pkcs7: Drop support for signature in contentInfo of signed data
The contentInfo field of PKCS7 Signed Data structures can
optionally contain the content of the signature. Per RFC 2315
it can also contain any of the PKCS7 data types. Add test and
comments making it clear that the current implementation
only supports the DATA content type and the data must be empty.
Return codes should be clear whether content was invalid or
unsupported.
Identification and fix provided by:
- Demi Marie Obenour <demiobenour@gmail.com>
- Dave Rodgman <dave.rodgman@arm.com>
Signed-off-by: Nick Child <nick.child@ibm.com>
diff --git a/include/mbedtls/pkcs7.h b/include/mbedtls/pkcs7.h
index 82f282b..5ddd5a3 100644
--- a/include/mbedtls/pkcs7.h
+++ b/include/mbedtls/pkcs7.h
@@ -46,6 +46,8 @@
* - The RFC allows for SignerInfo structure to optionally contain
* unauthenticatedAttributes and authenticatedAttributes. In Mbed TLS it is
* assumed these fields are empty.
+ * - The RFC allows for the signed Data type to contain contentInfo. This
+ * implementation assumes the type is DATA and the content is empty.
*/
#ifndef MBEDTLS_PKCS7_H
diff --git a/library/pkcs7.c b/library/pkcs7.c
index 273842b..1159b9b 100644
--- a/library/pkcs7.c
+++ b/library/pkcs7.c
@@ -495,8 +495,18 @@
return ret;
}
- if (end_content_info != p) {
- return MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO;
+ if (p != end_content_info) {
+ /* Determine if valid content is present */
+ ret = mbedtls_asn1_get_tag(&p, end_content_info, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC);
+ if (ret != 0) {
+ return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, ret);
+ }
+ p += len;
+ if (p != end_content_info) {
+ return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, ret);
+ }
+ /* Valid content is present - this is not supported */
+ return MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE;
}
if (MBEDTLS_OID_CMP(MBEDTLS_OID_PKCS7_DATA, &signed_data->content.oid)) {
diff --git a/tests/data_files/Makefile b/tests/data_files/Makefile
index 14c1744..7121b5b 100644
--- a/tests/data_files/Makefile
+++ b/tests/data_files/Makefile
@@ -1202,6 +1202,11 @@
$(OPENSSL) smime -sign -binary -in pkcs7_data.bin -out $@ -md sha256 -signer pkcs7-rsa-sha256-1.pem -nocerts -noattr -outform DER -out $@
all_final += pkcs7_data_without_cert_signed.der
+# pkcs7 signature file with signature
+pkcs7_data_with_signature.der: $(pkcs7_test_file) $(pkcs7_test_cert_1)
+ $(OPENSSL) smime -sign -binary -in pkcs7_data.bin -out $@ -md sha256 -signer pkcs7-rsa-sha256-1.pem -nocerts -noattr -nodetach -outform DER -out $@
+all_final += pkcs7_data_with_signature.der
+
# pkcs7 signature file with two signers
pkcs7_data_multiple_signed.der: $(pkcs7_test_file) $(pkcs7_test_cert_1) $(pkcs7_test_cert_2)
$(OPENSSL) smime -sign -binary -in pkcs7_data.bin -out $@ -md sha256 -signer pkcs7-rsa-sha256-1.pem -signer pkcs7-rsa-sha256-2.pem -nocerts -noattr -outform DER -out $@
diff --git a/tests/data_files/pkcs7_data_with_signature.der b/tests/data_files/pkcs7_data_with_signature.der
new file mode 100644
index 0000000..cb9d126
--- /dev/null
+++ b/tests/data_files/pkcs7_data_with_signature.der
Binary files differ
diff --git a/tests/suites/test_suite_pkcs7.data b/tests/suites/test_suite_pkcs7.data
index 1319d7b..840a24b 100644
--- a/tests/suites/test_suite_pkcs7.data
+++ b/tests/suites/test_suite_pkcs7.data
@@ -22,6 +22,10 @@
depends_on:MBEDTLS_RSA_C:!MBEDTLS_SHA512_C
pkcs7_parse:"data_files/pkcs7_data_cert_signed_sha512.der":MBEDTLS_ERR_PKCS7_INVALID_ALG
+PKCS7 Parse Fail with Inlined Content Info #5.2
+depends_on:MBEDTLS_SHA256_C:MBEDTLS_RSA_C
+pkcs7_parse:"data_files/pkcs7_data_with_signature.der":MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE
+
PKCS7 Signed Data Parse Fail with corrupted signer info #6
depends_on:MBEDTLS_SHA256_C:MBEDTLS_RSA_C
pkcs7_parse:"data_files/pkcs7_data_signed_badsigner.der":MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO,MBEDTLS_ERR_ASN1_UNEXPECTED_TAG)
@@ -68,11 +72,11 @@
pkcs7_get_signers_info_set error handling (6213931373035520)
depends_on:MBEDTLS_RIPEMD160_C
-pkcs7_parse:"data_files/pkcs7_get_signers_info_set-missing_free-fuzz_pkcs7-6213931373035520.der":MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO
+pkcs7_parse:"data_files/pkcs7_get_signers_info_set-missing_free-fuzz_pkcs7-6213931373035520.der":MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, MBEDTLS_ERR_ASN1_UNEXPECTED_TAG)
pkcs7_get_signers_info_set error handling (4541044530479104)
depends_on:MBEDTLS_RIPEMD160_C
-pkcs7_parse:"data_files/pkcs7_get_signers_info_set-leak-fuzz_pkcs7-4541044530479104.der":MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO
+pkcs7_parse:"data_files/pkcs7_get_signers_info_set-leak-fuzz_pkcs7-4541044530479104.der": MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, MBEDTLS_ERR_ASN1_UNEXPECTED_TAG)
PKCS7 Only Signed Data Parse Pass #15
depends_on:MBEDTLS_SHA256_C:MBEDTLS_RSA_C