[PATCH 4.9 49/71] x86/fpu: Reset state for all signal restore failures
From: Sasha Levin <sashal@kernel.org>
Date: 2021-06-28 15:21:22
Also in:
lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Thomas Gleixner <redacted>
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 <redacted>
Signed-off-by: Borislav Petkov <redacted>
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>
---
arch/x86/kernel/fpu/signal.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 769831d9fd11..07b0ebd49576 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c@@ -276,15 +276,23 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) return 0; } - if (!access_ok(VERIFY_READ, buf, size)) + if (!access_ok(VERIFY_READ, buf, size)) { + fpu__clear(fpu); return -EACCES; + } fpu__activate_curr(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)) { + int ret = fpregs_soft_set(current, NULL, 0, + sizeof(struct user_i387_ia32_struct), + NULL, buf); + + if (ret) + fpu__clear(fpu); + + return ret != 0; + } if (use_xsave()) { struct _fpx_sw_bytes fx_sw_user;
--
2.30.2