[asterisk-dev] [Code Review]: Fix a large variety of errors caused by negative return codes

Matt Jordan reviewboard at asterisk.org
Mon Apr 16 11:10:35 CDT 2012 


> On April 13, 2012, 5:40 p.m., rmudgett wrote:
> > /branches/1.8/main/manager.c, lines 3633-3636
> > <https://reviewboard.asterisk.org/r/1863/diff/4/?file=27300#file27300line3633>
> >
> >     Probably should quit if either buffer fails to allocate.

Agreed.


> On April 13, 2012, 5:40 p.m., rmudgett wrote:
> > /branches/1.8/main/translate.c, lines 1118-1121
> > <https://reviewboard.asterisk.org/r/1863/diff/4/?file=27301#file27301line1118>
> >
> >     This isn't quite true since x will never be zero because it is a 1 bit walking through the integer.  It is then further filtered by the audio format mask.

True.  I was thinking in the context of src_audio/src_video, which isn't the case here.  I'll modify the comments accordingly.


> On April 13, 2012, 5:40 p.m., rmudgett wrote:
> > /branches/1.8/main/translate.c, lines 1151-1154
> > <https://reviewboard.asterisk.org/r/1863/diff/4/?file=27301#file27301line1151>
> >
> >     Same here but is filtered by the video mask.

Changed.


> On April 13, 2012, 5:40 p.m., rmudgett wrote:
> > /branches/1.8/main/manager.c, lines 3630-3631
> > <https://reviewboard.asterisk.org/r/1863/diff/4/?file=27300#file27300line3630>
> >
> >     Clearing the allocated memory via calloc should not be needed here since the buffers are the size of the returned data plus 1.  The buffers are always going to be filled and explicitly terminated.

In the original code, this wasn't the case.  Since we now jump to action_command_cleanup if read fails, we can now  replace these with malloc.


- Matt


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On April 13, 2012, 4:46 p.m., Matt Jordan wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviewboard.asterisk.org/r/1863/
> -----------------------------------------------------------
> 
> (Updated April 13, 2012, 4:46 p.m.)
> 
> 
> Review request for Asterisk Developers.
> 
> 
> Summary
> -------
> 
> Through a static analysis tool, a large number of errors were found that dealt with using potential negative return values in harmful ways.  The following is a summary of the changes for the various affected files:
> 
> * app_voicemail
>   - a negative result from lseek is later passed into mmap as the size of the memory map
>   - a negative result from read closes the various file descriptors and unlinks the output file, but the next check against the return value only checks to see if its non-zero
> * chan_agent - ast_channel_unlock returns a negative value if the item passed to it is NULL or an invalid ao2 object.  strerror cannot accept a negative value.
> * chan_dahdi - if dahdi_get_index returns a negative value, we index directly into an array
> * format_* - various errors not checking return values of ftello and fseek, and passing the results into functions that expect non-negative values
> * func_env - various places where the result of ftello was directly used as input to functions that expect non-negative values
> * asterisk
>   - the request to read returns a negative value.  This causes us to enter into the retry logic.  If we attempt to reconnect and succeed, we would normally proceed in the for(;;) loop and attempt to index into buf using the negative return value from read.  Instead, if we do reconnect, we immediately return to the beginning of the for(;;) loop and attempt a new read.
>   - similar situation - if a read fails, don't attempt to index into a buffer using the return value
> * frame - if we can't determine a preferred codec using the provided values, don't attempt to use an index value that never got set
> * manager 
>   - various failures of mkstemp, lseek were not checked for and could be provided to methods that don't handle negative numbers
>   - passing a negative result from lseek into mmap as the size of the memory map
> * translate - powerof can return a negative result if no bits are set, which would then be used as an index into an array
> * res_agi - if read returns an error, we treated it as if bytes were read from the pipe
> * res_musiconhold - if we fail to spawn spawn_mp3 returns a negative number, we wait a bit and attempt again later.  However, the return 'file descriptor' srcfd is later passed into read.
> * res_rtp_asterisk - ast_rtp_codecs_payload_code can return a negative value if no codecs are found that match between instance1 and the specified payload.  If that's the case, the bridge should be broken, as there are no compatible formats between the two different endpoints (and we shouldn't index into an array using the return value)
> 
> 
> Diffs
> -----
> 
>   /branches/1.8/apps/app_voicemail.c 362134 
>   /branches/1.8/channels/chan_agent.c 362134 
>   /branches/1.8/channels/chan_dahdi.c 362134 
>   /branches/1.8/formats/format_g719.c 362134 
>   /branches/1.8/formats/format_g723.c 362134 
>   /branches/1.8/formats/format_g729.c 362134 
>   /branches/1.8/formats/format_gsm.c 362134 
>   /branches/1.8/formats/format_h263.c 362134 
>   /branches/1.8/formats/format_h264.c 362134 
>   /branches/1.8/formats/format_ilbc.c 362134 
>   /branches/1.8/formats/format_pcm.c 362134 
>   /branches/1.8/formats/format_siren14.c 362134 
>   /branches/1.8/formats/format_siren7.c 362134 
>   /branches/1.8/formats/format_sln.c 362134 
>   /branches/1.8/formats/format_sln16.c 362134 
>   /branches/1.8/formats/format_vox.c 362134 
>   /branches/1.8/formats/format_wav.c 362134 
>   /branches/1.8/formats/format_wav_gsm.c 362134 
>   /branches/1.8/funcs/func_env.c 362134 
>   /branches/1.8/main/asterisk.c 362134 
>   /branches/1.8/main/frame.c 362134 
>   /branches/1.8/main/manager.c 362134 
>   /branches/1.8/main/translate.c 362134 
>   /branches/1.8/res/res_agi.c 362134 
>   /branches/1.8/res/res_musiconhold.c 362134 
>   /branches/1.8/res/res_rtp_asterisk.c 362134 
> 
> Diff: https://reviewboard.asterisk.org/r/1863/diff
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> Matt
> 
>

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