Fix OOB reads and infinite loop in TLV and DMAP parsers

pair_ap/pair-tlv.c (pair_tlv_parse):
- Add bounds check before reading type and length bytes (i + 2 > length)
- Fix off-by-one in chunked TLV scan loop (j + 1 < length)
- Add bounds checks inside data copy loop to prevent OOB memcpy
- Add else branch to advance index when size == 0 (prevents infinite loop)

rtsp.c (handle_set_parameter_metadata):
- Require 8 bytes remaining for tag + length fields (off + 8 <= cl)
- Validate value length against remaining buffer before read

Reported-by: Tristan Madani <tristan@talencesecurity.com>
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>

pair_ap/pair-tlv.c

@@ -162,18 +162,21 @@ pair_tlv_parse(const uint8_t *buffer, size_t length, pair_tlv_values_t *values)
     size_t i = 0;
     int ret;
     while (i < length) {
+        if (i + 2 > length)
+            return PAIR_TLV_ERROR_INSUFFICIENT_SIZE;
+
         uint8_t type = buffer[i];
         size_t size = 0;
         uint8_t *data = NULL;
 
         // scan TLVs to accumulate total size of subsequent TLVs with same type (chunked data)
         size_t j = i;
-        while (j < length && buffer[j] == type && buffer[j+1] == 255) {
+        while (j + 1 < length && buffer[j] == type && buffer[j+1] == 255) {
             size_t chunk_size = buffer[j+1];
             size += chunk_size;
             j += chunk_size + 2;
         }
-        if (j < length && buffer[j] == type) {
+        if (j + 1 < length && buffer[j] == type) {
             size_t chunk_size = buffer[j+1];
             size += chunk_size;
         }
@@ -188,12 +191,22 @@ pair_tlv_parse(const uint8_t *buffer, size_t length, pair_tlv_values_t *values)
 
             size_t remaining = size;
             while (remaining) {
+                if (i + 2 > length) {
+                    free(data);
+                    return PAIR_TLV_ERROR_INSUFFICIENT_SIZE;
+                }
                 size_t chunk_size = buffer[i+1];
+                if (chunk_size > length - i - 2) {
+                    free(data);
+                    return PAIR_TLV_ERROR_INSUFFICIENT_SIZE;
+                }
                 memcpy(p, &buffer[i+2], chunk_size);
                 p += chunk_size;
                 i += chunk_size + 2;
                 remaining -= chunk_size;
             }
+        } else {
+            i += 2;
         }
 
         ret = tlv_add_value_(values, type, data, size);

rtsp.c

@@ -3275,7 +3275,7 @@ static void handle_set_parameter_metadata(__attribute__((unused)) rtsp_conn_info
   unsigned int off = 8;
 
   uint32_t itag, vl;
-  while (off < cl) {
+  while (off + 8 <= cl) {
     // pick up the metadata tag as an unsigned longint
     memcpy(&itag, (uint32_t *)(cp + off), sizeof(uint32_t)); /* can be misaligned, thus memcpy */
     itag = ntohl(itag);
@@ -3286,6 +3286,9 @@ static void handle_set_parameter_metadata(__attribute__((unused)) rtsp_conn_info
     vl = ntohl(vl);
     off += sizeof(uint32_t);
 
+    if (vl > cl - off)
+      break;
+
     // pass the data over
     if (vl == 0)
       send_metadata('core', itag, NULL, 0, NULL, 1);