From: Thomas Gleixner tglx@linutronix.de
stable inclusion from linux-4.19.196 commit 55cfd22f9b5a051fa815d6987825e00aa15427af
--------------------------------
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 Conflicts: arch/x86/kernel/fpu/signal.c Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/x86/kernel/fpu/signal.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index f6a1d299627c5..3d9f4b7b4121c 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -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(buf, size)) - return -EACCES; + if (!access_ok(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)