4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Biggers <ebigg...@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-ebigge...@gmail.com Fixes: b0b91d18e2e9 ("pipe: fix limit checking in pipe_set_size()") Signed-off-by: Eric Biggers <ebigg...@google.com> Acked-by: Willy Tarreau <w...@1wt.eu> Acked-by: Kees Cook <keesc...@chromium.org> Acked-by: Joe Lawrence <joe.lawre...@redhat.com> Cc: Alexander Viro <v...@zeniv.linux.org.uk> Cc: "Luis R . Rodriguez" <mcg...@kernel.org> Cc: Michael Kerrisk <mtk.manpa...@gmail.com> Cc: Mikulas Patocka <mpato...@redhat.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gre...@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)
