Patch "pipe: fix off-by-one error when checking buffer limits" has been added to the 4.15-stable tree

[<gregkh@linuxfoundation.org>]

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 4.15-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-fix-off-by-one-error-when-checking-buffer-limits.patch
and it can be found in the queue-4.15 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
@@ -610,12 +610,12 @@ 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-4.15/pipe-fix-off-by-one-error-when-checking-buffer-limits.patch
queue-4.15/crypto-hash-annotate-algorithms-taking-optional-key.patch
queue-4.15/crypto-cryptd-pass-through-absence-of-setkey.patch
queue-4.15/crypto-hash-prevent-using-keyed-hashes-without-setting-key.patch
queue-4.15/ubifs-free-the-encrypted-symlink-target.patch
queue-4.15/pipe-actually-allow-root-to-exceed-the-pipe-buffer-limits.patch
queue-4.15/kernel-relay.c-revert-kernel-relay.c-fix-potential-memory-leak.patch
queue-4.15/nfs-reject-request-for-id_legacy-key-without-auxdata.patch
queue-4.15/crypto-poly1305-remove-setkey-method.patch
queue-4.15/crypto-sha512-mb-initialize-pending-lengths-correctly.patch
queue-4.15/crypto-hash-introduce-crypto_hash_alg_has_setkey.patch
queue-4.15/crypto-mcryptd-pass-through-absence-of-setkey.patch