Messages in this thread Patch in this message | | | From | Masami Hiramatsu <> | Subject | [PATCH] kprobes: Limit max data_size of the kretprobe instances | Date | Wed, 1 Dec 2021 23:45:50 +0900 |
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The kretprobe::data_size is unsigned (size_t) but it is used as 'data_size + sizeof(struct kretprobe_instance)'. Thus, it can be smaller than sizeof(struct kretprobe_instance) while allocating memory for the kretprobe_instance.
To avoid this issue, introduce a max limitation of the kretprobe::data_size. 4KB per instance should be OK.
Reported-by: zhangyue <zhangyue1@kylinos.cn> Fixes: f47cd9b553aa ("kprobes: kretprobe user entry-handler") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> --- include/linux/kprobes.h | 2 ++ kernel/kprobes.c | 3 +++ 2 files changed, 5 insertions(+)
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index e974caf39d3e..8c8f7a4d93af 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -153,6 +153,8 @@ struct kretprobe { struct kretprobe_holder *rph; }; +#define KRETPROBE_MAX_DATA_SIZE 4096 + struct kretprobe_instance { union { struct freelist_node freelist; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index e9db0c810554..21eccc961bba 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -2086,6 +2086,9 @@ int register_kretprobe(struct kretprobe *rp) } } + if (rp->data_size > KRETPROBE_MAX_DATA_SIZE) + return -E2BIG; + rp->kp.pre_handler = pre_handler_kretprobe; rp->kp.post_handler = NULL;
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