This is a note to let you know that I've just added the patch titled

pipe: fix off-by-one error when checking buffer limits

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: pipe-fix-off-by-one-error-when-checking-buffer-limits.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 9903a91c763ecdae333a04a9d89d79d2b8966503 Mon Sep 17 00:00:00 2001

From: Eric Biggers ebiggers@google.com Date: Tue, 6 Feb 2018 15:41:56 -0800 Subject: pipe: fix off-by-one error when checking buffer limits

From: Eric Biggers ebiggers@google.com

commit 9903a91c763ecdae333a04a9d89d79d2b8966503 upstream.

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@gmail.com Fixes: b0b91d18e2e9 ("pipe: fix limit checking in pipe_set_size()") Signed-off-by: Eric Biggers ebiggers@google.com Acked-by: Willy Tarreau w@1wt.eu 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 Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- fs/pipe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/pipe.c +++ b/fs/pipe.c @@ -609,12 +609,12 @@ 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 stable-queue which might be from ebiggers@google.com are

queue-4.9/pipe-fix-off-by-one-error-when-checking-buffer-limits.patch queue-4.9/crypto-cryptd-pass-through-absence-of-setkey.patch queue-4.9/pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits.patch queue-4.9/kernel-relay.c-revert-kernel-relay.c-fix-potential-memory-leak.patch queue-4.9/nfs-reject-request-for-id_legacy-key-without-auxdata.patch queue-4.9/crypto-poly1305-remove-setkey-method.patch queue-4.9/crypto-sha512-mb-initialize-pending-lengths-correctly.patch queue-4.9/crypto-hash-introduce-crypto_hash_alg_has_setkey.patch queue-4.9/crypto-mcryptd-pass-through-absence-of-setkey.patch