commit e97dc60b42481b77dbb2f1ae2fdae4a22fc385c1
author Gilles Peskine <Gilles.Peskine@arm.com> Wed Dec 19 00:51:38 2018 +0100
committer Gilles Peskine <Gilles.Peskine@arm.com> Wed Dec 19 00:55:36 2018 +0100
tree 4524cfcb48728b1cf248d25f885738c05f89ecf7
parent a310b41ebecf9724934666941df6d29ae2cbe8c2

Implement parameter validation in pk, pkparse and pkwrite

Add checks for null pointers under MBEDTLS_CHECK_PARAMS.

In functions that perform operations with a context, only check if the
context pointer is non-null under MBEDTLS_CHECK_PARAMS. In the default
configuration, unconditionally dereference the context pointer.

In functions that query a context, support NULL as a
pointer-to-context argument, and return the same value as for a
context which has been initialized but not set up.

library/pkparse.c

diff --git a/library/pkparse.c b/library/pkparse.c
index 86d9fb0..7c14e34 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -61,6 +61,12 @@
 #define mbedtls_free       free
 #endif
 
+/* Parameter validation macros based on platform_util.h */
+#define PK_VALIDATE_RET( cond )    \
+    MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_PK_BAD_INPUT_DATA )
+#define PK_VALIDATE( cond )        \
+    MBEDTLS_INTERNAL_VALIDATE( cond )
+
 #if defined(MBEDTLS_FS_IO)
 /*
  * Load all data from a file into a given buffer.
@@ -74,6 +80,10 @@
     FILE *f;
     long size;
 
+    PK_VALIDATE_RET( path != NULL );
+    PK_VALIDATE_RET( buf != NULL );
+    PK_VALIDATE_RET( n != NULL );
+
     if( ( f = fopen( path, "rb" ) ) == NULL )
         return( MBEDTLS_ERR_PK_FILE_IO_ERROR );
 
@@ -124,6 +134,8 @@
     size_t n;
     unsigned char *buf;
 
+    PK_VALIDATE_RET( ctx != NULL );
+
     if( ( ret = mbedtls_pk_load_file( path, &buf, &n ) ) != 0 )
         return( ret );
 
@@ -148,6 +160,8 @@
     size_t n;
     unsigned char *buf;
 
+    PK_VALIDATE_RET( ctx != NULL );
+
     if( ( ret = mbedtls_pk_load_file( path, &buf, &n ) ) != 0 )
         return( ret );
 
@@ -605,6 +619,11 @@
     mbedtls_pk_type_t pk_alg = MBEDTLS_PK_NONE;
     const mbedtls_pk_info_t *pk_info;
 
+    PK_VALIDATE_RET( p != NULL );
+    PK_VALIDATE_RET( *p != NULL );
+    PK_VALIDATE_RET( end != NULL );
+    PK_VALIDATE_RET( pk != NULL );
+
     if( ( ret = mbedtls_asn1_get_tag( p, end, &len,
                     MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
     {
@@ -1145,12 +1164,17 @@
 {
     int ret;
     const mbedtls_pk_info_t *pk_info;
-
 #if defined(MBEDTLS_PEM_PARSE_C)
     size_t len;
     mbedtls_pem_context pem;
+#endif
 
-    mbedtls_pem_init( &pem );
+    PK_VALIDATE_RET( pk != NULL );
+    PK_VALIDATE_RET( key != NULL || keylen == 0 );
+    PK_VALIDATE_RET( pwd != NULL || pwdlen == 0 );
+
+#if defined(MBEDTLS_PEM_PARSE_C)
+   mbedtls_pem_init( &pem );
 
 #if defined(MBEDTLS_RSA_C)
     /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
@@ -1360,7 +1384,12 @@
 #if defined(MBEDTLS_PEM_PARSE_C)
     size_t len;
     mbedtls_pem_context pem;
+#endif
 
+    PK_VALIDATE_RET( ctx != NULL );
+    PK_VALIDATE_RET( key != NULL || keylen == 0 );
+
+#if defined(MBEDTLS_PEM_PARSE_C)
     mbedtls_pem_init( &pem );
 #if defined(MBEDTLS_RSA_C)
     /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */