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 9AB0BEB64DD for ; Sun, 2 Jul 2023 19:38:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231144AbjGBTim (ORCPT ); Sun, 2 Jul 2023 15:38:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50726 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230426AbjGBTia (ORCPT ); Sun, 2 Jul 2023 15:38:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A6E0E69; Sun, 2 Jul 2023 12:38:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id EC31E60C75; Sun, 2 Jul 2023 19:38:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81774C433C9; Sun, 2 Jul 2023 19:38:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1688326706; bh=wDagCjtjaIj95OfrF51B+qxo5aNI1G/OqVnTP7Rn1QY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=og0C6Yc1P/w30wLX45b9RtXt6msdHdWeFqXrEMQ5LvfWzEAVwtHDA20Q/HSshNAl9 dbVzktcN/QrOBybfIxzFBkN6fk8KQzuEqHCkwzfu8Jh1Oc2dCiryXqsODT2423zxLb Z3RjWVtxSYnNMYIwd/Jn6jLrXxUagZCTKxJb9K8Lz+6jA9zEE9/GopVyWdCshp+Psc 88EVxx08yugIS5yocH6LTZ+qKgam0ZJrJbuExjvlyhP5MGabj4GothdA3Y54JQz6UU 2rpfIuqvfDNrzbP/cQ3q65f5/qO9dw2fRbUh+jkRyXfGSESZ+J7WeFHIunNy2Cjiq+ zsxkFy8pdXQ6A== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Prince Kumar Maurya , syzbot+aad58150cbc64ba41bdc@syzkaller.appspotmail.com, Christian Brauner , Sasha Levin , viro@zeniv.linux.org.uk, chenzhongjin@huawei.com, dchinner@redhat.com Subject: [PATCH AUTOSEL 6.4 05/16] fs/sysv: Null check to prevent null-ptr-deref bug Date: Sun, 2 Jul 2023 15:38:04 -0400 Message-Id: <20230702193815.1775684-5-sashal@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230702193815.1775684-1-sashal@kernel.org> References: <20230702193815.1775684-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.4.1 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Prince Kumar Maurya [ Upstream commit ea2b62f305893992156a798f665847e0663c9f41 ] sb_getblk(inode->i_sb, parent) return a null ptr and taking lock on that leads to the null-ptr-deref bug. Reported-by: syzbot+aad58150cbc64ba41bdc@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=aad58150cbc64ba41bdc Signed-off-by: Prince Kumar Maurya Message-Id: <20230531013141.19487-1-princekumarmaurya06@gmail.com> Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin --- fs/sysv/itree.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/sysv/itree.c b/fs/sysv/itree.c index b22764fe669c8..58d7f43a13712 100644 --- a/fs/sysv/itree.c +++ b/fs/sysv/itree.c @@ -145,6 +145,10 @@ static int alloc_branch(struct inode *inode, */ parent = block_to_cpu(SYSV_SB(inode->i_sb), branch[n-1].key); bh = sb_getblk(inode->i_sb, parent); + if (!bh) { + sysv_free_block(inode->i_sb, branch[n].key); + break; + } lock_buffer(bh); memset(bh->b_data, 0, blocksize); branch[n].bh = bh; -- 2.39.2