This is a note to let you know that I've just added the patch titled x86/fpu: Reset state for all signal restore failures to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-fpu-reset-state-for-all-signal-restore-failures.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From efa165504943f2128d50f63de0c02faf6dcceb0d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Date: Wed, 9 Jun 2021 21:18:00 +0200 Subject: x86/fpu: Reset state for all signal restore failures From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/87mtryyhhz.ffs@xxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/fpu/signal.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -272,6 +272,7 @@ static int __fpu__restore_sig(void __use 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 __use 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 __use fpu__restore(fpu); local_bh_enable(); + /* Failure is already handled */ return err; } else { /* @@ -356,13 +364,14 @@ static int __fpu__restore_sig(void __use * 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) Patches currently in stable-queue which might be from tglx@xxxxxxxxxxxxx are queue-4.14/x86-fpu-reset-state-for-all-signal-restore-failures.patch