38 lines
1.3 KiB
Diff
38 lines
1.3 KiB
Diff
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x86/emulate: check cpl for all privileged instructions
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Without this, it is possible for userspace to load its own IDT or GDT.
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This is XSA-105.
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Reported-by: Andrei LUTAS <vlutas@bitdefender.com>
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Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
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Reviewed-by: Jan Beulich <jbeulich@suse.com>
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Tested-by: Andrei LUTAS <vlutas@bitdefender.com>
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--- xen/arch/x86/x86_emulate/x86_emulate.c
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+++ xen/arch/x86/x86_emulate/x86_emulate.c
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@@ -3314,6 +3314,7 @@ x86_emulate(
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goto swint;
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case 0xf4: /* hlt */
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+ generate_exception_if(!mode_ring0(), EXC_GP, 0);
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ctxt->retire.flags.hlt = 1;
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break;
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@@ -3710,6 +3711,7 @@ x86_emulate(
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break;
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case 2: /* lgdt */
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case 3: /* lidt */
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+ generate_exception_if(!mode_ring0(), EXC_GP, 0);
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generate_exception_if(ea.type != OP_MEM, EXC_UD, -1);
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fail_if(ops->write_segment == NULL);
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memset(®, 0, sizeof(reg));
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@@ -3738,6 +3740,7 @@ x86_emulate(
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case 6: /* lmsw */
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fail_if(ops->read_cr == NULL);
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fail_if(ops->write_cr == NULL);
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+ generate_exception_if(!mode_ring0(), EXC_GP, 0);
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if ( (rc = ops->read_cr(0, &cr0, ctxt)) )
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goto done;
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if ( ea.type == OP_REG )
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