[PATCH 6.7 116/162] fprobe: Fix to allocate entry_data_size buffer with rethook instances

Greg Kroah-Hartman
2024-03-04T21:31:16Z

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

commit 6572786006fa96ad2c35bb31757f1f861298093b upstream.

Fix to allocate fprobe::entry_data_size buffer with rethook instances.
If fprobe doesn't allocate entry_data_size buffer for each rethook instance,
fprobe entry handler can cause a buffer overrun when storing entry data in
entry handler.

Link: https://lore.kernel.org/all/170920576727.107552.638161246679734051.stgit@devnote2/

Reported-by: Jiri Olsa <olsajiri@gmail.com>
Closes: https://lore.kernel.org/all/Zd9eBn2FTQzYyg7L@krava/
Fixes: 4bbd93455659 ("kprobes: kretprobe scalability improvement")
Cc: stable@vger.kernel.org
Tested-by: Jiri Olsa <olsajiri@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/trace/fprobe.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 6cd2a4e3afb8..9ff018245840 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -189,9 +189,6 @@ static int fprobe_init_rethook(struct fprobe *fp, int num)
{
int size;

- if (num <= 0)
- return -EINVAL;
-
if (!fp->exit_handler) {
fp->rethook = NULL;
return 0;
@@ -199,15 +196,16 @@ static int fprobe_init_rethook(struct fprobe *fp, int num)

/* Initialize rethook if needed */
if (fp->nr_maxactive)
- size = fp->nr_maxactive;
+ num = fp->nr_maxactive;
else
- size = num * num_possible_cpus() * 2;
- if (size <= 0)
+ num *= num_possible_cpus() * 2;
+ if (num <= 0)
return -EINVAL;

+ size = sizeof(struct fprobe_rethook_node) + fp->entry_data_size;
+
/* Initialize rethook */
- fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler,
- sizeof(struct fprobe_rethook_node), size);
+ fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler, size, num);
if (IS_ERR(fp->rethook))
return PTR_ERR(fp->rethook);

--
2.44.0