From: Tao Chen <chen.dylane@linux.dev>
Date: Mon, 7 Apr 2025 03:57:52 +0000 (+0800)
Subject: bpf: Check link_create.flags parameter for multi_uprobe
X-Git-Tag: v6.16-rc1~131^2~74
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a76116f422c442ab691b4dcabb25613486d34360;p=thirdparty%2Flinux.git

bpf: Check link_create.flags parameter for multi_uprobe

The link_create.flags are currently not used for multi-uprobes, so return
-EINVAL if it is set, same as for other attach APIs.

We allow target_fd to have an arbitrary value for multi-uprobe, though,
as there are existing users (libbpf) relying on this.

Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link")
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250407035752.1108927-2-chen.dylane@linux.dev
---

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index ec19942321e6d..0f5906f43d7ca 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3379,6 +3379,9 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 	if (sizeof(u64) != sizeof(void *))
 		return -EOPNOTSUPP;
 
+	if (attr->link_create.flags)
+		return -EINVAL;
+
 	if (!is_uprobe_multi(prog))
 		return -EINVAL;