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 35BBC27814F; Tue, 22 Apr 2025 02:19:08 +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=1745288349; cv=none; b=ur/Au0cftMxM75elE/7D4VwDWr1aSuG0nbr6+E+aKaTOc/RJvm6x0s5USG7FTIWxHSxgMreV86Xaf4c6PW5v1fb2OK5loAEYI5GL/Jjn5utz+LyMX8h2qF6RZq7MMmtd3QqIV0hUOZIlPOdH7qxIcK76p6mq3paq3hsFj2vf4KQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745288349; c=relaxed/simple; bh=iv/M+G4FWbUb2I/9nG++kGHvAyggO8O8m+i+jsiKPss=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=t6NdgvdlcIuxd063nnPdFOZcxGbpoCGxDODkUusY+XlXaURvJjj+c0x8dJ/1+p0LtAugDyBsJzNLpkD8QX8WJt9LHBpUN02eqHbasj9WEMwUOez2KqKq7E7hmZt6fc3CPJvKUPmhzj6bre/hVGQhrQI3MJZu7+YB6pL301hzAdI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Js5jggHx; 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="Js5jggHx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86C10C4CEEC; Tue, 22 Apr 2025 02:19:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745288348; bh=iv/M+G4FWbUb2I/9nG++kGHvAyggO8O8m+i+jsiKPss=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Js5jggHxBaTEYOslCpWTlE6XQ0zimSZ9VuYYO397Ex3PiCRtAfC+m8Pe++uK5iceH XBmTzsbdy+prU+Q8bXwfbh/7weOzw510s7oidj37SxAEF8E/buA+emKSWmC6EL4eAt r+NP8XKROomFSNRQ+yLvriRrnT6u0bfG7UZZRwr/Di17heCmiLPXADM8foKFQCe2hI qiM0pKSHoACcpfEXK9TU7k5E0wLhldUNHf7D9JtVfjwgJ30QSD2bKBD78VrQ6mZfta BBeZuRECH+cxBLGHjxTh3vAAGRJloaE3s4ptXG3KLj+fl31JN+PO+MLw4v0hEYzXOF FcRFgASpkTMmA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nathan Chancellor , Alexandre Ghiti , "Dmitry V . Levin" , Sasha Levin , paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org Subject: [PATCH AUTOSEL 5.4 3/3] riscv: Avoid fortify warning in syscall_get_arguments() Date: Mon, 21 Apr 2025 22:19:02 -0400 Message-Id: <20250422021903.1942115-3-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250422021903.1942115-1-sashal@kernel.org> References: <20250422021903.1942115-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.4.292 Content-Transfer-Encoding: 8bit From: Nathan Chancellor [ Upstream commit 1413708f990cb7d025affd706ba9c23e2bfc1a27 ] When building with CONFIG_FORTIFY_SOURCE=y and W=1, there is a warning because of the memcpy() in syscall_get_arguments(): In file included from include/linux/string.h:392, from include/linux/bitmap.h:13, from include/linux/cpumask.h:12, from arch/riscv/include/asm/processor.h:55, from include/linux/sched.h:13, from kernel/ptrace.c:13: In function 'fortify_memcpy_chk', inlined from 'syscall_get_arguments.isra' at arch/riscv/include/asm/syscall.h:66:2: include/linux/fortify-string.h:580:25: error: call to '__read_overflow2_field' declared with attribute warning: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Werror=attribute-warning] 580 | __read_overflow2_field(q_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors The fortified memcpy() routine enforces that the source is not overread and the destination is not overwritten if the size of either field and the size of the copy are known at compile time. The memcpy() in syscall_get_arguments() intentionally overreads from a1 to a5 in 'struct pt_regs' but this is bigger than the size of a1. Normally, this could be solved by wrapping a1 through a5 with struct_group() but there was already a struct_group() applied to these members in commit bba547810c66 ("riscv: tracing: Fix __write_overflow_field in ftrace_partial_regs()"). Just avoid memcpy() altogether and write the copying of args from regs manually, which clears up the warning at the expense of three extra lines of code. Signed-off-by: Nathan Chancellor Reviewed-by: Alexandre Ghiti Reviewed-by: Dmitry V. Levin Link: https://lore.kernel.org/r/20250409-riscv-avoid-fortify-warning-syscall_get_arguments-v1-1-7853436d4755@kernel.org Signed-off-by: Alexandre Ghiti Signed-off-by: Sasha Levin --- arch/riscv/include/asm/syscall.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h index 42347d0981e7e..e53690b30bbeb 100644 --- a/arch/riscv/include/asm/syscall.h +++ b/arch/riscv/include/asm/syscall.h @@ -67,8 +67,11 @@ static inline void syscall_get_arguments(struct task_struct *task, unsigned long *args) { args[0] = regs->orig_a0; - args++; - memcpy(args, ®s->a1, 5 * sizeof(args[0])); + args[1] = regs->a1; + args[2] = regs->a2; + args[3] = regs->a3; + args[4] = regs->a4; + args[5] = regs->a5; } static inline void syscall_set_arguments(struct task_struct *task, -- 2.39.5