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authorEric Biggers <ebiggers@google.com>2018-02-06 15:41:56 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-06 18:32:47 -0800
commit9903a91c763ecdae333a04a9d89d79d2b8966503 (patch)
tree62181e45190b53365475094bc2dd66ec9ad415b4 /fs
parent85c2dd5473b2718b4b63e74bfeb1ca876868e11f (diff)
downloadlinux-9903a91c763ecdae333a04a9d89d79d2b8966503.tar.gz
pipe: fix off-by-one error when checking buffer limits
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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/pipe.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index 04acfad4692b..46c30ac777da 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)