lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 1 Nov 2017 22:17:41 +0100 From: Willy Tarreau <w@....eu> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org, linux@...ck-us.net Cc: Jan Kara <jack@...e.cz>, "Theodore Ts'o" <tytso@....edu>, stable@...r.kernel.org#3.8+, Willy Tarreau <w@....eu> Subject: [PATCH 3.10 041/139] ext4: fix SEEK_HOLE/SEEK_DATA for blocksize < pagesize From: Jan Kara <jack@...e.cz> commit fcf5ea10992fbac3c7473a1db33d56a139333cd1 upstream. ext4_find_unwritten_pgoff() does not properly handle a situation when starting index is in the middle of a page and blocksize < pagesize. The following command shows the bug on filesystem with 1k blocksize: xfs_io -f -c "falloc 0 4k" \ -c "pwrite 1k 1k" \ -c "pwrite 3k 1k" \ -c "seek -a -r 0" foo In this example, neither lseek(fd, 1024, SEEK_HOLE) nor lseek(fd, 2048, SEEK_DATA) will return the correct result. Fix the problem by neglecting buffers in a page before starting offset. Reported-by: Andreas Gruenbacher <agruenba@...hat.com> Signed-off-by: Theodore Ts'o <tytso@....edu> Signed-off-by: Jan Kara <jack@...e.cz> CC: stable@...r.kernel.org # 3.8+ Signed-off-by: Willy Tarreau <w@....eu> --- fs/ext4/file.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index ec9770f..d490d6e 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -382,6 +382,8 @@ static int ext4_find_unwritten_pgoff(struct inode *inode, lastoff = page_offset(page); bh = head = page_buffers(page); do { + if (lastoff + bh->b_size <= startoff) + goto next; if (buffer_uptodate(bh) || buffer_unwritten(bh)) { if (whence == SEEK_DATA) @@ -396,6 +398,7 @@ static int ext4_find_unwritten_pgoff(struct inode *inode, unlock_page(page); goto out; } +next: lastoff += bh->b_size; bh = bh->b_this_page; } while (bh != head); -- 2.8.0.rc2.1.gbe9624a
Powered by blists - more mailing lists