[dpdk-dev] [PATCH v3 07/19] vhost: add number of fds to vhost-user messages and use it
Maxime Coquelin
maxime.coquelin at redhat.com
Mon Oct 8 14:56:16 CEST 2018
On 10/05/2018 11:56 AM, Ilya Maximets wrote:
> On 04.10.2018 11:13, Maxime Coquelin wrote:
>> As soons as some anciliarry datai (fds) are received, it is copied
>> without checking its length.
>>
>> This patch adds adds the number of fds received to the message,
>> which is set in read_vhost_message().
>>
>> This is preliminary work to support sending fds to Qemu.
>>
>> Signed-off-by: Dr. David Alan Gilbert <dgilbert at redhat.com>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
>> ---
>> lib/librte_vhost/socket.c | 21 ++++++++++++++++-----
>> lib/librte_vhost/vhost_user.c | 2 +-
>> lib/librte_vhost/vhost_user.h | 4 +++-
>> 3 files changed, 20 insertions(+), 7 deletions(-)
>>
>> diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
>> index d63031747..c04d3d305 100644
>> --- a/lib/librte_vhost/socket.c
>> +++ b/lib/librte_vhost/socket.c
>> @@ -94,18 +94,23 @@ static struct vhost_user vhost_user = {
>> .mutex = PTHREAD_MUTEX_INITIALIZER,
>> };
>>
>> -/* return bytes# of read on success or negative val on failure. */
>> +/*
>> + * return bytes# of read on success or negative val on failure. Update fdnum
>> + * with number of fds read.
>> + */
>> int
>> -read_fd_message(int sockfd, char *buf, int buflen, int *fds, int fd_num)
>> +read_fd_message(int sockfd, char *buf, int buflen, int *fds, int max_fds,
>> + int *fd_num)
>> {
>> struct iovec iov;
>> struct msghdr msgh;
>> - size_t fdsize = fd_num * sizeof(int);
>> - char control[CMSG_SPACE(fdsize)];
>> + char control[CMSG_SPACE(max_fds * sizeof(int))];
>> struct cmsghdr *cmsg;
>> int got_fds = 0;
>> int ret;
>>
>> + *fd_num = 0;
>> +
>> memset(&msgh, 0, sizeof(msgh));
>> iov.iov_base = buf;
>> iov.iov_len = buflen;
>> @@ -131,13 +136,19 @@ read_fd_message(int sockfd, char *buf, int buflen, int *fds, int fd_num)
>> if ((cmsg->cmsg_level == SOL_SOCKET) &&
>> (cmsg->cmsg_type == SCM_RIGHTS)) {
>> got_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
>> + if (got_fds > max_fds) {
>> + RTE_LOG(ERR, VHOST_CONFIG,
>> + "Received msg contains more fds than supported\n");
>> + return -1;
>
> Looks like we'll leak all that file descriptors here.
> I think, we need to get and close the valid ones anyway.
Indeed. I fixed it as below in upcoming iteration:
if (got_fds > max_fds) {
RTE_LOG(ERR, VHOST_CONFIG,
"Received msg contains more fds than supported\n");
tmp_fds = (int *)CMSG_DATA(cmsg);
while (got_fds--)
close(tmp_fds[got_fds]);
return -1;
}
>> + }
>> + *fd_num = got_fds;
>> memcpy(fds, CMSG_DATA(cmsg), got_fds * sizeof(int));
>> break;
>> }
>> }
>>
>> /* Clear out unused file descriptors */
>> - while (got_fds < fd_num)
>> + while (got_fds < max_fds)
>> fds[got_fds++] = -1;
>>
>> return ret;
>> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
>> index b6eae8dc5..ad69a267e 100644
>> --- a/lib/librte_vhost/vhost_user.c
>> +++ b/lib/librte_vhost/vhost_user.c
>> @@ -1518,7 +1518,7 @@ read_vhost_message(int sockfd, struct VhostUserMsg *msg)
>> int ret;
>>
>> ret = read_fd_message(sockfd, (char *)msg, VHOST_USER_HDR_SIZE,
>> - msg->fds, VHOST_MEMORY_MAX_NREGIONS);
>> + msg->fds, VHOST_MEMORY_MAX_NREGIONS, &msg->fd_num);
>> if (ret <= 0)
>> return ret;
>>
>> diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
>> index 42166adf2..dd0262f8f 100644
>> --- a/lib/librte_vhost/vhost_user.h
>> +++ b/lib/librte_vhost/vhost_user.h
>> @@ -132,6 +132,7 @@ typedef struct VhostUserMsg {
>> VhostUserVringArea area;
>> } payload;
>> int fds[VHOST_MEMORY_MAX_NREGIONS];
>> + int fd_num;
>> } __attribute((packed)) VhostUserMsg;
>>
>> #define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
>> @@ -146,7 +147,8 @@ int vhost_user_iotlb_miss(struct virtio_net *dev, uint64_t iova, uint8_t perm);
>> int vhost_user_host_notifier_ctrl(int vid, bool enable);
>>
>> /* socket.c */
>> -int read_fd_message(int sockfd, char *buf, int buflen, int *fds, int fd_num);
>> +int read_fd_message(int sockfd, char *buf, int buflen, int *fds, int max_fds,
>> + int *fd_num);
>> int send_fd_message(int sockfd, char *buf, int buflen, int *fds, int fd_num);
>>
>> #endif
>>
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