[FFmpeg-devel] [PATCH] avformat/mov: fix eof check after avio_skip()

[FFmpeg-devel] [PATCH] avformat/mov: fix eof check after avio_skip()

[Kacper Michajłow]

This fix ensures that the loop stops early on EOF. The issue occurs
because mov_read_infe() performs a version check and skips unsupported
versions. The problem is that seeking within the stream clears the EOF
flag, causing avio_feof() to not function as expected. This is resolved
by moving the EOF check after reading the size and type after seek,
ensuring the EOF flag is set when necessary.

Signed-off-by: Kacper Michajłow <kasper93@gmail.com>
---
 libavformat/mov.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 2c8be51063..9a388bf723 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -8868,12 +8868,12 @@ static int mov_read_iinf(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     for (i = 0; i < entry_count; i++) {
         MOVAtom infe;
 
+        infe.size = avio_rb32(pb) - 8;
+        infe.type = avio_rl32(pb);
         if (avio_feof(pb)) {
             ret = AVERROR_INVALIDDATA;
             goto fail;
         }
-        infe.size = avio_rb32(pb) - 8;
-        infe.type = avio_rl32(pb);
         ret = mov_read_infe(c, pb, infe, i);
         if (ret < 0)
             goto fail;
-- 
2.45.1

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Re: [FFmpeg-devel] [PATCH] avformat/mov: fix eof check after avio_skip()

[Kacper Michajlow]

On Mon, 3 Feb 2025 at 06:24, Kacper Michajłow <kasper93@gmail.com> wrote:
>
> This fix ensures that the loop stops early on EOF. The issue occurs
> because mov_read_infe() performs a version check and skips unsupported
> versions. The problem is that seeking within the stream clears the EOF
> flag, causing avio_feof() to not function as expected. This is resolved
> by moving the EOF check after reading the size and type after seek,
> ensuring the EOF flag is set when necessary.
>
> Signed-off-by: Kacper Michajłow <kasper93@gmail.com>
> ---
>  libavformat/mov.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index 2c8be51063..9a388bf723 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -8868,12 +8868,12 @@ static int mov_read_iinf(MOVContext *c, AVIOContext *pb, MOVAtom atom)
>      for (i = 0; i < entry_count; i++) {
>          MOVAtom infe;
>
> +        infe.size = avio_rb32(pb) - 8;
> +        infe.type = avio_rl32(pb);
>          if (avio_feof(pb)) {
>              ret = AVERROR_INVALIDDATA;
>              goto fail;
>          }
> -        infe.size = avio_rb32(pb) - 8;
> -        infe.type = avio_rl32(pb);
>          ret = mov_read_infe(c, pb, infe, i);
>          if (ret < 0)
>              goto fail;
> --
> 2.45.1
>

Sorry, sent the wrong patch, consider v2, with commit title fix.

- Kacper
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