bcache: Strip endline when writing the label through sysfs

sysfs attributes with unusual characters have crappy failure modes
in Squeeze (udev 164); later versions of udev are unaffected.

This should make these characters more unusual.

Signed-off-by: Gabriel de Perthuis <g2p.code@gmail.com>
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: linux-stable <stable@vger.kernel.org> # >= v3.10

diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 12a2c2846f994a1e2d51bf79374426df96893418..a87fbb5a093f250cb8f6a30d32efbfdaa16f9b3f 100644 (file)
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -223,8 +223,13 @@ STORE(__cached_dev)
        }
 
        if (attr == &sysfs_label) {
-               /* note: endlines are preserved */
-               memcpy(dc->sb.label, buf, SB_LABEL_SIZE);
+               if (size > SB_LABEL_SIZE)
+                       return -EINVAL;
+               memcpy(dc->sb.label, buf, size);
+               if (size < SB_LABEL_SIZE)
+                       dc->sb.label[size] = '\0';
+               if (size && dc->sb.label[size - 1] == '\n')
+                       dc->sb.label[size - 1] = '\0';
                bch_write_bdev_super(dc, NULL);
                if (dc->disk.c) {
                        memcpy(dc->disk.c->uuids[dc->disk.id].label,