commit c448c94fe3253ca8a2c2951b3ce1ecb03053c351
author Nick Child <nick.child@ibm.com> Thu Jul 01 15:29:50 2021 -0400
committer Nick Child <nick.child@ibm.com> Thu Sep 01 19:45:41 2022 -0500
tree 75d34ab168bfc16573ec27548324275ce4192fc8
parent 136c6aa46732ad0fd6d1f884af8eae8893208cbe

pkcs7: pkcs7_get_content_info_type should reset *p on error

The function `pkcs7_asn1_get_tag` should return an update pointer only
on success. Currently, the pointer is being updated on a failure case.
This commit resets *p to start if the first call to
mbedtls_asn1_get_tag fails.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Nick Child <nick.child@ibm.com>

library/pkcs7.c

diff --git a/library/pkcs7.c b/library/pkcs7.c
index 5563f33..8c2a3ec 100644
--- a/library/pkcs7.c
+++ b/library/pkcs7.c
@@ -107,8 +107,10 @@
 
     ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
                                             | MBEDTLS_ASN1_SEQUENCE );
-    if( ret != 0 )
+    if( ret != 0 ) {
+        *p = start;
         return( MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO + ret );
+    }
 
     ret = mbedtls_asn1_get_tag( p, end, &len, MBEDTLS_ASN1_OID );
     if( ret != 0 ) {