Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH 2/2] uprobes: x86: Prohibit probing on MOV SS instruction | Date | Wed, 9 May 2018 21:58:45 +0900 |
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Since MOV SS and POP SS instructions will delay the exceptions until the next instruction is executed, we should not do single-stepping on it by uprobes.
uprobe already rejects probing on POP SS (0x1f), but allows probing on MOV SS (0x8e and reg == 2). This checks the target instruction and if it is MOV SS or POP SS, returns -ENOTSUPP to reject probing.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- arch/x86/kernel/uprobes.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 85c7ef23d99f..c84bb5396958 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -299,6 +299,10 @@ static int uprobe_init_insn(struct arch_uprobe *auprobe, struct insn *insn, bool if (is_prefix_bad(insn)) return -ENOTSUPP; + /* We should not singlestep on the exception masking instructions */ + if (insn_masking_exception(insn)) + return -ENOTSUPP; + if (x86_64) good_insns = good_insns_64; else
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