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| author | Paolo Bonzini <pbonzini@redhat.com> | 2018-06-06 17:38:09 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-06-12 15:06:34 +0200 |
| commit | 3c9fa24ca7c9c47605672916491f79e8ccacb9e6 (patch) | |
| tree | 938330204174cabc88a26f00f72ce8652bcb49c0 /arch/x86/kvm/emulate.c | |
| parent | ce14e868a54edeb2e30cb7a7b104a2fc4b9d76ca (diff) | |
| download | linux-3c9fa24ca7c9c47605672916491f79e8ccacb9e6.tar.bz2 | |
kvm: x86: use correct privilege level for sgdt/sidt/fxsave/fxrstor access
The functions that were used in the emulation of fxrstor, fxsave, sgdt and
sidt were originally meant for task switching, and as such they did not
check privilege levels. This is very bad when the same functions are used
in the emulation of unprivileged instructions. This is CVE-2018-10853.
The obvious fix is to add a new argument to ops->read_std and ops->write_std,
which decides whether the access is a "system" access or should use the
processor's CPL.
Fixes: 129a72a0d3c8 ("KVM: x86: Introduce segmented_write_std", 2017-01-12)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/emulate.c')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index fcf54642b293..4c4f4263420c 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -815,14 +815,14 @@ static inline int jmp_rel(struct x86_emulate_ctxt *ctxt, int rel) static int linear_read_system(struct x86_emulate_ctxt *ctxt, ulong linear, void *data, unsigned size) { - return ctxt->ops->read_std(ctxt, linear, data, size, &ctxt->exception); + return ctxt->ops->read_std(ctxt, linear, data, size, &ctxt->exception, true); } static int linear_write_system(struct x86_emulate_ctxt *ctxt, ulong linear, void *data, unsigned int size) { - return ctxt->ops->write_std(ctxt, linear, data, size, &ctxt->exception); + return ctxt->ops->write_std(ctxt, linear, data, size, &ctxt->exception, true); } static int segmented_read_std(struct x86_emulate_ctxt *ctxt, @@ -836,7 +836,7 @@ static int segmented_read_std(struct x86_emulate_ctxt *ctxt, rc = linearize(ctxt, addr, size, false, &linear); if (rc != X86EMUL_CONTINUE) return rc; - return ctxt->ops->read_std(ctxt, linear, data, size, &ctxt->exception); + return ctxt->ops->read_std(ctxt, linear, data, size, &ctxt->exception, false); } static int segmented_write_std(struct x86_emulate_ctxt *ctxt, @@ -850,7 +850,7 @@ static int segmented_write_std(struct x86_emulate_ctxt *ctxt, rc = linearize(ctxt, addr, size, true, &linear); if (rc != X86EMUL_CONTINUE) return rc; - return ctxt->ops->write_std(ctxt, linear, data, size, &ctxt->exception); + return ctxt->ops->write_std(ctxt, linear, data, size, &ctxt->exception, false); } /* @@ -2928,12 +2928,12 @@ static bool emulator_io_port_access_allowed(struct x86_emulate_ctxt *ctxt, #ifdef CONFIG_X86_64 base |= ((u64)base3) << 32; #endif - r = ops->read_std(ctxt, base + 102, &io_bitmap_ptr, 2, NULL); + r = ops->read_std(ctxt, base + 102, &io_bitmap_ptr, 2, NULL, true); if (r != X86EMUL_CONTINUE) return false; if (io_bitmap_ptr + port/8 > desc_limit_scaled(&tr_seg)) return false; - r = ops->read_std(ctxt, base + io_bitmap_ptr + port/8, &perm, 2, NULL); + r = ops->read_std(ctxt, base + io_bitmap_ptr + port/8, &perm, 2, NULL, true); if (r != X86EMUL_CONTINUE) return false; if ((perm >> bit_idx) & mask) |