unix_diag: Unix inode info NLA

Actually, the socket path if it's not anonymous doesn't give a clue to which file the socket is bound to. Even if the path is absolute, it can be unlinked and then new socket can be bound to it. With this NLA it's possible to check which file a particular socket is really bound to. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>

unix_diag: Unix inode info NLA
Actually, the socket path if it's not anonymous doesn't give a clue to which file the socket is bound to. Even if the path is absolute, it can be unlinked and then new socket can be bound to it. With this NLA it's possible to check which file a particular socket is really bound to. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Pavel Emelyanov · David S. Miller
1 parent f5248b48a6
Showing 2 changed files with 28 additions and 0 deletions Side-by-side Diff
include/linux/unix_diag.h
net/unix/diag.c
@@ -12,6 +12,7 @@
 };
  
 #define UDIAG_SHOW_NAME		0x00000001	/* show name (not path) */
+#define UDIAG_SHOW_VFS		0x00000002	/* show VFS inode info */
  
 struct unix_diag_msg {
 	__u8	udiag_family;
  
@@ -25,8 +26,14 @@
  
 enum {
 	UNIX_DIAG_NAME,
+	UNIX_DIAG_VFS,
  
 	UNIX_DIAG_MAX,
+};
+
+struct unix_diag_vfs {
+	__u32	udiag_vfs_ino;
+	__u32	udiag_vfs_dev;
 };
  
 #endif
@@ -26,6 +26,23 @@
 	return -EMSGSIZE;
 }
  
+static int sk_diag_dump_vfs(struct sock *sk, struct sk_buff *nlskb)
+{
+	struct dentry *dentry = unix_sk(sk)->dentry;
+	struct unix_diag_vfs *uv;
+
+	if (dentry) {
+		uv = UNIX_DIAG_PUT(nlskb, UNIX_DIAG_VFS, sizeof(*uv));
+		uv->udiag_vfs_ino = dentry->d_inode->i_ino;
+		uv->udiag_vfs_dev = dentry->d_sb->s_dev;
+	}
+
+	return 0;
+
+rtattr_failure:
+	return -EMSGSIZE;
+}
+
 static int sk_diag_fill(struct sock *sk, struct sk_buff *skb, struct unix_diag_req *req,
 		u32 pid, u32 seq, u32 flags, int sk_ino)
 {
@@ -46,6 +63,10 @@
  
 	if ((req->udiag_show & UDIAG_SHOW_NAME) &&
 			sk_diag_dump_name(sk, skb))
+		goto nlmsg_failure;
+
+	if ((req->udiag_show & UDIAG_SHOW_VFS) &&
+			sk_diag_dump_vfs(sk, skb))
 		goto nlmsg_failure;
  
 	nlh->nlmsg_len = skb_tail_pointer(skb) - b;
...	...	@@ -12,6 +12,7 @@
12	12	};
13	13
14	14	#define UDIAG_SHOW_NAME 0x00000001 /* show name (not path) */
	15	+#define UDIAG_SHOW_VFS 0x00000002 /* show VFS inode info */
15	16
16	17	struct unix_diag_msg {
17	18	__u8 udiag_family;
18	19
...	...	@@ -25,8 +26,14 @@
25	26
26	27	enum {
27	28	UNIX_DIAG_NAME,
	29	+ UNIX_DIAG_VFS,
28	30
29	31	UNIX_DIAG_MAX,
	32	+};
	33	+
	34	+struct unix_diag_vfs {
	35	+ __u32 udiag_vfs_ino;
	36	+ __u32 udiag_vfs_dev;
30	37	};
31	38
32	39	#endif
...	...	@@ -26,6 +26,23 @@
26	26	return -EMSGSIZE;
27	27	}
28	28
	29	+static int sk_diag_dump_vfs(struct sock sk, struct sk_buff nlskb)
	30	+{
	31	+ struct dentry *dentry = unix_sk(sk)->dentry;
	32	+ struct unix_diag_vfs *uv;
	33	+
	34	+ if (dentry) {
	35	+ uv = UNIX_DIAG_PUT(nlskb, UNIX_DIAG_VFS, sizeof(*uv));
	36	+ uv->udiag_vfs_ino = dentry->d_inode->i_ino;
	37	+ uv->udiag_vfs_dev = dentry->d_sb->s_dev;
	38	+ }
	39	+
	40	+ return 0;
	41	+
	42	+rtattr_failure:
	43	+ return -EMSGSIZE;
	44	+}
	45	+
29	46	static int sk_diag_fill(struct sock sk, struct sk_buff skb, struct unix_diag_req *req,
30	47	u32 pid, u32 seq, u32 flags, int sk_ino)
31	48	{
...	...	@@ -46,6 +63,10 @@
46	63
47	64	if ((req->udiag_show & UDIAG_SHOW_NAME) &&
48	65	sk_diag_dump_name(sk, skb))
	66	+ goto nlmsg_failure;
	67	+
	68	+ if ((req->udiag_show & UDIAG_SHOW_VFS) &&
	69	+ sk_diag_dump_vfs(sk, skb))
49	70	goto nlmsg_failure;
50	71
51	72	nlh->nlmsg_len = skb_tail_pointer(skb) - b;