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 7C4B9C4332F for ; Mon, 14 Nov 2022 12:53:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237468AbiKNMxH (ORCPT ); Mon, 14 Nov 2022 07:53:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45458 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237466AbiKNMxG (ORCPT ); Mon, 14 Nov 2022 07:53:06 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 200AE252B5 for ; Mon, 14 Nov 2022 04:53:05 -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 BD798B80EBC for ; Mon, 14 Nov 2022 12:53:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16107C433C1; Mon, 14 Nov 2022 12:53:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1668430382; bh=s2Aja3Zlk1oYU412sCWCYubleI2enra5LK8grBc+kH0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BFK6EFTkx9Ch8KRoNY/ZMNoG4I10YSlXiREr9el4BoRfmYrDK88H9zxv0LnxYZb2X C4HjzDBVUoHPhfg7TwqyRQmy1J7RYIvL5yfA6kJbW6nt7QkWjeg4D+7pPxdQtI5CHs V1LBmBpncEo3ajuYY07EJL6rehwYvFU1Lf+0s8DM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhengchao Shao , Kees Cook , Daniel Borkmann , Bill Wendling , Lorenz Bauer , Sasha Levin Subject: [PATCH 5.15 013/131] bpf, verifier: Fix memory leak in array reallocation for stack state Date: Mon, 14 Nov 2022 13:44:42 +0100 Message-Id: <20221114124449.295365530@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221114124448.729235104@linuxfoundation.org> References: <20221114124448.729235104@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: Kees Cook [ Upstream commit 42378a9ca55347102bbf86708776061d8fe3ece2 ] If an error (NULL) is returned by krealloc(), callers of realloc_array() were setting their allocation pointers to NULL, but on error krealloc() does not touch the original allocation. This would result in a memory resource leak. Instead, free the old allocation on the error handling path. The memory leak information is as follows as also reported by Zhengchao: unreferenced object 0xffff888019801800 (size 256): comm "bpf_repo", pid 6490, jiffies 4294959200 (age 17.170s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000b211474b>] __kmalloc_node_track_caller+0x45/0xc0 [<0000000086712a0b>] krealloc+0x83/0xd0 [<00000000139aab02>] realloc_array+0x82/0xe2 [<00000000b1ca41d1>] grow_stack_state+0xfb/0x186 [<00000000cd6f36d2>] check_mem_access.cold+0x141/0x1341 [<0000000081780455>] do_check_common+0x5358/0xb350 [<0000000015f6b091>] bpf_check.cold+0xc3/0x29d [<000000002973c690>] bpf_prog_load+0x13db/0x2240 [<00000000028d1644>] __sys_bpf+0x1605/0x4ce0 [<00000000053f29bd>] __x64_sys_bpf+0x75/0xb0 [<0000000056fedaf5>] do_syscall_64+0x35/0x80 [<000000002bd58261>] entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: c69431aab67a ("bpf: verifier: Improve function state reallocation") Reported-by: Zhengchao Shao Reported-by: Kees Cook Signed-off-by: Kees Cook Signed-off-by: Daniel Borkmann Reviewed-by: Bill Wendling Cc: Lorenz Bauer Link: https://lore.kernel.org/bpf/20221029025433.2533810-1-keescook@chromium.org Signed-off-by: Sasha Levin --- kernel/bpf/verifier.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c3a4158e838e..259248306056 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -770,12 +770,17 @@ static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t */ static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size) { + void *new_arr; + if (!new_n || old_n == new_n) goto out; - arr = krealloc_array(arr, new_n, size, GFP_KERNEL); - if (!arr) + new_arr = krealloc_array(arr, new_n, size, GFP_KERNEL); + if (!new_arr) { + kfree(arr); return NULL; + } + arr = new_arr; if (new_n > old_n) memset(arr + old_n * size, 0, (new_n - old_n) * size); -- 2.35.1