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From: Eric Biggers <ebiggers3@gmail.com>
To: linux-fsdevel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	Joe Lawrence <joe.lawrence@redhat.com>,
	Michael Kerrisk <mtk.manpages@gmail.com>,
	Willy Tarreau <w@1wt.eu>, Mikulas Patocka <mpatocka@redhat.com>,
	"Luis R . Rodriguez" <mcgrof@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org, Eric Biggers <ebiggers@google.com>
Subject: [PATCH 4/7] pipe: fix off-by-one error when checking buffer limits
Date: Sun,  7 Jan 2018 21:35:39 -0800	[thread overview]
Message-ID: <20180108053542.6472-5-ebiggers3@gmail.com> (raw)
In-Reply-To: <20180108053542.6472-1-ebiggers3@gmail.com>

From: Eric Biggers <ebiggers@google.com>

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.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/pipe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/pipe.c b/fs/pipe.c
index 847ecc388820..9f20e7128578 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -605,12 +605,12 @@ static unsigned long account_pipe_buffers(struct user_struct *user,
 
 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)
-- 
2.15.1

  parent reply	other threads:[~2018-01-08  5:35 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-08  5:35 [PATCH 0/7] pipe: buffer limits fixes and cleanups Eric Biggers
2018-01-08  5:35 ` [PATCH 1/7] pipe, sysctl: drop 'min' parameter from pipe-max-size converter Eric Biggers
2018-01-09 22:20   ` Kees Cook
2018-01-10  2:29     ` Eric Biggers
2018-01-10 17:30       ` Kees Cook
2018-01-08  5:35 ` [PATCH 2/7] pipe, sysctl: remove pipe_proc_fn() Eric Biggers
2018-01-08  5:35 ` [PATCH 3/7] pipe: actually allow root to exceed the pipe buffer limits Eric Biggers
2018-01-09 22:23   ` Kees Cook
2018-01-10  2:34     ` Eric Biggers
2018-01-08  5:35 ` Eric Biggers [this message]
2018-01-08  6:42   ` [PATCH 4/7] pipe: fix off-by-one error when checking " Willy Tarreau
2018-01-08  5:35 ` [PATCH 5/7] pipe: reject F_SETPIPE_SZ with size over UINT_MAX Eric Biggers
2018-01-09 22:24   ` Kees Cook
2018-01-08  5:35 ` [PATCH 6/7] pipe: simplify round_pipe_size() Eric Biggers
2018-01-09 22:27   ` Kees Cook
2018-01-10  2:52     ` Eric Biggers
2018-01-10  3:13       ` Kees Cook
2018-01-08  5:35 ` [PATCH 7/7] pipe: read buffer limits atomically Eric Biggers
2018-01-09 22:27   ` Kees Cook

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