4 files changed, 36 insertions, 1 deletions

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index d7f4f50b1e58..8790b3962e4b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1642,6 +1642,7 @@ union bpf_attr {
 				__aligned_u64	cookies;
 				__u32		cnt;
 				__u32		flags;
+				__u32		pid;
 			} uprobe_multi;
 		};
 	} link_create;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ef17cd05262e..10666d17b9e3 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -4882,7 +4882,7 @@ err_put:
 	return err;
 }
 
-#define BPF_LINK_CREATE_LAST_FIELD link_create.uprobe_multi.flags
+#define BPF_LINK_CREATE_LAST_FIELD link_create.uprobe_multi.pid
 static int link_create(union bpf_attr *attr, bpfptr_t uattr)
 {
 	struct bpf_prog *prog;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 0d59cac30c7e..e45aebed62f5 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3003,6 +3003,7 @@ struct bpf_uprobe_multi_link {
 	struct bpf_link link;
 	u32 cnt;
 	struct bpf_uprobe *uprobes;
+	struct task_struct *task;
 };
 
 struct bpf_uprobe_multi_run_ctx {
@@ -3035,6 +3036,8 @@ static void bpf_uprobe_multi_link_dealloc(struct bpf_link *link)
 	struct bpf_uprobe_multi_link *umulti_link;
 
 	umulti_link = container_of(link, struct bpf_uprobe_multi_link, link);
+	if (umulti_link->task)
+		put_task_struct(umulti_link->task);
 	path_put(&umulti_link->path);
 	kvfree(umulti_link->uprobes);
 	kfree(umulti_link);
@@ -3059,6 +3062,9 @@ static int uprobe_prog_run(struct bpf_uprobe *uprobe,
 	struct bpf_run_ctx *old_run_ctx;
 	int err = 0;
 
+	if (link->task && current != link->task)
+		return 0;
+
 	if (sleepable)
 		rcu_read_lock_trace();
 	else
@@ -3079,6 +3085,16 @@ static int uprobe_prog_run(struct bpf_uprobe *uprobe,
 	return err;
 }
 
+static bool
+uprobe_multi_link_filter(struct uprobe_consumer *con, enum uprobe_filter_ctx ctx,
+			 struct mm_struct *mm)
+{
+	struct bpf_uprobe *uprobe;
+
+	uprobe = container_of(con, struct bpf_uprobe, consumer);
+	return uprobe->link->task->mm == mm;
+}
+
 static int
 uprobe_multi_link_handler(struct uprobe_consumer *con, struct pt_regs *regs)
 {
@@ -3112,12 +3128,14 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 	unsigned long *ref_ctr_offsets = NULL;
 	struct bpf_link_primer link_primer;
 	struct bpf_uprobe *uprobes = NULL;
+	struct task_struct *task = NULL;
 	unsigned long __user *uoffsets;
 	u64 __user *ucookies;
 	void __user *upath;
 	u32 flags, cnt, i;
 	struct path path;
 	char *name;
+	pid_t pid;
 	int err;
 
 	/* no support for 32bit archs yet */
@@ -3161,6 +3179,15 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 		goto error_path_put;
 	}
 
+	pid = attr->link_create.uprobe_multi.pid;
+	if (pid) {
+		rcu_read_lock();
+		task = get_pid_task(find_vpid(pid), PIDTYPE_PID);
+		rcu_read_unlock();
+		if (!task)
+			goto error_path_put;
+	}
+
 	err = -ENOMEM;
 
 	link = kzalloc(sizeof(*link), GFP_KERNEL);
@@ -3195,11 +3222,15 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 			uprobes[i].consumer.ret_handler = uprobe_multi_link_ret_handler;
 		else
 			uprobes[i].consumer.handler = uprobe_multi_link_handler;
+
+		if (pid)
+			uprobes[i].consumer.filter = uprobe_multi_link_filter;
 	}
 
 	link->cnt = cnt;
 	link->uprobes = uprobes;
 	link->path = path;
+	link->task = task;
 
 	bpf_link_init(&link->link, BPF_LINK_TYPE_UPROBE_MULTI,
 		      &bpf_uprobe_multi_link_lops, prog);
@@ -3226,6 +3257,8 @@ error_free:
 	kvfree(ref_ctr_offsets);
 	kvfree(uprobes);
 	kfree(link);
+	if (task)
+		put_task_struct(task);
 error_path_put:
 	path_put(&path);
 	return err;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index d7f4f50b1e58..8790b3962e4b 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1642,6 +1642,7 @@ union bpf_attr {
 				__aligned_u64	cookies;
 				__u32		cnt;
 				__u32		flags;
+				__u32		pid;
 			} uprobe_multi;
 		};
 	} link_create;