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authorGeert Uytterhoeven <geert@linux-m68k.org>2012-09-29 22:23:19 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-31 09:51:35 -0700
commite17ce2ec38fd766e8f9707701e47f4332d8bb630 (patch)
tree609a59ea45aff2c2a71f4046e5801c84b49ab7f3
parent910e425b29da7b601a99f49e81da666ab8ed5920 (diff)
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sysfs: sysfs_pathname/sysfs_add_one: Use strlcat() instead of strcat()
commit 66081a72517a131430dcf986775f3268aafcb546 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/sysfs/dir.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index ea9120a..567b3db 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -404,20 +404,18 @@ 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;
}
@@ -450,9 +448,11 @@ 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);
}