lkml.org 
[lkml]   [2013]   [Nov]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH] double free in decompressor.c
On 22/11/13 21:50, Geyslan Gregório Bem wrote:
> Coverity caught double free possibility (CID 1130962).
>
> I can patch this, but I have to know if is correct to free comp_opts
> in the function squashfs_decompressor_create() or it had to be done in
> the caller. My bet is the caller.
>
>
> 128void *squashfs_decompressor_setup(struct super_block *sb, unsigned
> short flags)
> 129{
> 130 struct squashfs_sb_info *msblk = sb->s_fs_info;
> 131 void *stream, *comp_opts = get_comp_opts(sb, flags);
> 132
>
> 1. Condition "IS_ERR(comp_opts)", taking false branch
> 133 if (IS_ERR(comp_opts))
> 134 return comp_opts;
> 135
>
> 2. freed_arg: "squashfs_decompressor_create(struct squashfs_sb_info *,
> void *)" frees "comp_opts".[show details]
> 136 stream = squashfs_decompressor_create(msblk, comp_opts);
>
> 3. Condition "IS_ERR(stream)", taking true branch
> 137 if (IS_ERR(stream))

FALSE positive.

squashfs_decompressor_create() frees comp_opts only on success.

If IS_ERR(stream) is true, then comp_opts has not been freed by
squashfs_decompressor_create().

Phillip


>
> CID 1130962 (#1 of 1): Double free (USE_AFTER_FREE)4. double_free:
> Calling "kfree(void const *)" frees pointer "comp_opts" which has
> already been freed.
> 138 kfree(comp_opts);
> 139
> 140 return stream;
> 141}
>
>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2013-11-23 00:41    [W:0.165 / U:0.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site