Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@suse.de>,
        Andy Lutomirski <luto@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 108/149] x86/fpu: Limit xstate copy size in xstateregs_set()
Date:   Mon, 19 Jul 2021 16:53:36 +0200
Message-Id: <20210719144926.921367488@linuxfoundation.org>
In-Reply-To: <20210719144901.370365147@linuxfoundation.org>
References: <20210719144901.370365147@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Thomas Gleixner <tglx@linutronix.de>

[ Upstream commit 07d6688b22e09be465652cf2da0da6bf86154df6 ]

If the count argument is larger than the xstate size, this will happily
copy beyond the end of xstate.

Fixes: 91c3dba7dbc1 ("x86/fpu/xstate: Fix PTRACE frames for XSAVES")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121452.120741557@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kernel/fpu/regset.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index d652b939ccfb..68e1fb66e701 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -124,7 +124,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
 	/*
 	 * A whole standard-format XSAVE buffer is needed:
 	 */
-	if ((pos != 0) || (count < fpu_user_xstate_size))
+	if (pos != 0 || count != fpu_user_xstate_size)
 		return -EFAULT;
 
 	xsave = &fpu->state.xsave;
-- 
2.30.2