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 CD30F43F0B3; Mon, 31 Aug 2026 14:01:06 +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=1788184867; cv=none; b=L4/LYqvINFJlqCY3Zhwn9sgH3VTlF3Tkbsm+hwDhUfX0QyA+d4AFeYTqm6P40x1SMKNIduft94pTT0S0xDfQfa3dCEvPkHUhyNT4VF8Z90RjNh2Rcfz7uK2Q5mM2YzaJrZhaN6MhnQXFHwtcvy/wwvQ6ISE6zJdM2VnVq4Vrrmk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788184867; c=relaxed/simple; bh=hcV962f0xL8PYT903ThPZpoWdUCfYLVUoaeT5ET1sqQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QsyhaHo9BzjNHKx9+lvbxRjUu59Rggsl1g/uMBCeZv/oKQBSgLp3DZlOCcZm0J0demaxS/hGIR4BCxF5nr0Zjol9ATeWi/rvnNaqbgoMu7mzDb17PFuJAh4QR+noZqEouX6v4+Dj90cnwaMm6I1bctpgqDIJfNT9sGp0IrVYpcM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=WKFwxBBS; 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="WKFwxBBS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD52E1F000E9; Mon, 31 Aug 2026 14:01:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788184866; bh=KHXpQAHFad/+zd7z6AB5g1ncurKiKW6gZ5wWG+grRT4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=WKFwxBBSGOJtsXyEpPUmDyjyDkd4wkPlnbgza2QkcE7OX1yvNlf+S1hAVWbcPmHmn xUaZYKJV1A2BHDaNs2VWHyQrzLR1RA6hDDWBOB3liOa5JOkSzBzB95f+gFiegcsx68 /RJdWlaXCxnmonpYJo10yaEnBquUm21iMxp4pcmk= 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 6.1 27/92] riscv: Fix register corruption from uninitialized cregs on error Date: Mon, 31 Aug 2026 15:34:25 +0200 Message-ID: <20260831133401.060530343@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260831133359.482388899@linuxfoundation.org> References: <20260831133359.482388899@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 6.1-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 2ae8280ae4759..4be6fa82453aa 100644 --- a/arch/riscv/kernel/ptrace.c +++ b/arch/riscv/kernel/ptrace.c @@ -291,8 +291,8 @@ 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