Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Sun, 03 Feb 2019 14:45:08 +0100 | Subject | [PATCH 3.16 240/305] ext2: fix potential use after free |
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3.16.63-rc1 review patch. If anyone has any objections, please let me know.
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From: Pan Bian <bianpan2016@163.com>
commit ecebf55d27a11538ea84aee0be643dd953f830d5 upstream.
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@163.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- fs/ext2/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/ext2/xattr.c +++ b/fs/ext2/xattr.c @@ -606,9 +606,9 @@ skip_replace: } cleanup: - brelse(bh); if (!(bh && header == HDR(bh))) kfree(header); + brelse(bh); up_write(&EXT2_I(inode)->xattr_sem); return error;
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