2018-03-30 04:26:52

by Greg Thelen

Subject: [PATCH] RDMA/ucma: reject AF_IB ip multicast requests

syzbot discovered that ucma_join_ip_multicast() mishandles AF_IB request
addresses. If an RDMA_USER_CM_CMD_JOIN_IP_MCAST request has
cmd.addr.sa_family=AF_IB then ucma_join_ip_multicast() reads beyond the
end of its cmd.addr.

Reject non IP RDMA_USER_CM_CMD_JOIN_IP_MCAST requests.
RDMA_USER_CM_CMD_JOIN_MCAST is interface for AF_IB multicast.

And add a buffer length safety check.

Fixes: 5bc2b7b397b0 ("RDMA/ucma: Allow user space to specify AF_IB when joining multicast")
Signed-off-by: Greg Thelen <[email protected]>
---
drivers/infiniband/core/ucma.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index e5a1e7d81326..e410e03940ff 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -1423,11 +1423,19 @@ static ssize_t ucma_join_ip_multicast(struct ucma_file *file,
if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
return -EFAULT;

+ switch (cmd.addr.sin6_family) {
+ case AF_INET:
+ case AF_INET6:
+ break;
+ default:
+ return -EINVAL;
+ }
+
join_cmd.response = cmd.response;
join_cmd.uid = cmd.uid;
join_cmd.id = cmd.id;
join_cmd.addr_size = rdma_addr_size((struct sockaddr *) &cmd.addr);
- if (!join_cmd.addr_size)
+ if (!join_cmd.addr_size || join_cmd.addr_size > sizeof(cmd.addr))
return -EINVAL;

join_cmd.join_flags = RDMA_MC_JOIN_FLAG_FULLMEMBER;
--
2.17.0.rc1.321.gba9d0f2565-goog

2018-03-31 01:33:44

by Greg Thelen

Subject: Re: [PATCH] RDMA/ucma: reject AF_IB ip multicast requests

On Thu, Mar 29, 2018 at 9:24 PM, Greg Thelen <[email protected]> wrote:
> syzbot discovered that ucma_join_ip_multicast() mishandles AF_IB request
> addresses. If an RDMA_USER_CM_CMD_JOIN_IP_MCAST request has
> cmd.addr.sa_family=AF_IB then ucma_join_ip_multicast() reads beyond the
> end of its cmd.addr.
>
> Reject non IP RDMA_USER_CM_CMD_JOIN_IP_MCAST requests.
> RDMA_USER_CM_CMD_JOIN_MCAST is interface for AF_IB multicast.
>
> And add a buffer length safety check.
>
> Fixes: 5bc2b7b397b0 ("RDMA/ucma: Allow user space to specify AF_IB when joining multicast")
> Signed-off-by: Greg Thelen <[email protected]>
> ---
> drivers/infiniband/core/ucma.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)

My patch is no longer needed. linus/master recently picked up
84652aefb347 ("RDMA/ucma: Introduce safer rdma_addr_size() variants")
which fixes the same issue.

> diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
> index e5a1e7d81326..e410e03940ff 100644
> --- a/drivers/infiniband/core/ucma.c
> +++ b/drivers/infiniband/core/ucma.c
> @@ -1423,11 +1423,19 @@ static ssize_t ucma_join_ip_multicast(struct ucma_file *file,
> if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
> return -EFAULT;
>
> + switch (cmd.addr.sin6_family) {
> + case AF_INET:
> + case AF_INET6:
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> join_cmd.response = cmd.response;
> join_cmd.uid = cmd.uid;
> join_cmd.id = cmd.id;
> join_cmd.addr_size = rdma_addr_size((struct sockaddr *) &cmd.addr);
> - if (!join_cmd.addr_size)
> + if (!join_cmd.addr_size || join_cmd.addr_size > sizeof(cmd.addr))
> return -EINVAL;
>
> join_cmd.join_flags = RDMA_MC_JOIN_FLAG_FULLMEMBER;
> --
> 2.17.0.rc1.321.gba9d0f2565-goog
>