4 files changed, 52 insertions, 14 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e55e4255a210..b63a592ad29d 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -419,6 +419,8 @@ static inline int bpf_map_attr_numa_node(const union bpf_attr *attr)
                 attr->numa_node : NUMA_NO_NODE;
 }
 
+struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type);
+
 #else /* !CONFIG_BPF_SYSCALL */
 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
 {
@@ -506,6 +508,12 @@ static inline int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu,
 {
         return 0;
 }
+
+static inline struct bpf_prog *bpf_prog_get_type_path(const char *name,
+                                enum bpf_prog_type type)
+{
+        return ERR_PTR(-EOPNOTSUPP);
+}
 #endif /* CONFIG_BPF_SYSCALL */
 
 static inline struct bpf_prog *bpf_prog_get_type(u32 ufd,
@@ -514,6 +522,8 @@ static inline struct bpf_prog *bpf_prog_get_type(u32 ufd,
         return bpf_prog_get_type_dev(ufd, type, false);
 }
 
+bool bpf_prog_get_ok(struct bpf_prog *, enum bpf_prog_type *, bool);
+
 int bpf_prog_offload_compile(struct bpf_prog *prog);
 void bpf_prog_offload_destroy(struct bpf_prog *prog);
 
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index 01aaef1a77c5..5bb5e49ef4c3 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -368,7 +368,45 @@ out:
         putname(pname);
         return ret;
 }
-EXPORT_SYMBOL_GPL(bpf_obj_get_user);
+
+static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type type)
+{
+        struct bpf_prog *prog;
+        int ret = inode_permission(inode, MAY_READ | MAY_WRITE);
+        if (ret)
+                return ERR_PTR(ret);
+
+        if (inode->i_op == &bpf_map_iops)
+                return ERR_PTR(-EINVAL);
+        if (inode->i_op != &bpf_prog_iops)
+                return ERR_PTR(-EACCES);
+
+        prog = inode->i_private;
+
+        ret = security_bpf_prog(prog);
+        if (ret < 0)
+                return ERR_PTR(ret);
+
+        if (!bpf_prog_get_ok(prog, &type, false))
+                return ERR_PTR(-EINVAL);
+
+        return bpf_prog_inc(prog);
+}
+
+struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type)
+{
+        struct bpf_prog *prog;
+        struct path path;
+        int ret = kern_path(name, LOOKUP_FOLLOW, &path);
+        if (ret)
+                return ERR_PTR(ret);
+        prog = __get_prog_inode(d_backing_inode(path.dentry), type);
+        if (!IS_ERR(prog))
+                touch_atime(&path);
+        path_put(&path);
+        return prog;
+}
+EXPORT_SYMBOL(bpf_prog_get_type_path);
 
 static void bpf_evict_inode(struct inode *inode)
 {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 2c4cfeaa8d5e..5cb783fc8224 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1057,7 +1057,7 @@ struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog)
 }
 EXPORT_SYMBOL_GPL(bpf_prog_inc_not_zero);
 
-static bool bpf_prog_get_ok(struct bpf_prog *prog,
+bool bpf_prog_get_ok(struct bpf_prog *prog,
                             enum bpf_prog_type *attach_type, bool attach_drv)
 {
         /* not an attachment, just a refcount inc, always allow */
diff --git a/net/netfilter/xt_bpf.c b/net/netfilter/xt_bpf.c
index 041da0d9c06f..fa2ca0a13619 100644
--- a/net/netfilter/xt_bpf.c
+++ b/net/netfilter/xt_bpf.c
@@ -52,18 +52,8 @@ static int __bpf_mt_check_fd(int fd, struct bpf_prog **ret)
 
 static int __bpf_mt_check_path(const char *path, struct bpf_prog **ret)
 {
-        mm_segment_t oldfs = get_fs();
-        int retval, fd;
-
-        set_fs(KERNEL_DS);
-        fd = bpf_obj_get_user(path, 0);
-        set_fs(oldfs);
-        if (fd < 0)
-                return fd;
-
-        retval = __bpf_mt_check_fd(fd, ret);
-        sys_close(fd);
-        return retval;
+        *ret = bpf_prog_get_type_path(path, BPF_PROG_TYPE_SOCKET_FILTER);
+        return PTR_ERR_OR_ZERO(*ret);
 }
 
 static int bpf_mt_check(const struct xt_mtchk_param *par)