This is a note to let you know that I've just added the patch titled
kprobes: Limit max data_size of the kretprobe instances
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kprobes-limit-max-data_size-of-the-kretprobe-instances.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6bbfa44116689469267f1a6e3d233b52114139d2 Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Date: Wed, 1 Dec 2021 23:45:50 +0900
Subject: kprobes: Limit max data_size of the kretprobe instances
From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
commit 6bbfa44116689469267f1a6e3d233b52114139d2 upstream.
The 'kprobe::data_size' is unsigned, thus it can not be negative. But if
user sets it enough big number (e.g. (size_t)-8), the result of 'data_size
+ sizeof(struct kretprobe_instance)' becomes smaller than sizeof(struct
kretprobe_instance) or zero. In result, the kretprobe_instance are
allocated without enough memory, and kretprobe accesses outside of
allocated memory.
To avoid this issue, introduce a max limitation of the
kretprobe::data_size. 4KB per instance should be OK.
Link: https://lkml.kernel.org/r/163836995040.432120.10322772773821182925.stgit@devnote2
Cc: stable@xxxxxxxxxxxxxxx
Fixes: f47cd9b553aa ("kprobes: kretprobe user entry-handler")
Reported-by: zhangyue <zhangyue1@xxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/kprobes.h | 2 ++
kernel/kprobes.c | 3 +++
2 files changed, 5 insertions(+)
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -193,6 +193,8 @@ struct kretprobe {
raw_spinlock_t lock;
};
+#define KRETPROBE_MAX_DATA_SIZE 4096
+
struct kretprobe_instance {
struct hlist_node hlist;
struct kretprobe *rp;
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2004,6 +2004,9 @@ int register_kretprobe(struct kretprobe
}
}
+ if (rp->data_size > KRETPROBE_MAX_DATA_SIZE)
+ return -E2BIG;
+
rp->kp.pre_handler = pre_handler_kretprobe;
rp->kp.post_handler = NULL;
rp->kp.fault_handler = NULL;
Patches currently in stable-queue which might be from mhiramat@xxxxxxxxxx are
queue-4.14/kprobes-limit-max-data_size-of-the-kretprobe-instances.patch
