From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:38064 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755052AbeBOIdc (ORCPT ); Thu, 15 Feb 2018 03:33:32 -0500 Subject: Patch "pipe: actually allow root to exceed the pipe buffer limits" has been added to the 4.14-stable tree To: ebiggers@google.com, akpm@linux-foundation.org, gregkh@linuxfoundation.org, joe.lawrence@redhat.com, keescook@chromium.org, mcgrof@kernel.org, mpatocka@redhat.com, mtk.manpages@gmail.com, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, w@1wt.eu Cc: , From: Date: Thu, 15 Feb 2018 09:32:50 +0100 Message-ID: <151868357015392@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled pipe: actually allow root to exceed the pipe buffer limits to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 85c2dd5473b2718b4b63e74bfeb1ca876868e11f Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 6 Feb 2018 15:41:53 -0800 Subject: pipe: actually allow root to exceed the pipe buffer limits From: Eric Biggers commit 85c2dd5473b2718b4b63e74bfeb1ca876868e11f upstream. 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 Acked-by: Kees Cook Acked-by: Joe Lawrence Cc: Alexander Viro Cc: "Luis R . Rodriguez" Cc: Michael Kerrisk Cc: Mikulas Patocka Cc: Willy Tarreau Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/pipe.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/fs/pipe.c +++ b/fs/pipe.c @@ -618,6 +618,11 @@ 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; @@ -634,12 +639,12 @@ 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), @@ -1069,7 +1074,7 @@ 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 stable-queue which might be from ebiggers@google.com are queue-4.14/pipe-fix-off-by-one-error-when-checking-buffer-limits.patch queue-4.14/crypto-hash-annotate-algorithms-taking-optional-key.patch queue-4.14/crypto-cryptd-pass-through-absence-of-setkey.patch queue-4.14/crypto-hash-prevent-using-keyed-hashes-without-setting-key.patch queue-4.14/ubifs-free-the-encrypted-symlink-target.patch queue-4.14/pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits.patch queue-4.14/kernel-relay.c-revert-kernel-relay.c-fix-potential-memory-leak.patch queue-4.14/nfs-reject-request-for-id_legacy-key-without-auxdata.patch queue-4.14/crypto-poly1305-remove-setkey-method.patch queue-4.14/crypto-sha512-mb-initialize-pending-lengths-correctly.patch queue-4.14/crypto-hash-introduce-crypto_hash_alg_has_setkey.patch queue-4.14/crypto-mcryptd-pass-through-absence-of-setkey.patch