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Commit 47112e25 authored by Gerrit Renker's avatar Gerrit Renker Committed by David S. Miller
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udplite: Protection against coverage value wrap-around 



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.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6579e57b

Documentation/networking/udplite.txt

+1 −1
Original line number Original line Diff line number Diff line
@@ -148,7 +148,7 @@ 
        getsockopt(sockfd, SOL_SOCKET, SO_NO_CHECK, &value, ...);

        getsockopt(sockfd, SOL_SOCKET, SO_NO_CHECK, &value, ...);





  is meaningless (as in TCP). Packets with a zero checksum field are

  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

  4) Fragmentation

net/ipv4/udp.c

+4 −0
Original line number Original line Diff line number Diff line
@@ -1325,6 +1325,8 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, 
			return -ENOPROTOOPT;

			return -ENOPROTOOPT;

		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */

		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */

			val = 8;

			val = 8;

		else if (val > USHORT_MAX)

			val = USHORT_MAX;

		up->pcslen = val;

		up->pcslen = val;

		up->pcflag |= UDPLITE_SEND_CC;

		up->pcflag |= UDPLITE_SEND_CC;

		break;

		break;
@@ -1337,6 +1339,8 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname, 
			return -ENOPROTOOPT;

			return -ENOPROTOOPT;

		if (val != 0 && val < 8) /* Avoid silly minimal values.       */

		if (val != 0 && val < 8) /* Avoid silly minimal values.       */

			val = 8;

			val = 8;

		else if (val > USHORT_MAX)

			val = USHORT_MAX;

		up->pcrlen = val;

		up->pcrlen = val;

		up->pcflag |= UDPLITE_RECV_CC;

		up->pcflag |= UDPLITE_RECV_CC;

		break;

		break;