--- /dev/null
+From 66081a72517a131430dcf986775f3268aafcb546 Mon Sep 17 00:00:00 2001
+From: Geert Uytterhoeven <geert@linux-m68k.org>
+Date: Sat, 29 Sep 2012 22:23:19 +0200
+Subject: sysfs: sysfs_pathname/sysfs_add_one: Use strlcat() instead of strcat()
+
+From: Geert Uytterhoeven <geert@linux-m68k.org>
+
+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>
+
+---
+ fs/sysfs/dir.c | 16 ++++++++--------
+ 1 file changed, 8 insertions(+), 8 deletions(-)
+
+--- a/fs/sysfs/dir.c
++++ b/fs/sysfs/dir.c
+@@ -404,20 +404,18 @@ int __sysfs_add_one(struct sysfs_addrm_c
+ /**
+ * 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
+ 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);
+ }
+