From: Jan Kara <jack@suse.cz> stable inclusion from stable-v4.19.276 commit 5d029799d381a9ee06209a222cae75f04c5d5304 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ID0RFS CVE: CVE-2023-53506 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 53cafe1d6d8ef9f93318e5bfccc0d24f27d41ced upstream. When merging very long extents we try to push as much length as possible to the first extent. However this is unnecessarily complicated and not really worth the trouble. Furthermore there was a bug in the logic resulting in corrupting extents in the file as syzbot reproducer shows. So just don't bother with the merging of extents that are too long together. CC: stable@vger.kernel.org Reported-by: syzbot+60f291a24acecb3c2bd5@syzkaller.appspotmail.com Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Xinyu Zheng <zhengxinyu6@huawei.com> --- fs/udf/inode.c | 19 ++----------------- 1 file changed, 2 insertions(+), 17 deletions(-) diff --git a/fs/udf/inode.c b/fs/udf/inode.c index b34c9cb208cc..11f104931254 100644 --- a/fs/udf/inode.c +++ b/fs/udf/inode.c @@ -1084,23 +1084,8 @@ static void udf_merge_extents(struct inode *inode, struct kernel_long_ad *laarr, blocksize - 1) >> blocksize_bits)))) { if (((li->extLength & UDF_EXTENT_LENGTH_MASK) + - (lip1->extLength & UDF_EXTENT_LENGTH_MASK) + - blocksize - 1) & ~UDF_EXTENT_LENGTH_MASK) { - lip1->extLength = (lip1->extLength - - (li->extLength & - UDF_EXTENT_LENGTH_MASK) + - UDF_EXTENT_LENGTH_MASK) & - ~(blocksize - 1); - li->extLength = (li->extLength & - UDF_EXTENT_FLAG_MASK) + - (UDF_EXTENT_LENGTH_MASK + 1) - - blocksize; - lip1->extLocation.logicalBlockNum = - li->extLocation.logicalBlockNum + - ((li->extLength & - UDF_EXTENT_LENGTH_MASK) >> - blocksize_bits); - } else { + (lip1->extLength & UDF_EXTENT_LENGTH_MASK) + + blocksize - 1) <= UDF_EXTENT_LENGTH_MASK) { li->extLength = lip1->extLength + (((li->extLength & UDF_EXTENT_LENGTH_MASK) + -- 2.34.1