From f9113194aff4a08b6b7a73541993e05b520cd7f6 Mon Sep 17 00:00:00 2001
From: Andres AG <andres.amayagarcia@arm.com>
Date: Fri, 2 Sep 2016 14:06:04 +0100
Subject: [PATCH] Allow the entry_name size to be set in config.h

Allow the size of the entry_name character array in x509_crt.c to be
configurable through a macro in config.h. entry_name holds a
path/filename string. The macro introduced in
MBEDTLS_X509_MAX_FILE_PATH_LEN.
---
 ChangeLog                  |  3 +++
 include/mbedtls/config.h   |  1 +
 include/mbedtls/x509_crt.h |  4 ++++
 library/x509_crt.c         | 17 ++++++++++++-----
 4 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 6d7f1c25f..a4f98ceb5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,9 @@ Features
      is functioning correctly.
    * Added a script to print build environment info for diagnostic use in test
      scripts, which is also now called by all.sh.
+   * Added the macro MBEDTLS_X509_MAX_FILE_PATH_LEN that enables the user to
+     configure the maximum length of a file path that can be buffered when
+     calling mbedtls_x509_crt_parse_path().
 
 Bugfix
    * Fix for platform time abstraction to avoid dependency issues where a build
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 456ec667d..8d7d63110 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2569,6 +2569,7 @@
 
 /* X509 options */
 //#define MBEDTLS_X509_MAX_INTERMEDIATE_CA   8   /**< Maximum number of intermediate CAs in a verification chain. */
+//#define MBEDTLS_X509_MAX_FILE_PATH_LEN     512 /**< Maximum length of a path/filename string in bytes including the null terminator character ('\0'). */
 
 /* \} name SECTION: Customisation configuration options */
 
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index 41b6bfe57..383e484f7 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -120,6 +120,10 @@ mbedtls_x509_crt_profile;
 #define MBEDTLS_X509_RFC5280_MAX_SERIAL_LEN 32
 #define MBEDTLS_X509_RFC5280_UTC_TIME_LEN   15
 
+#if !defined( MBEDTLS_X509_MAX_FILE_PATH_LEN )
+#define MBEDTLS_X509_MAX_FILE_PATH_LEN 512
+#endif
+
 /**
  * Container for writing a certificate (CRT)
  */
diff --git a/library/x509_crt.c b/library/x509_crt.c
index af6c2a4a5..60e14f90e 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -1160,9 +1160,10 @@ int mbedtls_x509_crt_parse_path( mbedtls_x509_crt *chain, const char *path )
     FindClose( hFind );
 #else /* _WIN32 */
     int t_ret;
+    int snp_ret;
     struct stat sb;
     struct dirent *entry;
-    char entry_name[255];
+    char entry_name[MBEDTLS_X509_MAX_FILE_PATH_LEN];
     DIR *dir = opendir( path );
 
     if( dir == NULL )
@@ -1178,11 +1179,16 @@ int mbedtls_x509_crt_parse_path( mbedtls_x509_crt *chain, const char *path )
 
     while( ( entry = readdir( dir ) ) != NULL )
     {
-        mbedtls_snprintf( entry_name, sizeof entry_name, "%s/%s", path, entry->d_name );
+        snp_ret = mbedtls_snprintf( entry_name, sizeof entry_name,
+                                    "%s/%s", path, entry->d_name );
 
-        if( stat( entry_name, &sb ) == -1 )
+        if( snp_ret < 0 || (size_t)snp_ret >= sizeof entry_name )
+        {
+            ret = MBEDTLS_ERR_X509_BUFFER_TOO_SMALL;
+            goto cleanup;
+        }
+        else if( stat( entry_name, &sb ) == -1 )
         {
-            closedir( dir );
             ret = MBEDTLS_ERR_X509_FILE_IO_ERROR;
             goto cleanup;
         }
@@ -1198,9 +1204,10 @@ int mbedtls_x509_crt_parse_path( mbedtls_x509_crt *chain, const char *path )
         else
             ret += t_ret;
     }
-    closedir( dir );
 
 cleanup:
+    closedir( dir );
+
 #if defined(MBEDTLS_THREADING_PTHREAD)
     if( mbedtls_mutex_unlock( &mbedtls_threading_readdir_mutex ) != 0 )
         ret = MBEDTLS_ERR_THREADING_MUTEX_ERROR;