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 5.4-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-5.4 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 | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -289,13 +289,17 @@ static int __fpu__restore_sig(void __use 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 __use 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 __use 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 __use 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 __use } 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 __use fpregs_deactivate(fpu); fpregs_unlock(); -err_out: +out: if (ret) fpu__clear(fpu); return ret; Patches currently in stable-queue which might be from tglx@xxxxxxxxxxxxx are queue-5.4/x86-process-check-pf_kthread-and-not-current-mm-for-kernel-threads.patch queue-5.4/x86-pkru-write-hardware-init-value-to-pkru-when-xstate-is-init.patch queue-5.4/x86-fpu-reset-state-for-all-signal-restore-failures.patch