[PATCH AUTOSEL 5.4 5/6] verify_pefile: relax wrapper length check

[PATCH AUTOSEL 5.4 5/6] verify_pefile: relax wrapper length check

[Sasha Levin]

From: Robbie Harwood <rharwood@redhat.com>

[ 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@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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 crypto/asymmetric_keys/verify_pefile.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c
index cc9dbcecaacaa..c43b077ba37db 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) {
-- 
2.39.2

[PATCH AUTOSEL 5.4 6/6] asymmetric_keys: log on fatal failures in PE/pkcs7

[Sasha Levin]

From: Robbie Harwood <rharwood@redhat.com>

[ Upstream commit 3584c1dbfffdabf8e3dc1dd25748bb38dd01cd43 ]

These particular errors can be encountered while trying to kexec when
secureboot lockdown is in place.  Without this change, even with a
signed debug build, one still needs to reboot the machine to add the
appropriate dyndbg parameters (since lockdown blocks debugfs).

Accordingly, upgrade all pr_debug() before fatal error into pr_warn().

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://lore.kernel.org/r/20230220171254.592347-3-rharwood@redhat.com/ # v2
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 crypto/asymmetric_keys/pkcs7_verify.c  | 10 +++++-----
 crypto/asymmetric_keys/verify_pefile.c | 24 ++++++++++++------------
 2 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index ce49820caa97f..01e54450c846f 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -79,16 +79,16 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
 		}
 
 		if (sinfo->msgdigest_len != sig->digest_size) {
-			pr_debug("Sig %u: Invalid digest size (%u)\n",
-				 sinfo->index, sinfo->msgdigest_len);
+			pr_warn("Sig %u: Invalid digest size (%u)\n",
+				sinfo->index, sinfo->msgdigest_len);
 			ret = -EBADMSG;
 			goto error;
 		}
 
 		if (memcmp(sig->digest, sinfo->msgdigest,
 			   sinfo->msgdigest_len) != 0) {
-			pr_debug("Sig %u: Message digest doesn't match\n",
-				 sinfo->index);
+			pr_warn("Sig %u: Message digest doesn't match\n",
+				sinfo->index);
 			ret = -EKEYREJECTED;
 			goto error;
 		}
@@ -488,7 +488,7 @@ int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7,
 			       const void *data, size_t datalen)
 {
 	if (pkcs7->data) {
-		pr_debug("Data already supplied\n");
+		pr_warn("Data already supplied\n");
 		return -EINVAL;
 	}
 	pkcs7->data = data;
diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c
index c43b077ba37db..0701bb161b63f 100644
--- a/crypto/asymmetric_keys/verify_pefile.c
+++ b/crypto/asymmetric_keys/verify_pefile.c
@@ -74,7 +74,7 @@ static int pefile_parse_binary(const void *pebuf, unsigned int pelen,
 		break;
 
 	default:
-		pr_debug("Unknown PEOPT magic = %04hx\n", pe32->magic);
+		pr_warn("Unknown PEOPT magic = %04hx\n", pe32->magic);
 		return -ELIBBAD;
 	}
 
@@ -95,7 +95,7 @@ static int pefile_parse_binary(const void *pebuf, unsigned int pelen,
 	ctx->certs_size = ddir->certs.size;
 
 	if (!ddir->certs.virtual_address || !ddir->certs.size) {
-		pr_debug("Unsigned PE binary\n");
+		pr_warn("Unsigned PE binary\n");
 		return -ENODATA;
 	}
 
@@ -127,7 +127,7 @@ static int pefile_strip_sig_wrapper(const void *pebuf,
 	unsigned len;
 
 	if (ctx->sig_len < sizeof(wrapper)) {
-		pr_debug("Signature wrapper too short\n");
+		pr_warn("Signature wrapper too short\n");
 		return -ELIBBAD;
 	}
 
@@ -142,16 +142,16 @@ static int pefile_strip_sig_wrapper(const void *pebuf,
 	 * rounded up since 0.110.
 	 */
 	if (wrapper.length > ctx->sig_len) {
-		pr_debug("Signature wrapper bigger than sig len (%x > %x)\n",
-			 ctx->sig_len, wrapper.length);
+		pr_warn("Signature wrapper bigger than sig len (%x > %x)\n",
+			ctx->sig_len, wrapper.length);
 		return -ELIBBAD;
 	}
 	if (wrapper.revision != WIN_CERT_REVISION_2_0) {
-		pr_debug("Signature is not revision 2.0\n");
+		pr_warn("Signature is not revision 2.0\n");
 		return -ENOTSUPP;
 	}
 	if (wrapper.cert_type != WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
-		pr_debug("Signature certificate type is not PKCS\n");
+		pr_warn("Signature certificate type is not PKCS\n");
 		return -ENOTSUPP;
 	}
 
@@ -164,7 +164,7 @@ static int pefile_strip_sig_wrapper(const void *pebuf,
 	ctx->sig_offset += sizeof(wrapper);
 	ctx->sig_len -= sizeof(wrapper);
 	if (ctx->sig_len < 4) {
-		pr_debug("Signature data missing\n");
+		pr_warn("Signature data missing\n");
 		return -EKEYREJECTED;
 	}
 
@@ -198,7 +198,7 @@ static int pefile_strip_sig_wrapper(const void *pebuf,
 		return 0;
 	}
 not_pkcs7:
-	pr_debug("Signature data not PKCS#7\n");
+	pr_warn("Signature data not PKCS#7\n");
 	return -ELIBBAD;
 }
 
@@ -341,8 +341,8 @@ static int pefile_digest_pe(const void *pebuf, unsigned int pelen,
 	digest_size = crypto_shash_digestsize(tfm);
 
 	if (digest_size != ctx->digest_len) {
-		pr_debug("Digest size mismatch (%zx != %x)\n",
-			 digest_size, ctx->digest_len);
+		pr_warn("Digest size mismatch (%zx != %x)\n",
+			digest_size, ctx->digest_len);
 		ret = -EBADMSG;
 		goto error_no_desc;
 	}
@@ -373,7 +373,7 @@ static int pefile_digest_pe(const void *pebuf, unsigned int pelen,
 	 * PKCS#7 certificate.
 	 */
 	if (memcmp(digest, ctx->digest, ctx->digest_len) != 0) {
-		pr_debug("Digest mismatch\n");
+		pr_warn("Digest mismatch\n");
 		ret = -EKEYREJECTED;
 	} else {
 		pr_debug("The digests match!\n");
-- 
2.39.2