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sysfs: sysfs_pathname/sysfs_add_one: Use strlcat() instead of strcat()

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The warning check for duplicate sysfs entries can cause a buffer overflow
when printing the warning, as strcat() doesn't check buffer sizes.
Use strlcat() instead.

Since strlcat() doesn't return a pointer to the passed buffer, unlike
strcat(), I had to convert the nested concatenation in sysfs_add_one() to
an admittedly more obscure comma operator construct, to avoid emitting code
for the concatenation if CONFIG_BUG is disabled.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Geert Uytterhoeven 2012-09-29 22:23:19 +02:00 committed by Greg Kroah-Hartman
parent c0d2af6378
commit 66081a7251
1 changed files with 8 additions and 8 deletions
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16
fs/sysfs/dir.c
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@ -485,20 +485,18 @@ int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
/**
* sysfs_pathname - return full path to sysfs dirent
* @sd: sysfs_dirent whose path we want
* @path: caller allocated buffer
* @path: caller allocated buffer of size PATH_MAX
*
* Gives the name "/" to the sysfs_root entry; any path returned
* is relative to wherever sysfs is mounted.
*
* XXX: does no error checking on @path size
*/
static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)
{
if (sd->s_parent) {
sysfs_pathname(sd->s_parent, path);
strcat(path, "/");
strlcat(path, "/", PATH_MAX);
}
strcat(path, sd->s_name);
strlcat(path, sd->s_name, PATH_MAX);
return path;
}
@ -531,9 +529,11 @@ int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
char *path = kzalloc(PATH_MAX, GFP_KERNEL);
WARN(1, KERN_WARNING
"sysfs: cannot create duplicate filename '%s'\n",
(path == NULL) ? sd->s_name :
strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),
sd->s_name));
(path == NULL) ? sd->s_name
: (sysfs_pathname(acxt->parent_sd, path),
strlcat(path, "/", PATH_MAX),
strlcat(path, sd->s_name, PATH_MAX),
path));
kfree(path);
}