From 8b2efe51ba85ca83460941672afac6fca4199df6 Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Fri, 15 Dec 2023 18:07:04 +0800 Subject: [PATCH] bpf: Limit the number of uprobes when attaching program to multiple uprobes An abnormally big cnt may be passed to link_create.uprobe_multi.cnt, and it will trigger the following warning in kvmalloc_node(): if (unlikely(size > INT_MAX)) { WARN_ON_ONCE(!(flags & __GFP_NOWARN)); return NULL; } Fix the warning by limiting the maximal number of uprobes in bpf_uprobe_multi_link_attach(). If the number of uprobes is greater than MAX_UPROBE_MULTI_CNT, the attachment will return -E2BIG. Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link") Reported-by: Xingwei Lee Signed-off-by: Hou Tao Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Acked-by: Andrii Nakryiko Closes: https://lore.kernel.org/bpf/CABOYnLwwJY=yFAGie59LFsUsBAgHfroVqbzZ5edAXbFE3YiNVA@mail.gmail.com Link: https://lore.kernel.org/bpf/20231215100708.2265609-2-houtao@huaweicloud.com --- kernel/trace/bpf_trace.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 774cf476a892..75c05aea9fd9 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -42,6 +42,8 @@ #define bpf_event_rcu_dereference(p) \ rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex)) +#define MAX_UPROBE_MULTI_CNT (1U << 20) + #ifdef CONFIG_MODULES struct bpf_trace_module { struct module *module; @@ -3344,6 +3346,8 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr if (!upath || !uoffsets || !cnt) return -EINVAL; + if (cnt > MAX_UPROBE_MULTI_CNT) + return -E2BIG; uref_ctr_offsets = u64_to_user_ptr(attr->link_create.uprobe_multi.ref_ctr_offsets); ucookies = u64_to_user_ptr(attr->link_create.uprobe_multi.cookies); -- 2.25.1