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

[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 ;)
> 
> - Andreas
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Thanks

Steven Liu