From mboxrd@z Thu Jan 1 00:00:00 1970 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 CDA9717DFF3 for ; Fri, 30 Aug 2024 10:53:20 +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=1725015200; cv=none; b=lRfPCU+wJIbMDuJT+HzDo6/1g5YrNfacnxO+MnqUKMEogKOXoC5OpKP47hjxLnGvAIuFQv3HOyju7te3UjlsxnlKvvXoU9Do8c4f/6C/Xkgx+s5J2XqcZxq/E+VxnK59xq4BllbIGKNIA6dEmMkh60aX8Dju/4/sOvtCvhMv3UU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725015200; c=relaxed/simple; bh=wuC/ae7LVc2SZ3hYojSzlrzdwwkplCv9ECq3pWrFmVw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lsekEyz0c6A0ClFG6WUpOCq7/sp/dVVRcQKBLBkEhdbgVHUuQByjhUCOZrkRNB4Wl/Re8pb/UlQDLT50ECSMd0C9mntzavhCMn5B3cJWFjekOIxr6nOHGjKUfwEjWu+/OuevlbBT8uk22EBjKfOdw00umgl7XdZqYSGgbW8MN7o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ioY2orQ/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ioY2orQ/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C788FC4CEC2; Fri, 30 Aug 2024 10:53:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725015200; bh=wuC/ae7LVc2SZ3hYojSzlrzdwwkplCv9ECq3pWrFmVw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ioY2orQ/cZ9E7KTEgVonjJxRdtbUf48MIrE/LKk4WcRWJFDn9F/I4qHQslyC4/w7v y8fhieCeyoWiFRCpbk6l4LK0jeNfXD2SJ/z28BuIvGPnXNODl40m9TqqtIlFEXFuWz Aeye4atTa72j5LUPiaJyD+QBBxOgwrQfam0NfgLQ= Date: Fri, 30 Aug 2024 12:53:17 +0200 From: Greg Kroah-Hartman To: Shung-Hsi Yu Cc: cve@kernel.org, linux-kernel@vger.kernel.org, Eduard Zingerman , Andrii Nakryiko , Alexei Starovoitov Subject: Re: CVE-2024-43910: bpf: add missing check_func_arg_reg_off() to prevent out-of-bounds memory accesses Message-ID: <2024083051-parasite-unsaved-6e19@gregkh> References: <2024082630-CVE-2024-43910-c6ec@gregkh> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed, Aug 28, 2024 at 06:50:32PM +0800, Shung-Hsi Yu wrote: > On Mon, Aug 26, 2024 at 12:17:18PM GMT, Greg Kroah-Hartman wrote: > > Description > > =========== > > > > In the Linux kernel, the following vulnerability has been resolved: > > > > bpf: add missing check_func_arg_reg_off() to prevent out-of-bounds memory accesses > > > > Currently, it's possible to pass in a modified CONST_PTR_TO_DYNPTR to > > a global function as an argument. The adverse effects of this is that > > BPF helpers can continue to make use of this modified > > CONST_PTR_TO_DYNPTR from within the context of the global function, > > which can unintentionally result in out-of-bounds memory accesses and > > therefore compromise overall system stability i.e. > > > > [ 244.157771] BUG: KASAN: slab-out-of-bounds in bpf_dynptr_data+0x137/0x140 > > [ 244.161345] Read of size 8 at addr ffff88810914be68 by task test_progs/302 > > [ 244.167151] CPU: 0 PID: 302 Comm: test_progs Tainted: G O E 6.10.0-rc3-00131-g66b586715063 #533 > > [ 244.174318] Call Trace: > > [ 244.175787] > > [ 244.177356] dump_stack_lvl+0x66/0xa0 > > [ 244.179531] print_report+0xce/0x670 > > [ 244.182314] ? __virt_addr_valid+0x200/0x3e0 > > [ 244.184908] kasan_report+0xd7/0x110 > > [ 244.187408] ? bpf_dynptr_data+0x137/0x140 > > [ 244.189714] ? bpf_dynptr_data+0x137/0x140 > > [ 244.192020] bpf_dynptr_data+0x137/0x140 > > [ 244.194264] bpf_prog_b02a02fdd2bdc5fa_global_call_bpf_dynptr_data+0x22/0x26 > > [ 244.198044] bpf_prog_b0fe7b9d7dc3abde_callback_adjust_bpf_dynptr_reg_off+0x1f/0x23 > > [ 244.202136] bpf_user_ringbuf_drain+0x2c7/0x570 > > [ 244.204744] ? 0xffffffffc0009e58 > > [ 244.206593] ? __pfx_bpf_user_ringbuf_drain+0x10/0x10 > > [ 244.209795] bpf_prog_33ab33f6a804ba2d_user_ringbuf_callback_const_ptr_to_dynptr_reg_off+0x47/0x4b > > [ 244.215922] bpf_trampoline_6442502480+0x43/0xe3 > > [ 244.218691] __x64_sys_prlimit64+0x9/0xf0 > > [ 244.220912] do_syscall_64+0xc1/0x1d0 > > [ 244.223043] entry_SYSCALL_64_after_hwframe+0x77/0x7f > > [ 244.226458] RIP: 0033:0x7ffa3eb8f059 > > [ 244.228582] Code: 08 89 e8 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8f 1d 0d 00 f7 d8 64 89 01 48 > > [ 244.241307] RSP: 002b:00007ffa3e9c6eb8 EFLAGS: 00000206 ORIG_RAX: 000000000000012e > > [ 244.246474] RAX: ffffffffffffffda RBX: 00007ffa3e9c7cdc RCX: 00007ffa3eb8f059 > > [ 244.250478] RDX: 00007ffa3eb162b4 RSI: 0000000000000000 RDI: 00007ffa3e9c7fb0 > > [ 244.255396] RBP: 00007ffa3e9c6ed0 R08: 00007ffa3e9c76c0 R09: 0000000000000000 > > [ 244.260195] R10: 0000000000000000 R11: 0000000000000206 R12: ffffffffffffff80 > > [ 244.264201] R13: 000000000000001c R14: 00007ffc5d6b4260 R15: 00007ffa3e1c7000 > > [ 244.268303] > > > > Add a check_func_arg_reg_off() to the path in which the BPF verifier > > verifies the arguments of global function arguments, specifically > > those which take an argument of type ARG_PTR_TO_DYNPTR | > > MEM_RDONLY. Also, process_dynptr_func() doesn't appear to perform any > > explicit and strict type matching on the supplied register type, so > > let's also enforce that a register either type PTR_TO_STACK or > > CONST_PTR_TO_DYNPTR is by the caller. > > > > The Linux kernel CVE team has assigned CVE-2024-43910 to this issue. > > > > > > Affected and fixed versions > > =========================== > > > > Fixed in 6.10.5 with commit 13663a7c644b > > Fixed in 6.11-rc1 with commit ec2b9a5e11e5 > > I believe the issue of being able to pass modified (i.e. non-zero > offset) dynptr to global function was introduced with commit > a64bfe618665 ("bpf: add support for passing dynptr pointer to global > subprog") in 6.8. Thanks for the info, I've marked this as the "vulnerable" commit now in the cve and updated the json record for it. thanks for the review! greg k-h