[Bf-committers] [PATCH] Patch to storage.c to avoid crash on long userids

[Campbell Barton]

applied a fix for this in the render branch, will merge to trunk in a day or 2.
http://markmail.org/message/awnbh2zzdivks657

On Mon, Mar 29, 2010 at 4:11 PM, Jochen Schmitt <Jochen at herr-schmitt.de> wrote:
> Am 29.03.2010 11:43, schrieb Rob M:
>> Hi,
>>
>> The patch is bad style. You should not pass literal sizes to strncpy - what
>> happens when someone changes the size of the array?
>> Passing sizeof(files[num].owner) is better (but doesn't allow easy
>> translation from 8bit chars to wide chars).
>> Would it not also be better to increase the size of the owner field as well
>> as not overflowing the array?
>>
>>
> Thank you for your feedback. You have right that I should use
> sizeof(...) instead
> of a literal constant to get more flexible for the case when the
> definition of
> the owner member may been changed.
>
> For an increasement of the owner field, it may be necessary to know a
> maximum
> length which an userid may have. Unfportunately, I doesn't know any
> limitation for it.
>
> At last as far as I know the getpwent() function only returns 8bit data,
> so a discussion
> of translation to 16bit char is more theoratical, because in this case
> we have to call
> a special function to do this translation.
>
> An inproved version of the patch you may find at the end of this mail.
>
> Best Regards:
>
> Jochen Schmitt
>
> diff -up blender/source/blender/blenlib/intern/storage.c.uid
> blender/source/blender/blenlib/intern/storage.c
> --- blender/source/blender/blenlib/intern/storage.c.uid    2010-03-28
> 19:18:49.511022187 +0200
> +++ blender/source/blender/blenlib/intern/storage.c    2010-03-29
> 15:51:00.164136396 +0200
> @@ -331,7 +331,8 @@ void BLI_adddirstrings()
>             struct passwd *pwuser;
>             pwuser = getpwuid(files[num].s.st_uid);
>             if ( pwuser ) {
> -            strcpy(files[num].owner, pwuser->pw_name);
> +              strncpy(files[num].owner, pwuser->pw_name,
> sizeof(files(num].owner)-1);
> +              files[num].owner[sizeof(files{num].owner)-1] = '\0';
>             } else {
>                 sprintf(files[num].owner, "%d", files[num].s.st_uid);
>             }
>
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-- 
- Campbell