Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1551228

[PATCH 4.9 34/83] vfs,mm: fix return value of read() at s_maxbytes

Show all headers | View raw

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Linus Torvalds <torvalds@linux-foundation.org>

commit d05c5f7ba164aed3db02fb188c26d0dd94f5455b upstream.

We truncated the possible read iterator to s_maxbytes in commit
c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()"),
but our end condition handling was wrong: it's not an error to try to
read at the end of the file.

Reading past the end should return EOF (0), not EINVAL.

See for example

  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1649342
  http://lists.gnu.org/archive/html/bug-coreutils/2016-12/msg00008.html

where a md5sum of a maximally sized file fails because the final read is
exactly at s_maxbytes.

Fixes: c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
Reported-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Cc: Wei Fang <fangwei1@huawei.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 mm/filemap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1686,7 +1686,7 @@ static ssize_t do_generic_file_read(stru
 	int error = 0;
 
 	if (unlikely(*ppos >= inode->i_sb->s_maxbytes))
-		return -EINVAL;
+		return 0;
 	iov_iter_truncate(iter, inode->i_sb->s_maxbytes);
 
 	index = *ppos >> PAGE_SHIFT;

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 4.9 00/83] 4.9.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:20 +0100
  [PATCH 4.9 68/83] CIFS: Fix a possible memory corruption during reconnect Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 26/83] ALSA: hda - Gate the mic jack on HP Z1 Gen3 AiO Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 33/83] mm: Add a user_ns owner to mm_struct and fix ptrace permission checks Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 38/83] ext4: dont lock buffer in ext4_commit_super if holding spinlock Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 39/83] ext4: fix mballoc breakage with 64k block size Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 17/83] usb: gadget: f_uac2: fix error handling at afunc_bind Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 41/83] ext4: use more strict checks for inodes_per_block on mount Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 36/83] ptrace: Dont allow accessing an undumpable mm Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 56/83] PM / OPP: Pass opp_table to dev_pm_opp_put_regulator() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 35/83] ptrace: Capture the ptracers creds not PT_PTRACE_CAP Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 42/83] ext4: fix in-superblock mount options processing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 40/83] ext4: fix stack memory corruption with 64k block size Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 25/83] ALSA: hda - fix headset-mic problem on a Dell laptop Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 64/83] dm raid: fix discard support regression Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 31/83] splice: reinstate SIGPIPE/EPIPE handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 59/83] dm table: fix all_blk_mq inconsistency when an empty table is loaded Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 34/83] vfs,mm: fix return value of read() at s_maxbytes Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 54/83] mm, page_alloc: keep pcp count and list contents in sync if struct page is corrupted Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 32/83] block_dev: dont test bdev->bd_contains when it is not stable Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 13/83] USB: cdc-acm: add device id for GW Instek AFG-125 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 12/83] USB: serial: kl5kusb105: fix open error path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 30/83] fs: exec: apply CLOEXEC before changing dumpable task flags Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 29/83] exec: Ensure mm->user_ns contains the execed files Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 62/83] dm crypt: mark key as invalid until properly loaded Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 28/83] clk: ti: omap36xx: Work around sprz319 advisory 2.1 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 66/83] ASoC: intel: Fix crash at suspend/resume without card registration Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 43/83] ext4: add sanity checking to count_overhead() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 55/83] usb: gadget: composite: always set ep->mult to a sensible value Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  [PATCH 4.9 58/83] blk-mq: Do not invoke .queue_rq() for a stopped queue Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-04 21:30 +0100
  Re: [PATCH 4.9 00/83] 4.9.1-stable review Shuah Khan <shuah.kh@samsung.com> - 2017-01-05 01:50 +0100
    Re: [PATCH 4.9 00/83] 4.9.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-05 09:00 +0100
  Re: [PATCH 4.9 00/83] 4.9.1-stable review Guenter Roeck <linux@roeck-us.net> - 2017-01-05 06:00 +0100
    Re: [PATCH 4.9 00/83] 4.9.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-01-05 09:00 +0100

csiph-web