| Date | Fri, 28 Dec 2012 20:06:04 +0100 | From | Ben Hutchings <> | Subject | [ 154/173] sctp: fix -ENOMEM result with invalid user space pointer in sendto() syscall |
| |
3.2-stable review patch. If anyone has any objections, please let me know.
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From: Tommi Rantala <tt.rantala@gmail.com>
[ Upstream commit 6e51fe7572590d8d86e93b547fab6693d305fd0d ]
Consider the following program, that sets the second argument to the sendto() syscall incorrectly:
#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; }
We get -ENOMEM:
$ strace -e sendto ./demo sendto(3, NULL, 1, 0, {sa_family=AF_INET, sin_port=htons(11111), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 ENOMEM (Cannot allocate memory)
Propagate the error code from sctp_user_addto_chunk(), so that we will tell user space what actually went wrong:
$ strace -e sendto ./demo sendto(3, NULL, 1, 0, {sa_family=AF_INET, sin_port=htons(11111), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EFAULT (Bad address)
Noticed while running Trinity (the syscall fuzzer).
Signed-off-by: Tommi Rantala <tt.rantala@gmail.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/sctp/chunk.c | 13 +++++++++---- net/sctp/socket.c | 4 ++-- 2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/net/sctp/chunk.c b/net/sctp/chunk.c index 9534bf9..0018b65 100644 --- a/net/sctp/chunk.c +++ b/net/sctp/chunk.c @@ -183,7 +183,7 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, msg = sctp_datamsg_new(GFP_KERNEL); if (!msg) - return NULL; + return ERR_PTR(-ENOMEM); /* Note: Calculate this outside of the loop, so that all fragments * have the same expiration. @@ -280,8 +280,11 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0); - if (!chunk) + if (!chunk) { + err = -ENOMEM; goto errout; + } + err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov); if (err < 0) goto errout_chunk_free; @@ -315,8 +318,10 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0); - if (!chunk) + if (!chunk) { + err = -ENOMEM; goto errout; + } err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov); @@ -342,7 +347,7 @@ errout: sctp_chunk_free(chunk); } sctp_datamsg_put(msg); - return NULL; + return ERR_PTR(err); } /* Check whether this message has expired. */ diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 8e49d76..fa8333b 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -1908,8 +1908,8 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk, /* Break the message into multiple chunks of maximum size. */ datamsg = sctp_datamsg_from_user(asoc, sinfo, msg, msg_len); - if (!datamsg) { - err = -ENOMEM; + if (IS_ERR(datamsg)) { + err = PTR_ERR(datamsg); goto out_free; }
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