From patchwork Mon Mar 14 17:53:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sam James X-Patchwork-Id: 51960 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 423A4385840D for ; Mon, 14 Mar 2022 17:56:32 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 423A4385840D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1647280592; bh=NwmptmpOOjvypW/KS/UK2vUeCNZgrtQRLg+Dhe1IyqU=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=jC2mox+cvFQvBVqF5xK3cKgZ340trR/08NE8UetP/Fce8kLte0YL7kKSaD0Sf5OdU 4DVL3X1Mji4TaX/ZcKHzaPayr4++9ROYgqcPiEztdFG320RVoyuzP/foqqF0SFiSTA x27DjWmHf4H1n8Rl+8wFuP5Mf5ntA6wpVzjKojvo= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from smtp.gentoo.org (woodpecker.gentoo.org [140.211.166.183]) by sourceware.org (Postfix) with ESMTP id 2A30C3857C48 for ; Mon, 14 Mar 2022 17:56:08 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 2A30C3857C48 To: libc-alpha@sourceware.org Subject: [PATCH v2 1/1] nss: return early in DB reload-and-get if newfstatat fails (BZ #28752) Date: Mon, 14 Mar 2022 17:53:16 +0000 Message-Id: <20220314175316.3239120-2-sam@gentoo.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220314175316.3239120-1-sam@gentoo.org> References: <20220314175316.3239120-1-sam@gentoo.org> MIME-Version: 1.0 X-Spam-Status: No, score=-10.2 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_PASS, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Sam James via Libc-alpha From: Sam James Reply-To: Sam James Cc: mozilla@gentoo.org, toolchain@gentoo.org Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" In some circumstances, the __stat64_time64() call in nss_database_check_reload_and_get() might fail (via e.g. newfstatat being filtered by seccomp in parent). We have to check its return value to avoid an out of bounds access later on if the call failed. This manifests as Firefox crashing at runtime when e.g. glib is compiled with FAM support, which ends up taking this NSS path. Bug: https://sourceware.org/pipermail/libc-help/2021-December/006061.html Bug: https://bugs.gentoo.org/828070 Suggested-by: Adhemerval Zanella Signed-off-by: Sam James --- nss/nss_database.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/nss/nss_database.c b/nss/nss_database.c index d56c5b798d..a0522ea7d2 100644 --- a/nss/nss_database.c +++ b/nss/nss_database.c @@ -424,17 +424,21 @@ nss_database_check_reload_and_get (struct nss_database_state *local, errors here are very unlikely, but the chance that we're entering a container is also very unlikely, so we err on the side of both very unlikely things not happening at the same time. */ - if (__stat64_time64 ("/", &str) != 0 - || (local->root_ino != 0 - && (str.st_ino != local->root_ino - || str.st_dev != local->root_dev))) - { + if (__stat64_time64 ("/", &str) != 0) { + __libc_lock_unlock (local->lock); + return false; + } + + if (local->root_ino != 0 && (str.st_ino != local->root_ino + || str.st_dev != local->root_dev)) + { /* Change detected; disable reloading and return current state. */ atomic_store_release (&local->data.reload_disabled, 1); *result = local->data.services[database_index]; __libc_lock_unlock (local->lock); return true; } + local->root_ino = str.st_ino; local->root_dev = str.st_dev; __libc_lock_unlock (local->lock);