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Message-Id: <9f48183def94d18babf484e8348c3fa054256246.1462983817.git.yu-cheng.yu@intel.com>
Date: Wed, 11 May 2016 12:51:13 -0700
From: Yu-cheng Yu <yu-cheng.yu@...el.com>
To: linux-kernel@...r.kernel.org, x86@...nel.org,
"H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>,
Andy Lutomirski <luto@...nel.org>,
Borislav Petkov <bp@...e.de>,
Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>,
"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
Fenghua Yu <fenghua.yu@...el.com>,
Yu-cheng Yu <yu-cheng.yu@...el.com>
Subject: [PATCH v7 10/13] x86/xsaves: Fix __fpu_restore_sig() for XSAVES
When the kernel is using XSAVES compacted format, we cannot do
__copy_from_user() from a signal frame, which has standard-format data.
Fix it by using copyin_to_xsaves(), which converts between formats and
filters out all supervisor states that we do not allow userspace to
write.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@...el.com>
Reviewed-by: Dave Hansen <dave.hansen@...el.com>
---
arch/x86/kernel/fpu/signal.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 9ce2963..abc96b2 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -321,8 +321,15 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
*/
fpu__drop(fpu);
- if (__copy_from_user(&fpu->state.xsave, buf_fx, state_size) ||
- __copy_from_user(&env, buf, sizeof(env))) {
+ if (using_compacted_format()) {
+ err = copyin_to_xsaves(NULL, buf_fx,
+ &fpu->state.xsave);
+ } else {
+ err = __copy_from_user(&fpu->state.xsave,
+ buf_fx, state_size);
+ }
+
+ if (err || __copy_from_user(&env, buf, sizeof(env))) {
fpstate_init(&fpu->state);
err = -1;
} else {
--
1.9.1
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