From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9BD0439FC6; Fri, 24 Nov 2023 18:10:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="sbdgbp+u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2BEEEC433C7; Fri, 24 Nov 2023 18:10:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1700849446; bh=2RJUMDGp/35m/6HICiS7PxAqvDjqFNffyeGzCGn6xao=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sbdgbp+u2s5wbTQUdXeFcO4EP2yg4u9/ITKOmsaiRaSf1hlR/ZvwkcNBvFIOEbLBq WjWCt0IfwYSNyEe8srnWmjuW52QduYL6KIDkPC8kk7RR/BzwyrYjqmDXI6wMTMcywf kTgyGpEN4WcepVjTccUO8bbUs1xzZI6LtFdX8jbA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shigeru Yoshida , Simon Horman , "David S. Miller" , Sasha Levin Subject: [PATCH 6.6 184/530] tty: Fix uninit-value access in ppp_sync_receive() Date: Fri, 24 Nov 2023 17:45:50 +0000 Message-ID: <20231124172033.679243724@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231124172028.107505484@linuxfoundation.org> References: <20231124172028.107505484@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shigeru Yoshida [ Upstream commit 719639853d88071dfdfd8d9971eca9c283ff314c ] KMSAN reported the following uninit-value access issue: ===================================================== BUG: KMSAN: uninit-value in ppp_sync_input drivers/net/ppp/ppp_synctty.c:690 [inline] BUG: KMSAN: uninit-value in ppp_sync_receive+0xdc9/0xe70 drivers/net/ppp/ppp_synctty.c:334 ppp_sync_input drivers/net/ppp/ppp_synctty.c:690 [inline] ppp_sync_receive+0xdc9/0xe70 drivers/net/ppp/ppp_synctty.c:334 tiocsti+0x328/0x450 drivers/tty/tty_io.c:2295 tty_ioctl+0x808/0x1920 drivers/tty/tty_io.c:2694 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0x211/0x400 fs/ioctl.c:857 __x64_sys_ioctl+0x97/0xe0 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b Uninit was created at: __alloc_pages+0x75d/0xe80 mm/page_alloc.c:4591 __alloc_pages_node include/linux/gfp.h:238 [inline] alloc_pages_node include/linux/gfp.h:261 [inline] __page_frag_cache_refill+0x9a/0x2c0 mm/page_alloc.c:4691 page_frag_alloc_align+0x91/0x5d0 mm/page_alloc.c:4722 page_frag_alloc include/linux/gfp.h:322 [inline] __netdev_alloc_skb+0x215/0x6d0 net/core/skbuff.c:728 netdev_alloc_skb include/linux/skbuff.h:3225 [inline] dev_alloc_skb include/linux/skbuff.h:3238 [inline] ppp_sync_input drivers/net/ppp/ppp_synctty.c:669 [inline] ppp_sync_receive+0x237/0xe70 drivers/net/ppp/ppp_synctty.c:334 tiocsti+0x328/0x450 drivers/tty/tty_io.c:2295 tty_ioctl+0x808/0x1920 drivers/tty/tty_io.c:2694 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0x211/0x400 fs/ioctl.c:857 __x64_sys_ioctl+0x97/0xe0 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b CPU: 0 PID: 12950 Comm: syz-executor.1 Not tainted 6.6.0-14500-g1c41041124bd #10 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014 ===================================================== ppp_sync_input() checks the first 2 bytes of the data are PPP_ALLSTATIONS and PPP_UI. However, if the data length is 1 and the first byte is PPP_ALLSTATIONS, an access to an uninitialized value occurs when checking PPP_UI. This patch resolves this issue by checking the data length. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Shigeru Yoshida Reviewed-by: Simon Horman Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ppp/ppp_synctty.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ppp/ppp_synctty.c b/drivers/net/ppp/ppp_synctty.c index ebcdffdf4f0e0..ea261a628786b 100644 --- a/drivers/net/ppp/ppp_synctty.c +++ b/drivers/net/ppp/ppp_synctty.c @@ -687,7 +687,7 @@ ppp_sync_input(struct syncppp *ap, const u8 *buf, const u8 *flags, int count) /* strip address/control field if present */ p = skb->data; - if (p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) { + if (skb->len >= 2 && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) { /* chop off address/control */ if (skb->len < 3) goto err; -- 2.42.0