This is a note to let you know that I've just added the patch titled
verify_pefile: relax wrapper length check
to the 5.10-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:
verify_pefile-relax-wrapper-length-check.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 27b2dacdcf03da550f1b262507d0919da6ff1a07
Author: Robbie Harwood <rharwood@xxxxxxxxxx>
Date: Mon Feb 20 12:12:53 2023 -0500
verify_pefile: relax wrapper length check
[ Upstream commit 4fc5c74dde69a7eda172514aaeb5a7df3600adb3 ]
The PE Format Specification (section "The Attribute Certificate Table
(Image Only)") states that `dwLength` is to be rounded up to 8-byte
alignment when used for traversal. Therefore, the field is not required
to be an 8-byte multiple in the first place.
Accordingly, pesign has not performed this alignment since version
0.110. This causes kexec failure on pesign'd binaries with "PEFILE:
Signature wrapper len wrong". Update the comment and relax the check.
Signed-off-by: Robbie Harwood <rharwood@xxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
cc: keyrings@xxxxxxxxxxxxxxx
cc: linux-crypto@xxxxxxxxxxxxxxx
cc: kexec@xxxxxxxxxxxxxxxxxxx
Link: https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#the-attribute-certificate-table-image-only
Link: https://github.com/rhboot/pesign
Link: https://lore.kernel.org/r/20230220171254.592347-2-rharwood@xxxxxxxxxx/ # v2
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c
index 7553ab18db898..fe1bb374239d7 100644
--- a/crypto/asymmetric_keys/verify_pefile.c
+++ b/crypto/asymmetric_keys/verify_pefile.c
@@ -135,11 +135,15 @@ static int pefile_strip_sig_wrapper(const void *pebuf,
pr_debug("sig wrapper = { %x, %x, %x }\n",
wrapper.length, wrapper.revision, wrapper.cert_type);
- /* Both pesign and sbsign round up the length of certificate table
- * (in optional header data directories) to 8 byte alignment.
+ /* sbsign rounds up the length of certificate table (in optional
+ * header data directories) to 8 byte alignment. However, the PE
+ * specification states that while entries are 8-byte aligned, this is
+ * not included in their length, and as a result, pesign has not
+ * rounded up since 0.110.
*/
- if (round_up(wrapper.length, 8) != ctx->sig_len) {
- pr_debug("Signature wrapper len wrong\n");
+ if (wrapper.length > ctx->sig_len) {
+ pr_debug("Signature wrapper bigger than sig len (%x > %x)\n",
+ ctx->sig_len, wrapper.length);
return -ELIBBAD;
}
if (wrapper.revision != WIN_CERT_REVISION_2_0) {
