[FFmpeg-devel] [PATCH v2 3/7] avformat/hlsenc: Check some unchecked allocations

[Andreas Rheinhardt]

Steven Liu:
> 
> 
>> 2020年5月8日 下午7:07，Andreas Rheinhardt <andreas.rheinhardt at gmail.com> 写道：
>>
>> Steven Liu:
>>>
>>>
>>>> 2020年4月9日 下午8:58，Andreas Rheinhardt <andreas.rheinhardt at gmail.com> 写道：
>>>>
>>>> Steven Liu:
>>>>>
>>>>>
>>>>>> 2020年4月9日 下午5:55，Steven Liu <lq at chinaffmpeg.org> 写道：
>>>>>>
>>>>>>
>>>>>>
>>>>>>> 2020年4月9日 下午5:48，Andreas Rheinhardt <andreas.rheinhardt at gmail.com> 写道：
>>>>>>>
>>>>>>> Steven Liu:
>>>>>>>>
>>>>>>>>
>>>>>>>>> 2020年2月28日 下午5:53，Andreas Rheinhardt <andreas.rheinhardt at gmail.com> 写道：
>>>>>>>>>
>>>>>>>>> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
>>>>>>>>> ---
>>>>>>>>> libavformat/hlsenc.c | 13 ++++++++++++-
>>>>>>>>> 1 file changed, 12 insertions(+), 1 deletion(-)
>>>>>>>>>
>>>>>>>>> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
>>>>>>>>> index a281c379f0..18f40ff3ed 100644
>>>>>>>>> --- a/libavformat/hlsenc.c
>>>>>>>>> +++ b/libavformat/hlsenc.c
>>>>>>>>> @@ -1610,6 +1610,8 @@ static int hls_start(AVFormatContext *s, VariantStream *vs)
>>>>>>>>>         if (c->use_localtime_mkdir) {
>>>>>>>>>             const char *dir;
>>>>>>>>>             char *fn_copy = av_strdup(oc->url);
>>>>>>>>> +                if (!fn_copy)
>>>>>>>>> +                    return AVERROR(ENOMEM);
>>>>>>>>>             dir = av_dirname(fn_copy);
>>>>>>>>>             if (ff_mkdir_p(dir) == -1 && errno != EEXIST) {
>>>>>>>>>                 av_log(oc, AV_LOG_ERROR, "Could not create directory %s with use_localtime_mkdir\n", dir);
>>>>>>>>> @@ -1770,6 +1772,8 @@ static int validate_name(int nb_vs, const char *fn)
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> fn_dup = av_strdup(fn);
>>>>>>>>> +    if (!fn_dup)
>>>>>>>>> +        return AVERROR(ENOMEM);
>>>>>>>>> filename = av_basename(fn);
>>>>>>>>> subdir_name = av_dirname(fn_dup);
>>>>>>>>>
>>>>>>>>> @@ -2139,6 +2143,8 @@ static int update_master_pl_info(AVFormatContext *s)
>>>>>>>>> int ret = 0;
>>>>>>>>>
>>>>>>>>> fn1 = av_strdup(s->url);
>>>>>>>>> +    if (!fn1)
>>>>>>>>> +        return AVERROR(ENOMEM);
>>>>>>>> It’s unnecessary here,
>>>>>>>> I have checked all strdup return checker in hlsenc some month ago, and double check the workflow in update_master_pl_info,
>>>>>>>> It's the safe whether you check the strdup or not.
>>>>>>>> Reference commit id: 61aa77272a25d83e5ce5c63d93c64bb9a3e15557
>>>>>>>
>>>>>>> If these strdups fail, the relevant dirnames will be wrong. While you
>>>>>>> don't get segfaults, you will not create the files at the right
>>>>>>> destinations. We should rather error out instead.
>>>>>>>
>>>>>> Maybe need reproduce the problem it let me understand the exception.
>>>>>> I need one example, command line is ok.
>>>>>>
>>>>>>
>>>>> I accept the 61aa77272a2 because i don’t know how to reproduce the exception to objection it. I have no example to objection it.
>>>>>
>>>> Command line:
>>>> ffmpeg -i <Input file> -c copy -t 1:30 -f hls -hls_time 2
>>>> -hls_playlist_type event -master_pl_name index.m3u8
>>>> -hls_segment_filename stream_%v/data%06d.ts   -use_localtime_mkdir 1
>>>> -var_stream_map 'v:0,a:0' test/test%v/stream.m3u8
>>>> (My input file simply had H.264 video and AC-3 audio, but I don't think
>>>> that is important.)
>>>>
>>>> If I run this normally, I get two subfolders in the current directory:
>>>> stream_0 and test. stream_0 contains various transport streams, test
>>>> contains index.m3u8 and a folder test0 which contains stream.m3u8.
>>>>
>>>> If I simulate memory allocation failure by replacing the first strdup in
>>>> update_master_pl_info() with 'fn1 = NULL;' (instead of 'fn1 =
>>>> av_strdup(s->url);'), then the index.m3u8 file is not created in the
>>>> test subfolder, but in the current directory.
>>> Yes, you are right, I have not reproduced by this way, I double checked this way, it really have the problem,
>>>
>>>> (If you believed that av_strdup() failures don't affect the outcome,
>>>> then you could have replaced all 'temp = av_strdup(str); dir =
>>>> av_dirname(temp);' with 'dir = ".";'.)
>>>>
>>>> - Andreas
>>>>
>>>> PS: What about the rest of this patchset?
>>> I have no option for other patch, only this one, because i remember Limin Wang submit one patch about this patch and I cannot not reproduced the problem which use the same way above that time, maybe I forget something i not attention. So just asked you at this patch.
>>> I merge that patch because:
>>> 1. I cannot reproduce the bug, so have no reason to object it.
>>> 2. The other part maybe exit if strdup failed. (Real no memory for other part.)
>>
>> And what about the other patches of this patchset? Do you object to me
>> applying them? I'll apply them tomorrow if you don't object.
> of course, you can apply them ;)
Applied. Thanks.

- Andreas