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authorAmir Goldstein <amir73il@gmail.com>2018-09-28 21:00:48 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2018-10-04 14:49:10 +0200
commit601350ff58d5415a001769532f6b8333820e5786 (patch)
tree56ac78548e6345a2f5c3a6d96dd5d9fe304d69ed
parent69383c5913a5d74b4aa7e2b78a5cf14ebfbba538 (diff)
ovl: fix access beyond unterminated strings
KASAN detected slab-out-of-bounds access in printk from overlayfs, because string format used %*s instead of %.*s. > BUG: KASAN: slab-out-of-bounds in string+0x298/0x2d0 lib/vsprintf.c:604 > Read of size 1 at addr ffff8801c36c66ba by task syz-executor2/27811 > > CPU: 0 PID: 27811 Comm: syz-executor2 Not tainted 4.19.0-rc5+ #36 ... > printk+0xa7/0xcf kernel/printk/printk.c:1996 > ovl_lookup_index.cold.15+0xe8/0x1f8 fs/overlayfs/namei.c:689 Reported-by: syzbot+376cea2b0ef340db3dd4@syzkaller.appspotmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin") Cc: <stable@vger.kernel.org> # v4.13
-rw-r--r--fs/overlayfs/namei.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index f28711846dd6..9c0ca6a7becf 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -686,7 +686,7 @@ struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
index = NULL;
goto out;
}
- pr_warn_ratelimited("overlayfs: failed inode index lookup (ino=%lu, key=%*s, err=%i);\n"
+ pr_warn_ratelimited("overlayfs: failed inode index lookup (ino=%lu, key=%.*s, err=%i);\n"
"overlayfs: mount with '-o index=off' to disable inodes index.\n",
d_inode(origin)->i_ino, name.len, name.name,
err);