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authorEric Biggers <ebiggers@google.com>2018-02-07 02:41:45 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-07 05:32:47 +0300
commit4c2e4befb3cc9ce42d506aa537c9ab504723e98c (patch)
tree5419e5965a7f07a39d1db8767148d547907f9c0d /fs
parente7c52b84fb18f08ce49b6067ae6285aca79084a8 (diff)
downloadlinux-4c2e4befb3cc9ce42d506aa537c9ab504723e98c.tar.xz
pipe, sysctl: drop 'min' parameter from pipe-max-size converter
Patch series "pipe: buffer limits fixes and cleanups", v2. This series simplifies the sysctl handler for pipe-max-size and fixes another set of bugs related to the pipe buffer limits: - The root user wasn't allowed to exceed the limits when creating new pipes. - There was an off-by-one error when checking the limits, so a limit of N was actually treated as N - 1. - F_SETPIPE_SZ accepted values over UINT_MAX. - Reading the pipe buffer limits could be racy. This patch (of 7): Before validating the given value against pipe_min_size, do_proc_dopipe_max_size_conv() calls round_pipe_size(), which rounds the value up to pipe_min_size. Therefore, the second check against pipe_min_size is redundant. Remove it. Link: http://lkml.kernel.org/r/20180111052902.14409-2-ebiggers3@gmail.com Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "Luis R . Rodriguez" <mcgrof@kernel.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/pipe.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index a449ca0ec0c6..1f6ec1051e59 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -35,11 +35,6 @@
*/
unsigned int pipe_max_size = 1048576;
-/*
- * Minimum pipe size, as required by POSIX
- */
-unsigned int pipe_min_size = PAGE_SIZE;
-
/* Maximum allocatable pages per user. Hard limit is unset by default, soft
* matches default values.
*/
@@ -1024,8 +1019,9 @@ unsigned int round_pipe_size(unsigned int size)
{
unsigned long nr_pages;
- if (size < pipe_min_size)
- size = pipe_min_size;
+ /* Minimum pipe size, as required by POSIX */
+ if (size < PAGE_SIZE)
+ size = PAGE_SIZE;
nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
if (nr_pages == 0)