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 4363A3FB1B; Mon, 23 Jun 2025 22:03:36 +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=1750716216; cv=none; b=IUnvX3sURittvNP0/LZiAgVKekOivqzSt7azreCaO1bRokykywkwVySTl5AqC6x1SKg4qsCAKwzAIyb0gEnz2jIakGKu0Cg1pPiHEzzYTCyEjqEF+UVglM7AhqQzp3nJARdvhuarJldnneZ7hewos2KPVi9rIj+BPN3M+jQ/2EA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750716216; c=relaxed/simple; bh=LPNtnEzh+N68tk6yVhyNmEF+vf2m6UufcV0iAxNneUA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H5PHNWz9Sk3P/7huSIaYQBhZZ0COEq/ZdKQMlqxcJs5zbFgEw8GjSD4otRYWxhsS8llPl5kBwFLmmtVsnzcQI6WyNK3VuYRzLm150DpzNBbZl3dVjxh/+Rba06yyYxIXN+GXWl/0GUPAW6n+7ZV0yMGsOgJ4ui4RB3P+9kAW6TU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fP2PNlbo; 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="fP2PNlbo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0029C4CEEA; Mon, 23 Jun 2025 22:03:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750716216; bh=LPNtnEzh+N68tk6yVhyNmEF+vf2m6UufcV0iAxNneUA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fP2PNlborvwPGY81iknyhee6p/Os3D6QMTk6aXkF1Ragbeu9US1LNdPnZEAzqxb7t aZ+o/f8E15tpj2s1NcdnLDpj449VApKQsSBWCl42UlKg+kW22ilA6rdrIFMZ+KQ/Be gGLfAZnifCZzWM/FeuVkkbGtkfKzoN6A1b+RnsbA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tengda Wu , Will Deacon , Sasha Levin Subject: [PATCH 5.10 355/355] arm64/ptrace: Fix stack-out-of-bounds read in regs_get_kernel_stack_nth() Date: Mon, 23 Jun 2025 15:09:16 +0200 Message-ID: <20250623130637.386447965@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250623130626.716971725@linuxfoundation.org> References: <20250623130626.716971725@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tengda Wu [ Upstream commit 39dfc971e42d886e7df01371cd1bef505076d84c ] KASAN reports a stack-out-of-bounds read in regs_get_kernel_stack_nth(). Call Trace: [ 97.283505] BUG: KASAN: stack-out-of-bounds in regs_get_kernel_stack_nth+0xa8/0xc8 [ 97.284677] Read of size 8 at addr ffff800089277c10 by task 1.sh/2550 [ 97.285732] [ 97.286067] CPU: 7 PID: 2550 Comm: 1.sh Not tainted 6.6.0+ #11 [ 97.287032] Hardware name: linux,dummy-virt (DT) [ 97.287815] Call trace: [ 97.288279] dump_backtrace+0xa0/0x128 [ 97.288946] show_stack+0x20/0x38 [ 97.289551] dump_stack_lvl+0x78/0xc8 [ 97.290203] print_address_description.constprop.0+0x84/0x3c8 [ 97.291159] print_report+0xb0/0x280 [ 97.291792] kasan_report+0x84/0xd0 [ 97.292421] __asan_load8+0x9c/0xc0 [ 97.293042] regs_get_kernel_stack_nth+0xa8/0xc8 [ 97.293835] process_fetch_insn+0x770/0xa30 [ 97.294562] kprobe_trace_func+0x254/0x3b0 [ 97.295271] kprobe_dispatcher+0x98/0xe0 [ 97.295955] kprobe_breakpoint_handler+0x1b0/0x210 [ 97.296774] call_break_hook+0xc4/0x100 [ 97.297451] brk_handler+0x24/0x78 [ 97.298073] do_debug_exception+0xac/0x178 [ 97.298785] el1_dbg+0x70/0x90 [ 97.299344] el1h_64_sync_handler+0xcc/0xe8 [ 97.300066] el1h_64_sync+0x78/0x80 [ 97.300699] kernel_clone+0x0/0x500 [ 97.301331] __arm64_sys_clone+0x70/0x90 [ 97.302084] invoke_syscall+0x68/0x198 [ 97.302746] el0_svc_common.constprop.0+0x11c/0x150 [ 97.303569] do_el0_svc+0x38/0x50 [ 97.304164] el0_svc+0x44/0x1d8 [ 97.304749] el0t_64_sync_handler+0x100/0x130 [ 97.305500] el0t_64_sync+0x188/0x190 [ 97.306151] [ 97.306475] The buggy address belongs to stack of task 1.sh/2550 [ 97.307461] and is located at offset 0 in frame: [ 97.308257] __se_sys_clone+0x0/0x138 [ 97.308910] [ 97.309241] This frame has 1 object: [ 97.309873] [48, 184) 'args' [ 97.309876] [ 97.310749] The buggy address belongs to the virtual mapping at [ 97.310749] [ffff800089270000, ffff800089279000) created by: [ 97.310749] dup_task_struct+0xc0/0x2e8 [ 97.313347] [ 97.313674] The buggy address belongs to the physical page: [ 97.314604] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14f69a [ 97.315885] flags: 0x15ffffe00000000(node=1|zone=2|lastcpupid=0xfffff) [ 97.316957] raw: 015ffffe00000000 0000000000000000 dead000000000122 0000000000000000 [ 97.318207] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 [ 97.319445] page dumped because: kasan: bad access detected [ 97.320371] [ 97.320694] Memory state around the buggy address: [ 97.321511] ffff800089277b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 97.322681] ffff800089277b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 97.323846] >ffff800089277c00: 00 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 00 00 00 [ 97.325023] ^ [ 97.325683] ffff800089277c80: 00 00 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 f3 f3 [ 97.326856] ffff800089277d00: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 This issue seems to be related to the behavior of some gcc compilers and was also fixed on the s390 architecture before: commit d93a855c31b7 ("s390/ptrace: Avoid KASAN false positives in regs_get_kernel_stack_nth()") As described in that commit, regs_get_kernel_stack_nth() has confirmed that `addr` is on the stack, so reading the value at `*addr` should be allowed. Use READ_ONCE_NOCHECK() helper to silence the KASAN check for this case. Fixes: 0a8ea52c3eb1 ("arm64: Add HAVE_REGS_AND_STACK_ACCESS_API feature") Signed-off-by: Tengda Wu Link: https://lore.kernel.org/r/20250604005533.1278992-1-wutengda@huaweicloud.com [will: Use '*addr' as the argument to READ_ONCE_NOCHECK()] Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 6c9e7662c07f7..5d52eac22d831 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -140,7 +140,7 @@ unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n) addr += n; if (regs_within_kernel_stack(regs, (unsigned long)addr)) - return *addr; + return READ_ONCE_NOCHECK(*addr); else return 0; } -- 2.39.5