5ebf1bb6e5bce955 Mon Sep 17 00:00:00 2001 From: Eric Biggers <ebiggers@xxxxxxxxxx> Date: Fri, 8 Dec 2017 15:13:27 +0000 Subject: ASN.1: check for error from ASN1_OP_END__ACT actions From: Eric Biggers <ebiggers@xxxxxxxxxx> commit 81a7be2cd69b412ab6aeacfe5ebf1bb6e5bce955 upstream. 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") Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Reviewed-by: James Morris <james.l.morris@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/asn1_decoder.c | 2 ++ 1 file changed, 2 insertions(+) --- a/lib/asn1_decoder.c +++ b/lib/asn1_decoder.c @@ -438,6 +438,8 @@ 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; Patches currently in stable-queue which might be from ebiggers@xxxxxxxxxx are queue-4.4/x.509-reject-invalid-bit-string-for-subjectpublickey.patch queue-4.4/asn.1-check-for-error-from-asn1_op_end__act-actions.patch queue-4.4/asn.1-fix-out-of-bounds-read-when-parsing-indefinite-length-item.patch