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x86/fpu: Reset state for all signal restore failures

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commit efa165504943f2128d50f63de0c02faf6dcceb0d upstream.

If access_ok() or fpregs_soft_set() fails in __fpu__restore_sig() then the
function just returns but does not clear the FPU state as it does for all
other fatal failures.

Clear the FPU state for these failures as well.

Fixes: 72a671ced66d ("x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/87mtryyhhz.ffs@nanos.tec.linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thomas Gleixner 2021-06-09 21:18:00 +02:00 committed by Sasha Levin
parent 68fed07258
commit 3267c5454e
1 changed files with 20 additions and 11 deletions
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31
arch/x86/kernel/fpu/signal.c
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@ -272,6 +272,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
int state_size = fpu_kernel_xstate_size;
u64 xfeatures = 0;
int fx_only = 0;
int ret = 0;
ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) ||
IS_ENABLED(CONFIG_IA32_EMULATION));
@ -281,15 +282,21 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
return 0;
}
if (!access_ok(VERIFY_READ, buf, size))
return -EACCES;
if (!access_ok(VERIFY_READ, buf, size)) {
ret = -EACCES;
goto out_err;
}
fpu__initialize(fpu);
if (!static_cpu_has(X86_FEATURE_FPU))
return fpregs_soft_set(current, NULL,
0, sizeof(struct user_i387_ia32_struct),
NULL, buf) != 0;
if (!static_cpu_has(X86_FEATURE_FPU)) {
ret = fpregs_soft_set(current, NULL,
0, sizeof(struct user_i387_ia32_struct),
NULL, buf) != 0;
if (ret)
goto out_err;
return 0;
}
if (use_xsave()) {
struct _fpx_sw_bytes fx_sw_user;
@ -349,6 +356,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
fpu__restore(fpu);
local_bh_enable();
/* Failure is already handled */
return err;
} else {
/*
@ -356,13 +364,14 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
* state to the registers directly (with exceptions handled).
*/
user_fpu_begin();
if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) {
fpu__clear(fpu);
return -1;
}
if (!copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only))
return 0;
ret = -1;
}
return 0;
out_err:
fpu__clear(fpu);
return ret;
}
static inline int xstate_sigframe_size(void)