diff options
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index ace22916ade3..3cf24a218196 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -583,6 +583,7 @@ static struct uprobe_xol_ops branch_xol_ops = { static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) { u8 opc1 = OPCODE1(insn); + int i; /* has the side-effect of processing the entire instruction */ insn_get_length(insn); @@ -612,6 +613,16 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn) return -ENOSYS; } + /* + * 16-bit overrides such as CALLW (66 e8 nn nn) are not supported. + * Intel and AMD behavior differ in 64-bit mode: Intel ignores 66 prefix. + * No one uses these insns, reject any branch insns with such prefix. + */ + for (i = 0; i < insn->prefixes.nbytes; i++) { + if (insn->prefixes.bytes[i] == 0x66) + return -ENOTSUPP; + } + auprobe->branch.opc1 = opc1; auprobe->branch.ilen = insn->length; auprobe->branch.offs = insn->immediate.value; |