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 3D2DBCCA497 for ; Tue, 7 Jun 2022 19:53:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358264AbiFGTwS (ORCPT ); Tue, 7 Jun 2022 15:52:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352187AbiFGStK (ORCPT ); Tue, 7 Jun 2022 14:49:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D18D6206; Tue, 7 Jun 2022 11:03:11 -0700 (PDT) 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 CCF73B81F38; Tue, 7 Jun 2022 18:03:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C59ECC36AFF; Tue, 7 Jun 2022 18:03:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624988; bh=TJBhf9cCZntuUry2rBduhUC/L6MPgWTTHuECFdctN7Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lZ38ncLXEiPODxm029Q+gRe2wlfmU5gapmMzjsz/K/8DbKe7p7YioliVq++C33KWm hIBCZCwAFVLhqN+ZOw4WmJkVYA2Z9L/FPDb4Ynajlo1HHn/sNQzxGQdxyS5+XGPe9z 2KtB0WRcAF+0FJ17qQODV28jKCiLAsAHl7/zXYgYD/myGkpf4pFwIxnwpLLJ0+v8RN 13BZ/gtdhdrVg6sRSFlGCeG9YjY2MYTEaxVnlzL3t+SVE1303U78J0NMyrRSHnwkoJ q0naj9dQNyJnyAC0ogtvMp9Q5FLYIHtCWMKFVMjr98t+v1aVi0JNLk47FnUYP3dpI1 O2mpJzw+GX4CA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Masahiro Yamada , Nick Desaulniers , Sasha Levin , michal.lkml@markovi.net, linux-kbuild@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 21/25] modpost: fix undefined behavior of is_arm_mapping_symbol() Date: Tue, 7 Jun 2022 14:02:22 -0400 Message-Id: <20220607180229.482040-21-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607180229.482040-1-sashal@kernel.org> References: <20220607180229.482040-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Masahiro Yamada [ Upstream commit d6b732666a1bae0df3c3ae06925043bba34502b1 ] The return value of is_arm_mapping_symbol() is unpredictable when "$" is passed in. strchr(3) says: The strchr() and strrchr() functions return a pointer to the matched character or NULL if the character is not found. The terminating null byte is considered part of the string, so that if c is specified as '\0', these functions return a pointer to the terminator. When str[1] is '\0', strchr("axtd", str[1]) is not NULL, and str[2] is referenced (i.e. buffer overrun). Test code --------- char str1[] = "abc"; char str2[] = "ab"; strcpy(str1, "$"); strcpy(str2, "$"); printf("test1: %d\n", is_arm_mapping_symbol(str1)); printf("test2: %d\n", is_arm_mapping_symbol(str2)); Result ------ test1: 0 test2: 1 Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers Signed-off-by: Sasha Levin --- scripts/mod/modpost.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index b6eb929899c5..eaf82042f31c 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1229,7 +1229,8 @@ static int secref_whitelist(const struct sectioncheck *mismatch, static inline int is_arm_mapping_symbol(const char *str) { - return str[0] == '$' && strchr("axtd", str[1]) + return str[0] == '$' && + (str[1] == 'a' || str[1] == 'd' || str[1] == 't' || str[1] == 'x') && (str[2] == '\0' || str[2] == '.'); } -- 2.35.1