The patch titled
Subject: pipe: fix off-by-one error when checking buffer limits
has been added to the -mm tree. Its filename is
pipe-fix-off-by-one-error-when-checking-buffer-limits.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/pipe-fix-off-by-one-error-when-checking-buffer-limits.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/pipe-fix-off-by-one-error-when-checking-buffer-limits.patch
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@xxxxxxxxxx>
Subject: pipe: fix off-by-one error when checking buffer limits
With pipe-user-pages-hard set to 'N', users were actually only allowed up
to 'N - 1' buffers; and likewise for pipe-user-pages-soft.
Fix this to allow up to 'N' buffers, as would be expected.
Link: http://lkml.kernel.org/r/20180111052902.14409-5-ebiggers3@xxxxxxxxx
Fixes: b0b91d18e2e9 ("pipe: fix limit checking in pipe_set_size()")
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Acked-by: Willy Tarreau <w@xxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: "Luis R . Rodriguez" <mcgrof@xxxxxxxxxx>
Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx>
Cc: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/pipe.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN fs/pipe.c~pipe-fix-off-by-one-error-when-checking-buffer-limits fs/pipe.c
--- a/fs/pipe.c~pipe-fix-off-by-one-error-when-checking-buffer-limits
+++ a/fs/pipe.c
@@ -605,12 +605,12 @@ static unsigned long account_pipe_buffer
static bool too_many_pipe_buffers_soft(unsigned long user_bufs)
{
- return pipe_user_pages_soft && user_bufs >= pipe_user_pages_soft;
+ return pipe_user_pages_soft && user_bufs > pipe_user_pages_soft;
}
static bool too_many_pipe_buffers_hard(unsigned long user_bufs)
{
- return pipe_user_pages_hard && user_bufs >= pipe_user_pages_hard;
+ return pipe_user_pages_hard && user_bufs > pipe_user_pages_hard;
}
static bool is_unprivileged_user(void)
_
Patches currently in -mm which might be from ebiggers@xxxxxxxxxx are
userfaultfd-convert-to-use-anon_inode_getfd.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