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Message-Id: <20230813160605.1080385-31-sashal@kernel.org>
Date: Sun, 13 Aug 2023 12:06:04 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: "Masami Hiramatsu (Google)" <mhiramat@...nel.org>,
Steven Rostedt <rostedt@...dmis.org>,
Sasha Levin <sashal@...nel.org>, naveen.n.rao@...ux.ibm.com,
anil.s.keshavamurthy@...el.com, davem@...emloft.net,
linux-trace-kernel@...r.kernel.org
Subject: [PATCH AUTOSEL 5.15 31/31] kprobes: Prohibit probing on CFI preamble symbol
From: "Masami Hiramatsu (Google)" <mhiramat@...nel.org>
[ Upstream commit de02f2ac5d8cfb311f44f2bf144cc20002f1fbbd ]
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@...nel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@...dmis.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
kernel/kprobes.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 7e9fa1b7ff671..6cf561322bbe6 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1545,6 +1545,17 @@ int __weak arch_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;
}
--
2.40.1
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