From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x224sy+Oa2mNdvUl98TNKOeTqHaXyWis4tWHUR80Yt5c9eB4PueJHsy84L8xkZkSENGoES2yT ARC-Seal: i=1; a=rsa-sha256; t=1517256670; cv=none; d=google.com; s=arc-20160816; b=k60o8BkOEm1cmdRZiqtFPcHeDkNWbp/+Wi7Gk5PrD3o4RoSjdBr/a6OKvgA3btFU2U HSyb4+7AojHPK9P4CT8SqnOipSwvKGimEuM+oGlRuxuS472ZlX6tz/Q3OZ1EvvY4CkSW u7bE2sdcWMdeqZ1xmV3i/B2572kBvSidM9w/nYYUqmy7IKEIEpvZdeO2F4e6jZA/6yk5 jRZv7I2Nn0d1hbL5Np2xvmVMQUeLQKJch3byw4JywRmdBoAlwRWukdapDUHtUrVHm9Hb tghseEFBuze20RM0iwuHWPhQhxBC+HYTUnZnwJR2ijR0ro7Wdc77/5zV9BXgWZl9Zhnl Dgpg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=eT7F+Y/Z4yc+z9/X0p5uPNuLIxvl8xNegSB2flJIOHk=; b=C3vylkf7qWMzdzs/t0UuHt0odL7fOD7uBbnYOei3nsurM+VrcB4B1dDABBKwf3NqPs c1chyuoM8C4Rk2DfCZC2jIcjLqOf0gX9lkiKkjD0CtsLSZXvH0c8Hq8zk94gPyv4n+0n hc91E4kCFPR28Xmwam7QUN/+cprxcBPTAmVxcehb8Drz4535s8zFxbpjWx5w20kEoJDT ZnEhECgxKITZfXmpHBdzIX2Qw+yoLyipdidoRgaP8odA9TISMSge3p2iW3XHqhzwvuCu fOX2hYl83LWL+CNugr1vzrKFiIfyuU64JC3J4labYvWDYcTA0zItGhZju5QkjTG5NqA7 fM0g== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "ast@kernel.org, stable@vger.kernel.org, Eric Dumazet" , syzbot , Alexei Starovoitov , Eric Dumazet Subject: [PATCH 4.14 67/71] bpf: fix divides by zero Date: Mon, 29 Jan 2018 13:57:35 +0100 Message-Id: <20180129123832.081586028@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180129123827.271171825@linuxfoundation.org> References: <20180129123827.271171825@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1590958930789791287?= X-GMAIL-MSGID: =?utf-8?q?1590958930789791287?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ upstream commit c366287ebd698ef5e3de300d90cd62ee9ee7373e ] Divides by zero are not nice, lets avoid them if possible. Also do_div() seems not needed when dealing with 32bit operands, but this seems a minor detail. Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: Alexei Starovoitov Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -949,7 +949,7 @@ select_insn: DST = tmp; CONT; ALU_MOD_X: - if (unlikely(SRC == 0)) + if (unlikely((u32)SRC == 0)) return 0; tmp = (u32) DST; DST = do_div(tmp, (u32) SRC); @@ -968,7 +968,7 @@ select_insn: DST = div64_u64(DST, SRC); CONT; ALU_DIV_X: - if (unlikely(SRC == 0)) + if (unlikely((u32)SRC == 0)) return 0; tmp = (u32) DST; do_div(tmp, (u32) SRC);