summaryrefslogtreecommitdiffstats
path: root/arch/x86/lib
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/lib')
-rw-r--r--arch/x86/lib/insn-eval.c25
1 files changed, 22 insertions, 3 deletions
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 01e36bd..6bf819f 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -427,6 +427,14 @@ static int get_reg_offset(struct insn *insn, struct pt_regs *regs,
switch (type) {
case REG_TYPE_RM:
regno = X86_MODRM_RM(insn->modrm.value);
+
+ /*
+ * ModRM.mod == 0 and ModRM.rm == 5 means a 32-bit displacement
+ * follows the ModRM byte.
+ */
+ if (!X86_MODRM_MOD(insn->modrm.value) && regno == 5)
+ return -EDOM;
+
if (X86_REX_B(insn->rex_prefix.value))
regno += 8;
break;
@@ -770,10 +778,21 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs)
eff_addr = base + indx * (1 << X86_SIB_SCALE(sib));
} else {
addr_offset = get_reg_offset(insn, regs, REG_TYPE_RM);
- if (addr_offset < 0)
+ /*
+ * -EDOM means that we must ignore the address_offset.
+ * In such a case, in 64-bit mode the effective address
+ * relative to the RIP of the following instruction.
+ */
+ if (addr_offset == -EDOM) {
+ if (user_64bit_mode(regs))
+ eff_addr = (long)regs->ip + insn->length;
+ else
+ eff_addr = 0;
+ } else if (addr_offset < 0) {
goto out;
-
- eff_addr = regs_get_register(regs, addr_offset);
+ } else {
+ eff_addr = regs_get_register(regs, addr_offset);
+ }
}
eff_addr += insn->displacement.value;
OpenPOWER on IntegriCloud