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| author | Paolo Bonzini <pbonzini@redhat.com> | 2014-05-15 18:09:29 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2014-05-22 17:47:17 +0200 |
| commit | 5045b468037dfe1c848827ce10e99d87f5669160 (patch) | |
| tree | a3562a257ed1889b7bf5d6dcd4ecb67edc79fd41 | |
| parent | fb5e336b977086557739791ed51955c5913dc773 (diff) | |
| download | linux-5045b468037dfe1c848827ce10e99d87f5669160.tar.bz2 | |
KVM: x86: check CS.DPL against RPL during task switch
Table 7-1 of the SDM mentions a check that the code segment's
DPL must match the selector's RPL. This was not done by KVM,
fix it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/emulate.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 47e716ef46b7..2fa7ab069817 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -1411,7 +1411,7 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt, /* Does not support long mode */ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, - u16 selector, int seg, u8 cpl) + u16 selector, int seg, u8 cpl, bool in_task_switch) { struct desc_struct seg_desc, old_desc; u8 dpl, rpl; @@ -1486,6 +1486,9 @@ static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt, goto exception; break; case VCPU_SREG_CS: + if (in_task_switch && rpl != dpl) + goto exception; + if (!(seg_desc.type & 8)) goto exception; @@ -1547,7 +1550,7 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt, u16 selector, int seg) { u8 cpl = ctxt->ops->cpl(ctxt); - return __load_segment_descriptor(ctxt, selector, seg, cpl); + return __load_segment_descriptor(ctxt, selector, seg, cpl, false); } static void write_register_operand(struct operand *op) @@ -2440,19 +2443,19 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt, * Now load segment descriptors. If fault happens at this stage * it is handled in a context of new task */ - ret = __load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR, cpl); + ret = __load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl); + ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl); + ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl); + ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl); + ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; @@ -2577,25 +2580,25 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt, * Now load segment descriptors. If fault happenes at this stage * it is handled in a context of new task */ - ret = __load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR, cpl); + ret = __load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl); + ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl); + ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl); + ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl); + ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS, cpl); + ret = __load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; - ret = __load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS, cpl); + ret = __load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS, cpl, true); if (ret != X86EMUL_CONTINUE) return ret; |