[FFmpeg-devel] [PATCH v2] Fix sdp size check on fmtp integer parameters

[Olivier Maignial]

RFC-4566 do not give any limit of size on interger parameters given in fmtp line.
By reading some more RFCs it is possible to find examples where some integers parameters are greater than 32 (see RFC-6416, 7.4)

Instead I propose to check just check the eventual integer overflow.
Using INT_MIN and INT_MAX ensure that it will work whatever the size of int given by compiler

Signed-off-by: Olivier Maignial <olivier.maignial at smile.fr>
---

Changes v1 -> v2:
    - Removed line break at end of 'if' line before brace
    - Added Signed-Off-By line

 libavformat/rtpdec_mpeg4.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/libavformat/rtpdec_mpeg4.c b/libavformat/rtpdec_mpeg4.c
index 994ab49..14caa0a 100644
--- a/libavformat/rtpdec_mpeg4.c
+++ b/libavformat/rtpdec_mpeg4.c
@@ -289,15 +289,23 @@ static int parse_fmtp(AVFormatContext *s,
         for (i = 0; attr_names[i].str; ++i) {
             if (!av_strcasecmp(attr, attr_names[i].str)) {
                 if (attr_names[i].type == ATTR_NAME_TYPE_INT) {
-                    int val = atoi(value);
-                    if (val > 32) {
+                    char *end_ptr = NULL;
+                    long int val = strtol(value, &end_ptr, 10);
+                    if (value[0] == '\n' || end_ptr[0] != '\0') {
                         av_log(s, AV_LOG_ERROR,
-                               "The %s field size is invalid (%d)\n",
+                               "The %s field value is not a number (%s)\n",
+                               attr, value);
+                        return AVERROR_INVALIDDATA;
+                    }
+
+                    if (val > INT_MAX || val < INT_MIN) {
+                        av_log(s, AV_LOG_ERROR,
+                               "The %s field size is invalid (%ld)\n",
                                attr, val);
                         return AVERROR_INVALIDDATA;
                     }
                     *(int *)((char *)data+
-                        attr_names[i].offset) = val;
+                        attr_names[i].offset) = (int) val;
                 } else if (attr_names[i].type == ATTR_NAME_TYPE_STR) {
                     char *val = av_strdup(value);
                     if (!val)
-- 
2.7.4