From: Masami Hiramatsu Date: Wed, 1 Dec 2021 14:45:50 +0000 (+0900) Subject: kprobes: Limit max data_size of the kretprobe instances X-Git-Tag: v4.19.220~31 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=89d3674af09c0d7603451fa59a27cc278a2d6ecf;p=users%2Fdwmw2%2Flinux.git kprobes: Limit max data_size of the kretprobe instances 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@vger.kernel.org Fixes: f47cd9b553aa ("kprobes: kretprobe user entry-handler") Reported-by: zhangyue Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index c28204e22b544..304e7a0f6b165 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -168,6 +168,8 @@ struct kretprobe { raw_spinlock_t lock; }; +#define KRETPROBE_MAX_DATA_SIZE 4096 + struct kretprobe_instance { struct hlist_node hlist; struct kretprobe *rp; diff --git a/kernel/kprobes.c b/kernel/kprobes.c index d4435fd6fc8bc..993b84cc1db5a 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1976,6 +1976,9 @@ 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; rp->kp.fault_handler = NULL;