6.6-stable review patch. If anyone has any objections, please let me know.
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From: Hou Tao houtao1@huawei.com
[ 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@huawei.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Jiri Olsa jolsa@kernel.org Acked-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20231215100708.2265609-3-houtao@huaweicloud.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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);