* [merged] pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits.patch removed from -mm tree
@ 2018-02-07 20:00 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2018-02-07 20:00 UTC (permalink / raw)
To: ebiggers, joe.lawrence, keescook, mcgrof, mm-commits, mpatocka,
mtk.manpages, stable, viro, w
The patch titled
Subject: pipe: actually allow root to exceed the pipe buffer limits
has been removed from the -mm tree. Its filename was
pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Eric Biggers <ebiggers@google.com>
Subject: pipe: actually allow root to exceed the pipe buffer limits
pipe-user-pages-hard and pipe-user-pages-soft are only supposed to apply
to unprivileged users, as documented in both Documentation/sysctl/fs.txt
and the pipe(7) man page.
However, the capabilities are actually only checked when increasing a
pipe's size using F_SETPIPE_SZ, not when creating a new pipe. Therefore,
if pipe-user-pages-hard has been set, the root user can run into it and be
unable to create pipes. Similarly, if pipe-user-pages-soft has been set,
the root user can run into it and have their pipes limited to 1 page each.
Fix this by allowing the privileged override in both cases.
Link: http://lkml.kernel.org/r/20180111052902.14409-4-ebiggers3@gmail.com
Fixes: 759c01142a5d ("pipe: limit the per-user amount of pages allocated in pipes")
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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
fs/pipe.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff -puN fs/pipe.c~pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits fs/pipe.c
--- a/fs/pipe.c~pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits
+++ a/fs/pipe.c
@@ -613,6 +613,11 @@ static bool too_many_pipe_buffers_hard(u
return pipe_user_pages_hard && user_bufs >= pipe_user_pages_hard;
}
+static bool is_unprivileged_user(void)
+{
+ return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
+}
+
struct pipe_inode_info *alloc_pipe_info(void)
{
struct pipe_inode_info *pipe;
@@ -629,12 +634,12 @@ struct pipe_inode_info *alloc_pipe_info(
user_bufs = account_pipe_buffers(user, 0, pipe_bufs);
- if (too_many_pipe_buffers_soft(user_bufs)) {
+ if (too_many_pipe_buffers_soft(user_bufs) && is_unprivileged_user()) {
user_bufs = account_pipe_buffers(user, pipe_bufs, 1);
pipe_bufs = 1;
}
- if (too_many_pipe_buffers_hard(user_bufs))
+ if (too_many_pipe_buffers_hard(user_bufs) && is_unprivileged_user())
goto out_revert_acct;
pipe->bufs = kcalloc(pipe_bufs, sizeof(struct pipe_buffer),
@@ -1065,7 +1070,7 @@ static long pipe_set_size(struct pipe_in
if (nr_pages > pipe->buffers &&
(too_many_pipe_buffers_hard(user_bufs) ||
too_many_pipe_buffers_soft(user_bufs)) &&
- !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) {
+ is_unprivileged_user()) {
ret = -EPERM;
goto out_revert_acct;
}
_
Patches currently in -mm which might be from ebiggers@google.com are
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2018-02-07 20:00 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-02-07 20:00 [merged] pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits.patch removed from -mm tree akpm
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).