6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hou Tao <houtao1@xxxxxxxxxx>
[ Upstream commit d6d1e6c17cab2dcb7b8530c599f00e7de906d380 ]
An abnormally big cnt may also be assigned to kprobe_multi.cnt when
attaching multiple kprobes. 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 kprobes in
bpf_kprobe_multi_link_attach(). If the number of kprobes is greater than
MAX_KPROBE_MULTI_CNT, the attachment will fail and return -E2BIG.
Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20231215100708.2265609-3-houtao@xxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/trace/bpf_trace.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 39c4cef98b95..1d76f3b014ae 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -42,6 +42,7 @@
rcu_dereference_protected(p, lockdep_is_held(&bpf_event_mutex))
#define MAX_UPROBE_MULTI_CNT (1U << 20)
+#define MAX_KPROBE_MULTI_CNT (1U << 20)
#ifdef CONFIG_MODULES
struct bpf_trace_module {
@@ -2897,6 +2898,8 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
cnt = attr->link_create.kprobe_multi.cnt;
if (!cnt)
return -EINVAL;
+ if (cnt > MAX_KPROBE_MULTI_CNT)
+ return -E2BIG;
size = cnt * sizeof(*addrs);
addrs = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);
--
2.43.0
