From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DE8AC4708A for ; Wed, 23 Nov 2022 09:27:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237526AbiKWJ1x (ORCPT ); Wed, 23 Nov 2022 04:27:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237636AbiKWJ0t (ORCPT ); Wed, 23 Nov 2022 04:26:49 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5671710B427 for ; Wed, 23 Nov 2022 01:25:55 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 01F01B81EE5 for ; Wed, 23 Nov 2022 09:25:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 585CAC433C1; Wed, 23 Nov 2022 09:25:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669195552; bh=D9AwE9MwlcOjNKcKoWPuChCdg7H0zaQ+5h8M/hg2WqY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Sh5hX6fYNyktEgIrCdqOGYqx2ud2Via+OQGjBDobmV4F3+u+Y4QVRC+puIb29eX/K AcIo8rIdprJXD6agjLWhBymQuQoQmMrjWfIkQKktOfkyHxJEJgBQ+QuYza7i/9Czwj 7IXcrgNXQBBDb2iJoF56odGZEOS7ptog//WK+dYM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alban Crequy , Andrii Nakryiko , Francis Laniel , Andrew Morton Subject: [PATCH 5.10 116/149] maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault() Date: Wed, 23 Nov 2022 09:51:39 +0100 Message-Id: <20221123084602.113456650@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084557.945845710@linuxfoundation.org> References: <20221123084557.945845710@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Alban Crequy commit 8678ea06852cd1f819b870c773d43df888d15d46 upstream. If a page fault occurs while copying the first byte, this function resets one byte before dst. As a consequence, an address could be modified and leaded to kernel crashes if case the modified address was accessed later. Fixes: b58294ead14c ("maccess: allow architectures to provide kernel probing directly") Signed-off-by: Alban Crequy Signed-off-by: Andrii Nakryiko Tested-by: Francis Laniel Reviewed-by: Andrew Morton Cc: [5.8] Link: https://lore.kernel.org/bpf/20221110085614.111213-2-albancrequy@linux.microsoft.com Signed-off-by: Greg Kroah-Hartman --- mm/maccess.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/maccess.c +++ b/mm/maccess.c @@ -83,7 +83,7 @@ long strncpy_from_kernel_nofault(char *d return src - unsafe_addr; Efault: pagefault_enable(); - dst[-1] = '\0'; + dst[0] = '\0'; return -EFAULT; } #else /* HAVE_GET_KERNEL_NOFAULT */