udplite: Protection against coverage value wrap-around

[ Upstream commit 47112e25da41d9059626033986dc3353e101f815 ]

This patch clamps the cscov setsockopt values to a maximum of 0xFFFF.

Setsockopt values greater than 0xffff can cause an unwanted
wrap-around.  Further, IPv6 jumbograms are not supported (RFC 3838,
3.5), so that values greater than 0xffff are not even useful.

Further changes: fixed a typo in the documentation.

[ Add USHORT_MAX from upstream to linux/kernel.h -DaveM ]

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/networking/udplite.txt b/Documentation/networking/udplite.txt
index 3870f280280b34e6f81cce2229b896357091f7c6..855d8da57a232bd12f765205c4ef047b51264006 100644 (file)
--- a/Documentation/networking/udplite.txt
+++ b/Documentation/networking/udplite.txt
@@ -148,7 +148,7 @@
         getsockopt(sockfd, SOL_SOCKET, SO_NO_CHECK, &value, ...);
 
   is meaningless (as in TCP). Packets with a zero checksum field are
-  illegal (cf. RFC 3828, sec. 3.1) will be silently discarded.
+  illegal (cf. RFC 3828, sec. 3.1) and will be silently discarded.
 
   4) Fragmentation
 

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 2df44e77327002938f08d345f34e5e773cc37363..689026472306e145e66566fb4fb65f0ebe9e185e 100644 (file)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -20,6 +20,7 @@
 extern const char linux_banner[];
 extern const char linux_proc_banner[];
 
+#define USHORT_MAX     ((u16)(~0U))
 #define INT_MAX                ((int)(~0U>>1))
 #define INT_MIN                (-INT_MAX - 1)
 #define UINT_MAX       (~0U)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 1704c1474ea1c622e4c9c4375beea692b12f8072..9703c870f1dfa00f88a4d0c6c24c7adfca9f0332 100644 (file)
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1325,6 +1325,8 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
                        return -ENOPROTOOPT;
                if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
                        val = 8;
+               else if (val > USHORT_MAX)
+                       val = USHORT_MAX;
                up->pcslen = val;
                up->pcflag |= UDPLITE_SEND_CC;
                break;
@@ -1337,6 +1339,8 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
                        return -ENOPROTOOPT;
                if (val != 0 && val < 8) /* Avoid silly minimal values.       */
                        val = 8;
+               else if (val > USHORT_MAX)
+                       val = USHORT_MAX;
                up->pcrlen = val;
                up->pcflag |= UDPLITE_RECV_CC;
                break;