From: Hans Verkuil <hans.verkuil(a)cisco.com>
The result of the VIDIOC_PREPARE_BUF ioctl was never copied back
to userspace since it was missing in the switch.
Signed-off-by: Hans Verkuil <hans.verkuil(a)cisco.com>
Acked-by: Sakari Ailus <sakari.ailus(a)linux.intel.com>
Cc: <stable(a)vger.kernel.org> # for v4.15 and up
---
drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index e48d59046086..76ed43e774dd 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -1052,6 +1052,7 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
err = put_v4l2_create32(&karg.v2crt, up);
break;
+ case VIDIOC_PREPARE_BUF:
case VIDIOC_QUERYBUF:
case VIDIOC_QBUF:
case VIDIOC_DQBUF:
--
2.15.1
strscpy() performs the word-at-a-time optimistic reads. So it may
may access the memory past the end of the object, which is perfectly fine
since strscpy() doesn't use that (past-the-end) data and makes sure the
optimistic read won't cross a page boundary.
But KASAN doesn't know anything about that so it will complain.
There are several possible ways to address this issue, but none
are perfect. See https://lkml.kernel.org/r/9f0a9cf6-51f7-cd1f-5dc6-6d510a7b8ec4@virtuozzo.com
It seems the best solution is to simply disable word-at-a-time
optimization. My trivial testing shows that byte-at-a-time
could be up to x4.3 times slower than word-at-a-time.
It may seems like a lot, but it's actually ~1.2e-10 sec per symbol vs
~4.8e-10 sec per symbol on modern hardware. And we don't use strscpy()
in a performance critical paths to copy large amounts of data,
so it shouldn't matter anyway.
Fixes: 30035e45753b7 ("string: provide strscpy()")
Signed-off-by: Andrey Ryabinin <aryabinin(a)virtuozzo.com>
Cc: <stable(a)vger.kernel.org>
---
lib/string.c | 38 --------------------------------------
1 file changed, 38 deletions(-)
diff --git a/lib/string.c b/lib/string.c
index 64a9e33f1daa..6205dd71aa0f 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -29,7 +29,6 @@
#include <linux/errno.h>
#include <asm/byteorder.h>
-#include <asm/word-at-a-time.h>
#include <asm/page.h>
#ifndef __HAVE_ARCH_STRNCASECMP
@@ -177,45 +176,8 @@ EXPORT_SYMBOL(strlcpy);
*/
ssize_t strscpy(char *dest, const char *src, size_t count)
{
- const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
- size_t max = count;
long res = 0;
- if (count == 0)
- return -E2BIG;
-
-#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
- /*
- * If src is unaligned, don't cross a page boundary,
- * since we don't know if the next page is mapped.
- */
- if ((long)src & (sizeof(long) - 1)) {
- size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1));
- if (limit < max)
- max = limit;
- }
-#else
- /* If src or dest is unaligned, don't do word-at-a-time. */
- if (((long) dest | (long) src) & (sizeof(long) - 1))
- max = 0;
-#endif
-
- while (max >= sizeof(unsigned long)) {
- unsigned long c, data;
-
- c = *(unsigned long *)(src+res);
- if (has_zero(c, &data, &constants)) {
- data = prep_zero_mask(c, data, &constants);
- data = create_zero_mask(data);
- *(unsigned long *)(dest+res) = c & zero_bytemask(data);
- return res + find_zero(data);
- }
- *(unsigned long *)(dest+res) = c;
- res += sizeof(unsigned long);
- count -= sizeof(unsigned long);
- max -= sizeof(unsigned long);
- }
-
while (count) {
char c;
--
2.13.6
On Tue, Jan 30, 2018 at 05:09:07AM +0000, Harsh Shandilya wrote:
> On Tue 30 Jan, 2018, 2:20 AM Greg Kroah-Hartman, <gregkh(a)linuxfoundation.org>
> wrote:
>
> > This is the start of the stable review cycle for the 3.18.93 release.
> > There are 52 patches in this series, all will be posted as a response
> > to this one. If anyone has any issues with these being applied, please
> > let me know.
> >
> > Responses should be made by Wed Jan 31 12:36:07 UTC 2018.
> > Anything received after that time might be too late.
> >
> > The whole patch series can be found in one patch at:
> >
> > kernel.org/pub/linux/kernel/v3.x/stable-review/patch-3.18.93-rc1.gz
> > or in the git tree and branch at:
> > git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
> > linux-3.18.y
> > and the diffstat can be found below.
> >
> > thanks,
> >
> > greg k-h
> >
>
> Builds and boots on the OnePlus 3, no dmesg or userspace regressions.
Yeah, it's still working! :)
thanks for testing and letting me know.
greg k-h
The patch titled
Subject: kernel/relay.c: revert "kernel/relay.c: fix potential memory leak"
has been added to the -mm tree. Its filename is
revert-kernel-relayc-fix-potential-memory-leak.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/revert-kernel-relayc-fix-potential…
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/revert-kernel-relayc-fix-potential…
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Eric Biggers <ebiggers(a)google.com>
Subject: kernel/relay.c: revert "kernel/relay.c: fix potential memory leak"
This reverts ba62bafe942b159a6 ("kernel/relay.c: fix potential memory leak").
This commit introduced a double free bug, because 'chan' is already
freed by the line:
kref_put(&chan->kref, relay_destroy_channel);
This bug was found by syzkaller, using the BLKTRACESETUP ioctl.
Link: http://lkml.kernel.org/r/20180127004759.101823-1-ebiggers3@gmail.com
Fixes: ba62bafe942b ("kernel/relay.c: fix potential memory leak")
Signed-off-by: Eric Biggers <ebiggers(a)google.com>
Reported-by: syzbot <syzkaller(a)googlegroups.com>
Reviewed-by: Andrew Morton <akpm(a)linux-foundation.org>
Cc: Zhouyi Zhou <yizhouzhou(a)ict.ac.cn>
Cc: Jens Axboe <axboe(a)kernel.dk>
Cc: <stable(a)vger.kernel.org> [4.7+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
kernel/relay.c | 1 -
1 file changed, 1 deletion(-)
diff -puN kernel/relay.c~revert-kernel-relayc-fix-potential-memory-leak kernel/relay.c
--- a/kernel/relay.c~revert-kernel-relayc-fix-potential-memory-leak
+++ a/kernel/relay.c
@@ -611,7 +611,6 @@ free_bufs:
kref_put(&chan->kref, relay_destroy_channel);
mutex_unlock(&relay_channels_mutex);
- kfree(chan);
return NULL;
}
EXPORT_SYMBOL_GPL(relay_open);
_
Patches currently in -mm which might be from ebiggers(a)google.com are
userfaultfd-convert-to-use-anon_inode_getfd.patch
revert-kernel-relayc-fix-potential-memory-leak.patch
pipe-sysctl-drop-min-parameter-from-pipe-max-size-converter.patch
pipe-sysctl-remove-pipe_proc_fn.patch
pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits.patch
pipe-fix-off-by-one-error-when-checking-buffer-limits.patch
pipe-reject-f_setpipe_sz-with-size-over-uint_max.patch
pipe-simplify-round_pipe_size.patch
pipe-read-buffer-limits-atomically.patch