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bpf: Limit the number of kprobes when attaching program to multiple kprobes 

[ Upstream commit d6d1e6c17c ]

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: 0dcac27254 ("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>
This commit is contained in:
Hou Tao 2023-12-15 18:07:05 +08:00 committed by Greg Kroah-Hartman
parent 5735054af3
commit 3d83b820bf
1 changed files with 3 additions and 0 deletions
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3
kernel/trace/bpf_trace.c
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@ -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);