Commit be364c8c authored Nov 27, 2012 by Tommi Rantala Committed by David S. Miller Nov 28, 2012

sctp: fix memory leak in sctp_datamsg_from_user() when copy from user space fails



Trinity (the syscall fuzzer) discovered a memory leak in SCTP,
reproducible e.g. with the sendto() syscall by passing invalid
user space pointer in the second argument:

 #include <string.h>
 #include <arpa/inet.h>
 #include <sys/socket.h>

 int main(void)
 {
         int fd;
         struct sockaddr_in sa;

         fd = socket(AF_INET, SOCK_STREAM, 132 /*IPPROTO_SCTP*/);
         if (fd < 0)
                 return 1;

         memset(&sa, 0, sizeof(sa));
         sa.sin_family = AF_INET;
         sa.sin_addr.s_addr = inet_addr("127.0.0.1");
         sa.sin_port = htons(11111);

         sendto(fd, NULL, 1, 0, (struct sockaddr *)&sa, sizeof(sa));

         return 0;
 }

As far as I can tell, the leak has been around since ~2003.

Signed-off-by: Tommi Rantala <tt.rantala@gmail.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent b49d3c1e

net/sctp/chunk.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -284,7 +284,7 @@ struct sctp_datamsg sctp_datamsg_from_user(struct sctp_association asoc,
		goto errout;
		err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
		if (err < 0)
		goto errout;
		goto errout_chunk_free;

		offset += len;

		@@ -324,7 +324,7 @@ struct sctp_datamsg sctp_datamsg_from_user(struct sctp_association asoc,
		__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
		- (__u8 *)chunk->skb->data);
		if (err < 0)
		goto errout;
		goto errout_chunk_free;

		sctp_datamsg_assign(msg, chunk);
		list_add_tail(&chunk->frag_list, &msg->chunks);
		@@ -332,6 +332,9 @@ struct sctp_datamsg sctp_datamsg_from_user(struct sctp_association asoc,

		return msg;

		errout_chunk_free:
		sctp_chunk_free(chunk);

		errout:
		list_for_each_safe(pos, temp, &msg->chunks) {
		list_del_init(pos);

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