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 8b2efe51ba85ca83460941672afac6fca4199df6 ]
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 xrivendell7@gmail.com 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 Closes: https://lore.kernel.org/bpf/CABOYnLwwJY=yFAGie59LFsUsBAgHfroVqbzZ5edAXbFE3Yi... Link: https://lore.kernel.org/bpf/20231215100708.2265609-2-houtao@huaweicloud.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 868008f56fec..39c4cef98b95 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -41,6 +41,8 @@ #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; @@ -3198,6 +3200,8 @@ 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);