commit 673a226698e1b268fbda06235c04618c9d94a5a1
author Nayna Jain <nayna@linux.ibm.com> Mon Dec 14 22:44:49 2020 +0000
committer Nick Child <nick.child@ibm.com> Thu Sep 01 19:45:41 2022 -0500
tree fa0f5141a6573006e0000900964333075057510b
parent c9deb184b0bf5e72d5761d06af0db165676e0f8a

pkcs7: add support for signed data

OpenSSL provides APIs to generate only the signted data
format PKCS7 i.e. without content type OID. This patch
adds support to parse the data correctly even if formatted
only as signed data

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>

library/pkcs7.c

diff --git a/library/pkcs7.c b/library/pkcs7.c
index c3236e1..5563f33 100644
--- a/library/pkcs7.c
+++ b/library/pkcs7.c
@@ -103,6 +103,7 @@
 {
     size_t len = 0;
     int ret;
+    unsigned char *start = *p;
 
     ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
                                             | MBEDTLS_ASN1_SEQUENCE );
@@ -110,8 +111,10 @@
         return( MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO + ret );
 
     ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_OID );
-    if( ret != 0 )
+    if( ret != 0 ) {
+        *p = start;
         return( MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO + ret );
+    }
 
     pkcs7->tag = MBEDTLS_ASN1_OID;
     pkcs7->len = len;
@@ -428,6 +431,7 @@
     unsigned char *end;
     size_t len = 0;
     int ret;
+    int isoidset = 0;
 
     if( !pkcs7 )
         return( MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA );
@@ -444,7 +448,10 @@
 
     ret = pkcs7_get_content_info_type( &start, end, &pkcs7->content_type_oid );
     if( ret != 0 )
-        goto out;
+    {
+        len = buflen;
+        goto try_data;
+    }
 
     if( ! MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_DATA, &pkcs7->content_type_oid )
      || ! MBEDTLS_OID_CMP( MBEDTLS_OID_PKCS7_ENCRYPTED_DATA, &pkcs7->content_type_oid )
@@ -463,17 +470,31 @@
         goto out;
     }
 
+    isoidset = 1;
     start = start + pkcs7->content_type_oid.len;
 
     ret = pkcs7_get_next_content_len( &start, end, &len );
     if( ret != 0 )
         goto out;
 
+try_data:
     ret = pkcs7_get_signed_data( start, len, &pkcs7->signed_data );
+    if ( ret != 0 )
+        goto out;
+
+    if ( !isoidset )
+    {
+        pkcs7->content_type_oid.tag = MBEDTLS_ASN1_OID;
+        pkcs7->content_type_oid.len = MBEDTLS_OID_SIZE( MBEDTLS_OID_PKCS7_SIGNED_DATA );
+        pkcs7->content_type_oid.p = (unsigned char *)MBEDTLS_OID_PKCS7_SIGNED_DATA;
+    }
+
+    ret = MBEDTLS_PKCS7_SIGNED_DATA;
 
 out:
-    if ( ret != 0 )
+    if ( ret < 0 )
         mbedtls_pkcs7_free( pkcs7 );
+
     return( ret );
 }