The function ext2_xattr_set calls brelse(bh) to drop the reference count of bh. After that, bh may be freed. However, following brelse(bh), it reads bh->b_data via macro HDR(bh). This may result in a use-after-free bug. This patch moves brelse(bh) after reading field. Signed-off-by: Pan Bian <bianpan2016@xxxxxxx> --- fs/ext2/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c index 62d9a659a..dd8f10d 100644 --- a/fs/ext2/xattr.c +++ b/fs/ext2/xattr.c @@ -612,9 +612,9 @@ bad_block: ext2_error(sb, "ext2_xattr_set", } cleanup: - brelse(bh); if (!(bh && header == HDR(bh))) kfree(header); + brelse(bh); up_write(&EXT2_I(inode)->xattr_sem); return error; -- 2.7.4
