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x86/fpu: Reset state for all signal restore failures

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commit efa1655049 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: 72a671ced6 ("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 Greg Kroah-Hartman
parent 4f1e9bafa1
commit f3c629b164
1 changed files with 15 additions and 11 deletions
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26
arch/x86/kernel/fpu/signal.c
View file

@ -289,13 +289,17 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
return 0;
}
if (!access_ok(buf, size))
return -EACCES;
if (!access_ok(buf, size)) {
ret = -EACCES;
goto out;
}
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);
goto out;
}
if (use_xsave()) {
struct _fpx_sw_bytes fx_sw_user;
@ -333,7 +337,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
if (ia32_fxstate) {
ret = __copy_from_user(&env, buf, sizeof(env));
if (ret)
goto err_out;
goto out;
envp = &env;
} else {
/*
@ -369,7 +373,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
ret = validate_xstate_header(&fpu->state.xsave.header);
}
if (ret)
goto err_out;
goto out;
sanitize_restored_xstate(&fpu->state, envp, xfeatures, fx_only);
@ -382,7 +386,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
ret = __copy_from_user(&fpu->state.fxsave, buf_fx, state_size);
if (ret) {
ret = -EFAULT;
goto err_out;
goto out;
}
sanitize_restored_xstate(&fpu->state, envp, xfeatures, fx_only);
@ -397,7 +401,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
} else {
ret = __copy_from_user(&fpu->state.fsave, buf_fx, state_size);
if (ret)
goto err_out;
goto out;
fpregs_lock();
ret = copy_kernel_to_fregs_err(&fpu->state.fsave);
@ -408,7 +412,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
fpregs_deactivate(fpu);
fpregs_unlock();
err_out:
out:
if (ret)
fpu__clear(fpu);
return ret;