From: Hou Tao <houtao1@xxxxxxxxxx>
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.
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link")
Reported-by: xingwei lee <xrivendell7@xxxxxxxxx>
Closes: https://lore.kernel.org/bpf/CABOYnLwwJY=yFAGie59LFsUsBAgHfroVqbzZ5edAXbFE3YiNVA@xxxxxxxxxxxxxx
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
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);
--
2.29.2
