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 42D9A436BEA; Mon, 31 Aug 2026 13:55:08 +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=1788184509; cv=none; b=kNazuJhpLgpLphDfwwmdq0AXeqFJ7lsrP0NQ19+iiUQ1IIiT2bhiJteGYEru4+niRou/FobxN1mJ+Vq3bts9XRS/f6+yfwgmL4ufhMVAGrA9XsDmvI3FCVjLXT72gnYEhmZPpGYO3oyAEW4RGDkqMHa4kzGvl3vhw2sI3T58s9k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788184509; c=relaxed/simple; bh=STy5Ld5IlTbpjZGA+cZgFPft35l46CD9GrvtwUC8Gcc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aVoV4HvNRwC5EEylk/QT3FTIM7BKZRdUJAgBTd2Ce3OW8wM57HKtnlaG+U1RYnOypGLHEEe612kAu8FN0HzEeUorDzp9fz/GZAenivgU5jQp2RbkTqCxNH3J3BiqGka/VM+rjFiaYOhp8AOSZ39pO9PLoRfp4KfFkNPwCU/ZFoY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gZCd50NF; 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="gZCd50NF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9396A1F00A3D; Mon, 31 Aug 2026 13:55:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788184508; bh=wJEaMsW02Q1U+XkVtzQ1bj3/CElSEjz3hAducyTauoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gZCd50NFiy8leQfj+nvk1YEUgygZ/I/b7jEGMpwCos2H8LVKipauioFANzLZnMt06 Bo/PpZm6orMzuEg9u1lnaJqQeU/TyvUUQlwBaVRd/2WYN6hdVJd/ewaCpLNrv+pWjq zvLHGg8UTU+3juGf7fH9knYKPL9skyVdgVw2Ee/4= 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 6.6 25/91] riscv: Fix register corruption from uninitialized cregs on error Date: Mon, 31 Aug 2026 15:34:13 +0200 Message-ID: <20260831133400.962961439@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260831133359.468089036@linuxfoundation.org> References: <20260831133359.468089036@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 6.6-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 2afe460de16a6..be412db2ba1f3 100644 --- a/arch/riscv/kernel/ptrace.c +++ b/arch/riscv/kernel/ptrace.c @@ -327,8 +327,8 @@ 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