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author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-20 09:09:58 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-20 09:09:58 -0700 |
commit | 8363e795eb79a74c857ba89e3b04668a33fe3344 (patch) | |
tree | edfdbfa3be22e945ce84260d2a48b7fb6cdac210 /arch/x86/kernel/fpu/signal.c | |
parent | b84a7c286cecf0604a5f8bd5dfcd5e1ca7233e15 (diff) | |
parent | 28e5e44aa3f4e0e0370864ed008fb5e2d85f4dc8 (diff) | |
download | linux-8363e795eb79a74c857ba89e3b04668a33fe3344.tar.gz linux-8363e795eb79a74c857ba89e3b04668a33fe3344.tar.bz2 linux-8363e795eb79a74c857ba89e3b04668a33fe3344.zip |
Merge tag 'x86_urgent_for_v5.13_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
"A first set of urgent fixes to the FPU/XSTATE handling mess^W code.
(There's a lot more in the pipe):
- Prevent corruption of the XSTATE buffer in signal handling by
validating what is being copied from userspace first.
- Invalidate other task's preserved FPU registers on XRSTOR failure
(#PF) because latter can still modify some of them.
- Restore the proper PKRU value in case userspace modified it
- Reset FPU state when signal restoring fails
Other:
- Map EFI boot services data memory as encrypted in a SEV guest so
that the guest can access it and actually boot properly
- Two SGX correctness fixes: proper resources freeing and a NUMA fix"
* tag 'x86_urgent_for_v5.13_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Avoid truncating memblocks for SGX memory
x86/sgx: Add missing xa_destroy() when virtual EPC is destroyed
x86/fpu: Reset state for all signal restore failures
x86/pkru: Write hardware init value to PKRU when xstate is init
x86/process: Check PF_KTHREAD and not current->mm for kernel threads
x86/fpu: Invalidate FPU state after a failed XRSTOR from a user buffer
x86/fpu: Prevent state corruption in __fpu__restore_sig()
x86/ioremap: Map EFI-reserved memory as encrypted for SEV
Diffstat (limited to 'arch/x86/kernel/fpu/signal.c')
-rw-r--r-- | arch/x86/kernel/fpu/signal.c | 54 |
1 files changed, 35 insertions, 19 deletions
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index a4ec65317a7f..ec3ae3054792 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -307,13 +307,17 @@ 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; @@ -369,6 +373,25 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) fpregs_unlock(); return 0; } + + /* + * The above did an FPU restore operation, restricted to + * the user portion of the registers, and failed, but the + * microcode might have modified the FPU registers + * nevertheless. + * + * If the FPU registers do not belong to current, then + * invalidate the FPU register state otherwise the task might + * preempt current and return to user space with corrupted + * FPU registers. + * + * In case current owns the FPU registers then no further + * action is required. The fixup below will handle it + * correctly. + */ + if (test_thread_flag(TIF_NEED_FPU_LOAD)) + __cpu_invalidate_fpregs_state(); + fpregs_unlock(); } else { /* @@ -377,7 +400,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) */ ret = __copy_from_user(&env, buf, sizeof(env)); if (ret) - goto err_out; + goto out; envp = &env; } @@ -405,16 +428,9 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) if (use_xsave() && !fx_only) { u64 init_bv = xfeatures_mask_user() & ~user_xfeatures; - if (using_compacted_format()) { - ret = copy_user_to_xstate(&fpu->state.xsave, buf_fx); - } else { - ret = __copy_from_user(&fpu->state.xsave, buf_fx, state_size); - - if (!ret && state_size > offsetof(struct xregs_state, header)) - ret = validate_user_xstate_header(&fpu->state.xsave.header); - } + ret = copy_user_to_xstate(&fpu->state.xsave, buf_fx); if (ret) - goto err_out; + goto out; sanitize_restored_user_xstate(&fpu->state, envp, user_xfeatures, fx_only); @@ -434,7 +450,7 @@ 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_user_xstate(&fpu->state, envp, user_xfeatures, @@ -452,7 +468,7 @@ 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); @@ -463,7 +479,7 @@ 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_user_states(fpu); return ret; |