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[v2,4/7] pipe: fix off-by-one error when checking buffer limits

Message ID 20180111052902.14409-5-ebiggers3@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Biggers Jan. 11, 2018, 5:28 a.m. UTC 
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.

Fixes: b0b91d18e2e9 ("pipe: fix limit checking in pipe_set_size()")
Cc: stable@vger.kernel.org
Acked-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/pipe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
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Patch

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)