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-rw-r--r--Documentation/networking/dccp.txt4
-rw-r--r--include/linux/dccp.h1
-rw-r--r--net/dccp/ccid.c48
-rw-r--r--net/dccp/ccid.h5
-rw-r--r--net/dccp/feat.c4
-rw-r--r--net/dccp/proto.c2
6 files changed, 64 insertions, 0 deletions
diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt
index 39131a3c78f8..f0aeb20fa63b 100644
--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -57,6 +57,10 @@ can be set before calling bind().
DCCP_SOCKOPT_GET_CUR_MPS is read-only and retrieves the current maximum packet
size (application payload size) in bytes, see RFC 4340, section 14.
+DCCP_SOCKOPT_AVAILABLE_CCIDS is also read-only and returns the list of CCIDs
+supported by the endpoint (see include/linux/dccp.h for symbolic constants).
+The caller needs to provide a sufficiently large (> 2) array of type uint8_t.
+
DCCP_SOCKOPT_SERVER_TIMEWAIT enables the server (listening socket) to hold
timewait state when closing the connection (RFC 4340, 8.3). The usual case is
that the closing server sends a CloseReq, whereupon the client holds timewait
diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index 484b8a1fb023..d3ac1bde60b4 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -209,6 +209,7 @@ struct dccp_so_feat {
#define DCCP_SOCKOPT_SERVER_TIMEWAIT 6
#define DCCP_SOCKOPT_SEND_CSCOV 10
#define DCCP_SOCKOPT_RECV_CSCOV 11
+#define DCCP_SOCKOPT_AVAILABLE_CCIDS 12
#define DCCP_SOCKOPT_CCID_RX_INFO 128
#define DCCP_SOCKOPT_CCID_TX_INFO 192
diff --git a/net/dccp/ccid.c b/net/dccp/ccid.c
index 8fe931a3d7a1..647cb0614f84 100644
--- a/net/dccp/ccid.c
+++ b/net/dccp/ccid.c
@@ -13,6 +13,13 @@
#include "ccid.h"
+static u8 builtin_ccids[] = {
+ DCCPC_CCID2, /* CCID2 is supported by default */
+#if defined(CONFIG_IP_DCCP_CCID3) || defined(CONFIG_IP_DCCP_CCID3_MODULE)
+ DCCPC_CCID3,
+#endif
+};
+
static struct ccid_operations *ccids[CCID_MAX];
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
static atomic_t ccids_lockct = ATOMIC_INIT(0);
@@ -86,6 +93,47 @@ static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
}
}
+/* check that up to @array_len members in @ccid_array are supported */
+bool ccid_support_check(u8 const *ccid_array, u8 array_len)
+{
+ u8 i, j, found;
+
+ for (i = 0, found = 0; i < array_len; i++, found = 0) {
+ for (j = 0; !found && j < ARRAY_SIZE(builtin_ccids); j++)
+ found = (ccid_array[i] == builtin_ccids[j]);
+ if (!found)
+ return false;
+ }
+ return true;
+}
+
+/**
+ * ccid_get_builtin_ccids - Provide copy of `builtin' CCID array
+ * @ccid_array: pointer to copy into
+ * @array_len: value to return length into
+ * This function allocates memory - caller must see that it is freed after use.
+ */
+int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len)
+{
+ *ccid_array = kmemdup(builtin_ccids, sizeof(builtin_ccids), gfp_any());
+ if (*ccid_array == NULL)
+ return -ENOBUFS;
+ *array_len = ARRAY_SIZE(builtin_ccids);
+ return 0;
+}
+
+int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
+ char __user *optval, int __user *optlen)
+{
+ if (len < sizeof(builtin_ccids))
+ return -EINVAL;
+
+ if (put_user(sizeof(builtin_ccids), optlen) ||
+ copy_to_user(optval, builtin_ccids, sizeof(builtin_ccids)))
+ return -EFAULT;
+ return 0;
+}
+
int ccid_register(struct ccid_operations *ccid_ops)
{
int err = -ENOBUFS;
diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h
index fdeae7b57319..259f5469d7d0 100644
--- a/net/dccp/ccid.h
+++ b/net/dccp/ccid.h
@@ -103,6 +103,11 @@ static inline void *ccid_priv(const struct ccid *ccid)
return (void *)ccid->ccid_priv;
}
+extern bool ccid_support_check(u8 const *ccid_array, u8 array_len);
+extern int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len);
+extern int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
+ char __user *, int __user *);
+
extern struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx,
gfp_t gfp);
diff --git a/net/dccp/feat.c b/net/dccp/feat.c
index 192d494a3816..f79fb5e33f5e 100644
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
@@ -342,6 +342,10 @@ static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local,
!dccp_feat_sp_list_ok(feat, sp_val, sp_len))
return -EINVAL;
+ /* Avoid negotiating alien CCIDs by only advertising supported ones */
+ if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len))
+ return -EOPNOTSUPP;
+
if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len))
return -ENOMEM;
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index 01332fe7a99a..b4b10cbd8880 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -649,6 +649,8 @@ static int do_dccp_getsockopt(struct sock *sk, int level, int optname,
case DCCP_SOCKOPT_GET_CUR_MPS:
val = dp->dccps_mss_cache;
break;
+ case DCCP_SOCKOPT_AVAILABLE_CCIDS:
+ return ccid_getsockopt_builtin_ccids(sk, len, optval, optlen);
case DCCP_SOCKOPT_SERVER_TIMEWAIT:
val = dp->dccps_server_timewait;
break;