[vlc-devel] [PATCH 2/2] include: strings: Add size check to vlc_hex_encode_binary

[Marvin Scholz]

---
 include/vlc_hash.h    | 16 ++++++++--------
 include/vlc_strings.h |  5 +++--
 src/text/strings.c    |  6 ++++--
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/include/vlc_hash.h b/include/vlc_hash.h
index 1e7757ac58..b5136677d2 100644
--- a/include/vlc_hash.h
+++ b/include/vlc_hash.h
@@ -57,14 +57,14 @@
  * \param[out]    output Output buffer to write the string to
  */
 #ifndef __cplusplus
-#define vlc_hash_FinishHex(ctx, output, size)                       \
-    do {                                                            \
-        char out_tmp[_Generic((ctx),                                \
-            vlc_hash_md5_t *: VLC_HASH_MD5_DIGEST_SIZE)];           \
-        _Generic((ctx),                                             \
-            vlc_hash_md5_t *: vlc_hash_md5_Finish)                  \
-        (ctx, out_tmp, sizeof(out_tmp));                            \
-        vlc_hex_encode_binary(out_tmp, sizeof(out_tmp), output);    \
+#define vlc_hash_FinishHex(ctx, output, size)                           \
+    do {                                                                \
+        char out_tmp[_Generic((ctx),                                    \
+            vlc_hash_md5_t *: VLC_HASH_MD5_DIGEST_SIZE)];               \
+        _Generic((ctx),                                                 \
+            vlc_hash_md5_t *: vlc_hash_md5_Finish)                      \
+        (ctx, out_tmp, sizeof(out_tmp));                                \
+        vlc_hex_encode_binary(out_tmp, sizeof(out_tmp), output, size);  \
     } while (0)
 #endif
 
diff --git a/include/vlc_strings.h b/include/vlc_strings.h
index 930d3347fb..5b4436141f 100644
--- a/include/vlc_strings.h
+++ b/include/vlc_strings.h
@@ -125,10 +125,11 @@ VLC_API char *vlc_xml_encode(const char *str) VLC_MALLOC;
  * string in hexadecimal representation.
  *
  * \param      input    Input buffer
- * \param      size     Input buffer size
+ * \param      in_size  Input buffer size
  * \param[out] output   Output buffer to write the string to
+ * \param      out_size Output buffer size
  */
-VLC_API void vlc_hex_encode_binary(const void *input, size_t size, char *output);
+VLC_API void vlc_hex_encode_binary(const void *input, size_t in_size, char *output, size_t out_size);
 
 /**
  * Base64 encoding.
diff --git a/src/text/strings.c b/src/text/strings.c
index 9676687aae..fc0babc7ce 100644
--- a/src/text/strings.c
+++ b/src/text/strings.c
@@ -347,11 +347,13 @@ char *vlc_xml_encode (const char *str)
 }
 
 /* Hex encoding */
-void vlc_hex_encode_binary(const void *input, size_t size, char *output)
+void vlc_hex_encode_binary(const void *input, size_t in_size,
+                           char *output, size_t out_size)
 {
+    assert(out_size >= in_size * 2 + 1); // 2 chars per byte + null
     const unsigned char *buffer = input;
 
-    for (size_t i = 0; i < size; i++) {
+    for (size_t i = 0; i < in_size; i++) {
         sprintf(&output[i * 2], "%02hhx", buffer[i]);
     }
 }
-- 
2.24.1 (Apple Git-126)