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
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 4fe6ab2fbe2e..924dcfdae111 100644
--- 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,