lkml.org 
[lkml]   [2022]   [Apr]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] x86/kprobes: Fix KRETPROBES when CONFIG_KRETPROBE_ON_RETHOOK is set
[PATCH] x86/kprobes: Fix KRETPROBES when CONFIG_KRETPROBE_ON_RETHOOK is set

The recent kernel change "kprobes: Use rethook for kretprobe if possible",
introduced a potential NULL pointer dereference bug in the KRETPROBE
mechanism. The official Kprobes documentation defines that "Any or all
handlers can be NULL". Unfortunately, there is a missing return handler
verification to fulfill these requirements and can result in a NULL pointer
dereference bug.

This patch adds such verification in kretprobe_rethook_handler() function.

Fixes: 73f9b911faa7 ("kprobes: Use rethook for kretprobe if possible")
Signed-off-by: Adam Zabrocki <pi3@pi3.com.pl>
---
kernel/kprobes.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index dbe57df2e199..dd58c0be9ce2 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2126,7 +2126,7 @@ static void kretprobe_rethook_handler(struct rethook_node *rh, void *data,
struct kprobe_ctlblk *kcb;

/* The data must NOT be null. This means rethook data structure is broken. */
- if (WARN_ON_ONCE(!data))
+ if (WARN_ON_ONCE(!data) || !rp->handler)
return;

__this_cpu_write(current_kprobe, &rp->kp);
--
pi3 (pi3ki31ny) - pi3 (at) itsec pl
http://pi3.com.pl

\
 
 \ /
  Last update: 2022-04-15 20:11    [W:1.375 / U:0.964 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site