diff options
| author | Robbie Harwood <rharwood@redhat.com> | 2023-02-20 12:12:53 -0500 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2023-03-21 16:23:17 +0000 |
| commit | 4fc5c74dde69a7eda172514aaeb5a7df3600adb3 (patch) | |
| tree | 0c27f9b2a14cba8719d2147b6ee116a948ac1ed5 /crypto | |
| parent | 47f9e4c924025c5be87959d3335e66fcbb7f6b5c (diff) | |
| download | lwn-4fc5c74dde69a7eda172514aaeb5a7df3600adb3.tar.gz lwn-4fc5c74dde69a7eda172514aaeb5a7df3600adb3.zip | |
verify_pefile: relax wrapper length check
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@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jarkko Sakkinen <jarkko@kernel.org>
cc: Eric Biederman <ebiederm@xmission.com>
cc: Herbert Xu <herbert@gondor.apana.org.au>
cc: keyrings@vger.kernel.org
cc: linux-crypto@vger.kernel.org
cc: kexec@lists.infradead.org
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@redhat.com/ # v2
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/asymmetric_keys/verify_pefile.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c index 7553ab18db89..fe1bb374239d 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) { |