diff options
| -rw-r--r-- | arch/x86/kernel/kprobes/opt.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c index 041f0b50bc27..08eb23074f92 100644 --- a/arch/x86/kernel/kprobes/opt.c +++ b/arch/x86/kernel/kprobes/opt.c @@ -272,6 +272,19 @@ static int insn_is_indirect_jump(struct insn *insn) return ret; } +static bool is_padding_int3(unsigned long addr, unsigned long eaddr) +{ + unsigned char ops; + + for (; addr < eaddr; addr++) { + if (get_kernel_nofault(ops, (void *)addr) < 0 || + ops != INT3_INSN_OPCODE) + return false; + } + + return true; +} + /* Decode whole function to ensure any instructions don't jump into target */ static int can_optimize(unsigned long paddr) { @@ -310,9 +323,14 @@ static int can_optimize(unsigned long paddr) return 0; kernel_insn_init(&insn, (void *)recovered_insn, MAX_INSN_SIZE); insn_get_length(&insn); - /* Another subsystem puts a breakpoint */ + /* + * In the case of detecting unknown breakpoint, this could be + * a padding INT3 between functions. Let's check that all the + * rest of the bytes are also INT3. + */ if (insn.opcode.bytes[0] == INT3_INSN_OPCODE) - return 0; + return is_padding_int3(addr, paddr - offset + size) ? 1 : 0; + /* Recover address */ insn.kaddr = (void *)addr; insn.next_byte = (void *)(addr + insn.length); |