[FFmpeg-cvslog] avformat/rtmppkt: Simplify and deobfuscate amf_tag_skip() slightly

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Fri Jun  7 23:05:47 2024 +0200| [cedbef03946625bc0f7f96e9f77ad59c512b9900] | committer: Michael Niedermayer

avformat/rtmppkt: Simplify and deobfuscate amf_tag_skip() slightly

Found while reviewing: CID1530313 Untrusted loop bound

Sponsored-by: Sovereign Tech Fund
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=cedbef03946625bc0f7f96e9f77ad59c512b9900
---

 libavformat/rtmppkt.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/libavformat/rtmppkt.c b/libavformat/rtmppkt.c
index bb7e6d20bc..ec10c89fc8 100644
--- a/libavformat/rtmppkt.c
+++ b/libavformat/rtmppkt.c
@@ -440,7 +440,6 @@ static int amf_tag_skip(GetByteContext *gb)
 {
     AMFDataType type;
     unsigned nb   = -1;
-    int parse_key = 1;
 
     if (bytestream2_get_bytes_left(gb) < 1)
         return -1;
@@ -465,13 +464,12 @@ static int amf_tag_skip(GetByteContext *gb)
         bytestream2_skip(gb, 10);
         return 0;
     case AMF_DATA_TYPE_ARRAY:
-        parse_key = 0;
     case AMF_DATA_TYPE_MIXEDARRAY:
         nb = bytestream2_get_be32(gb);
     case AMF_DATA_TYPE_OBJECT:
-        while (nb-- > 0 || type != AMF_DATA_TYPE_ARRAY) {
+        while (type != AMF_DATA_TYPE_ARRAY || nb-- > 0) {
             int t;
-            if (parse_key) {
+            if (type != AMF_DATA_TYPE_ARRAY) {
                 int size = bytestream2_get_be16(gb);
                 if (!size) {
                     bytestream2_get_byte(gb);