From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 D7C965398C8; Mon, 31 Aug 2026 13:45:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788183931; cv=none; b=R2c14jdH/f0XFpHxUeptLedFr7drxgkO5vKTzYO6AeSHOL6LHXCM7NPTL1e6UsufZo5mcuKe1MVcRxRqeblYCPzlKztNaiTShYWIKbdTr5j7uJeNzDf94Il0JTO4GvxWffqeZxkla3qRfKHhh409qyhHb0HUdgAw8S6SgE6uhpE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788183931; c=relaxed/simple; bh=56ksBMN5zF9z9I2+ENumqnmmJndRSHmjB7wKq51E6sw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XVJsdfe4U6fVrNu/7/Pd6+9JobPvpRiydyXOON7hUGvj9nolOPpLzYEBS06lPzp21I7vJyi/ZRX4wwvOWkwNPAFS4Gl/2hBh8Dd6xik/xhLxavwaW1IP169VckPNMx4Y8ohG2cdv2aHQ7LNfsXeUbSQtet+x3+DPnONfQpp7QqM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=F9tpkLRJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="F9tpkLRJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF6111F00A3D; Mon, 31 Aug 2026 13:45:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788183929; bh=sHbcAgf5+OhDpjsltjbnRmIOwIBzbOblVUSnhA/L3NQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=F9tpkLRJ1cLh92NoAiN88/866wD8ZBm23+aVqvgkmewI670f/FngDz6ZMjuPykqSN whAKdxYFthduGCHW/DIMxYt2Y+y4mYQf1RvGW7t/wig8vIhRp/uc8T7QI2MkigX43P iuX6iFocpOnEXh6PrMqnbh/OKRlt47LVUwX92+js= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michael Neuling , Paul Walmsley , Sasha Levin Subject: [PATCH 6.18 15/83] riscv: Fix register corruption from uninitialized cregs on error Date: Mon, 31 Aug 2026 15:33:51 +0200 Message-ID: <20260831133359.994110063@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260831133359.207714926@linuxfoundation.org> References: <20260831133359.207714926@linuxfoundation.org> User-Agent: quilt/0.69 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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Neuling [ Upstream commit 6ebcbb53fc9bc30843054ed99fd60b8e542628f4 ] compat_riscv_gpr_set() calls cregs_to_regs() unconditionally, even when user_regset_copyin() fails. Since cregs is an uninitialized stack variable, a copyin failure causes uninitialized stack data to be written into the target task's pt_regs, corrupting its register state and potentially leaking kernel stack contents. compat_restore_sigcontext() has the same issue: it calls cregs_to_regs() even when __copy_from_user() fails, leading to the same corruption of the signal-returning task's register state on error. Only call cregs_to_regs() when the user copy succeeds. Fixes: 4608c159594f ("riscv: compat: ptrace: Add compat_arch_ptrace implement") Fixes: 7383ee05314b ("riscv: compat: signal: Add rt_frame implementation") Signed-off-by: Michael Neuling Assisted-by: Cursor:claude-4.6-opus-high-thinking Link: https://patch.msgid.link/20260501062320.2339562-1-mikey@neuling.org Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin --- arch/riscv/kernel/compat_signal.c | 2 ++ arch/riscv/kernel/ptrace.c | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/compat_signal.c b/arch/riscv/kernel/compat_signal.c index 6ec4e34255a9a..cf3eb33a11e46 100644 --- a/arch/riscv/kernel/compat_signal.c +++ b/arch/riscv/kernel/compat_signal.c @@ -107,6 +107,8 @@ static long compat_restore_sigcontext(struct pt_regs *regs, /* sc_regs is structured the same as the start of pt_regs */ err = __copy_from_user(&cregs, &sc->sc_regs, sizeof(sc->sc_regs)); + if (unlikely(err)) + return err; cregs_to_regs(&cregs, regs); diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c index 8e86305831ea4..32cd48a4cebb8 100644 --- a/arch/riscv/kernel/ptrace.c +++ b/arch/riscv/kernel/ptrace.c @@ -372,8 +372,8 @@ static int compat_riscv_gpr_set(struct task_struct *target, struct compat_user_regs_struct cregs; ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &cregs, 0, -1); - - cregs_to_regs(&cregs, task_pt_regs(target)); + if (!ret) + cregs_to_regs(&cregs, task_pt_regs(target)); return ret; } -- 2.53.0