From patchwork Tue Jul 2 00:58:26 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 13718769 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 9A69E6FC3 for ; Tue, 2 Jul 2024 00:58:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719881906; cv=none; b=QYACl1CSj0EmUYj0eitHzFUhP6G3nYtmdc4f5gGpkMNvSDuQluC47OCuZBRxHPQHuF+zPsu/QA+56BDE7JPCu831PnOvo9acJ2WJYlx0cidpOnVteqKmEhUl9NZNXE5SuuN5etNe7VD9HB8LkIlVqJY6Qn+kP2IjlpoN+f5wzg4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719881906; c=relaxed/simple; bh=YGF71p9bHkNTZoBkDGTz041KCYInXLTRWSBsCuocVbI=; h=Date:Subject:From:To:Cc:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=A4ufPH4aAhXWS/yHsw6+BqYdaVIY7taZZE1doA77ka2JBIOXQZ+iuLL/T9ySIcvGD/cTPFgv1IVkPlc4fLUFISzCC+tMtNIAI6G2pbs4zRqHOTiS75NoOVvClnj5OaBMTZcD6WSwq5NIeXoaRtvJQG9GDCEY/tCrdGS6zYWkYO0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=otOWjFGn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="otOWjFGn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 766ABC116B1; Tue, 2 Jul 2024 00:58:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719881906; bh=YGF71p9bHkNTZoBkDGTz041KCYInXLTRWSBsCuocVbI=; h=Date:Subject:From:To:Cc:In-Reply-To:References:From; b=otOWjFGnmgl7nL4g4QrKoVW8Uxc1FWNLaczOiullhV5O2WVXBcoRcN27w71TRaUU3 c3fMHYZ+aSMOpqa8RlQT4sGhiD3yqLzIdFfXiKHbxfLycT4rBf644VeuTF8qUZLD/c i7isXW0mBZMyIqZRlQ3u7n9+ECPzUbFxZL0l1pdaOSOEtIZzzVOc9nblQutul77ew4 QX1S+sHeTBUL/RxNeMnLzwuuz4sP4e6qz1by9JoQOXVonHOwX4AvpcwJSeTzu4OykI BylSHe39r1oyzG5eUQnxeHdwa+jkkmh5y35DZKa1pCjdd2ctV5vDq9JYiw/OJzb3R3 MLqqR5vvS9h7A== Date: Mon, 01 Jul 2024 17:58:26 -0700 Subject: [PATCH 04/13] xfs_scrub: avoid potential UAF after freeing a duplicate name entry From: "Darrick J. Wong" To: djwong@kernel.org, cem@kernel.org Cc: linux-xfs@vger.kernel.org, hch@lst.de Message-ID: <171988117673.2007123.15647994096603486811.stgit@frogsfrogsfrogs> In-Reply-To: <171988117591.2007123.4966781934074641923.stgit@frogsfrogsfrogs> References: <171988117591.2007123.4966781934074641923.stgit@frogsfrogsfrogs> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Darrick J. Wong Change the function declaration of unicrash_add to set the caller's @new_entry to NULL if we detect an updated name entry and do not wish to continue processing. This avoids a theoretical UAF if the unicrash_add caller were to accidentally continue using the pointer. This isn't an /actual/ UAF because the function formerly set @badflags to zero, but let's be a little defensive. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- scrub/unicrash.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/scrub/unicrash.c b/scrub/unicrash.c index fc1adb2caab7..5a61d69705bd 100644 --- a/scrub/unicrash.c +++ b/scrub/unicrash.c @@ -626,10 +626,11 @@ _("Unicode name \"%s\" in %s could be confused with \"%s\"."), static void unicrash_add( struct unicrash *uc, - struct name_entry *new_entry, + struct name_entry **new_entryp, unsigned int *badflags, struct name_entry **existing_entry) { + struct name_entry *new_entry = *new_entryp; struct name_entry *entry; size_t bucket; xfs_dahash_t hash; @@ -652,7 +653,7 @@ unicrash_add( entry->ino = new_entry->ino; uc->buckets[bucket] = new_entry->next; name_entry_free(new_entry); - *badflags = 0; + *new_entryp = NULL; return; } @@ -695,8 +696,8 @@ __unicrash_check_name( return 0; name_entry_examine(new_entry, &badflags); - unicrash_add(uc, new_entry, &badflags, &dup_entry); - if (badflags) + unicrash_add(uc, &new_entry, &badflags, &dup_entry); + if (new_entry && badflags) unicrash_complain(uc, dsc, namedescr, new_entry, badflags, dup_entry);