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kprobes: Prohibit probing on CFI preamble symbol

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Do not allow to probe on "__cfi_" or "__pfx_" started symbol, because those
are used for CFI and not executed. Probing it will break the CFI.

Link: https://lore.kernel.org/all/168904024679.116016.18089228029322008512.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu (Google) 2023-07-11 10:50:47 +09:00
parent 02ab7234fc
commit de02f2ac5d
1 changed files with 13 additions and 1 deletions
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14
kernel/kprobes.c
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@ -1545,6 +1545,17 @@ static int check_ftrace_location(struct kprobe *p)
return 0;
}
static bool is_cfi_preamble_symbol(unsigned long addr)
{
char symbuf[KSYM_NAME_LEN];
if (lookup_symbol_name(addr, symbuf))
return false;
return str_has_prefix("__cfi_", symbuf) ||
str_has_prefix("__pfx_", symbuf);
}
static int check_kprobe_address_safe(struct kprobe *p,
struct module **probed_mod)
{
@ -1563,7 +1574,8 @@ static int check_kprobe_address_safe(struct kprobe *p,
within_kprobe_blacklist((unsigned long) p->addr) ||
jump_label_text_reserved(p->addr, p->addr) ||
static_call_text_reserved(p->addr, p->addr) ||
find_bug((unsigned long)p->addr)) {
find_bug((unsigned long)p->addr) ||
is_cfi_preamble_symbol((unsigned long)p->addr)) {
ret = -EINVAL;
goto out;
}