39ea9baffd
This is a preparation for the removal of the ->initialized member in the fpu struct. __fpu__restore_sig() is deactivating the FPU via fpu__drop() and then setting manually ->initialized followed by fpu__restore(). The result is that it is possible to manipulate fpu->state and the state of registers won't be saved/restored on a context switch which would overwrite fpu->state: fpu__drop(fpu): ... fpu->initialized = 0; preempt_enable(); <--- context switch Don't access the fpu->state while the content is read from user space and examined/sanitized. Use a temporary kmalloc() buffer for the preparation of the FPU registers and once the state is considered okay, load it. Should something go wrong, return with an error and without altering the original FPU registers. The removal of fpu__initialize() is a nop because fpu->initialized is already set for the user task. [ bp: Massage a bit. ] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Dave Hansen <dave.hansen@intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: kvm ML <kvm@vger.kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190403164156.19645-2-bigeasy@linutronix.de |
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| .. | ||
| bugs.c | ||
| core.c | ||
| init.c | ||
| Makefile | ||
| regset.c | ||
| signal.c | ||
| xstate.c | ||