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sd-rtnl: use SO_PASSCRED

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This unifies the socket handling with other sd-* libraries.
This commit is contained in:
Tom Gundersen 2014-04-11 00:04:39 +02:00
parent 5ba85788ab
commit bc078e7163
2 changed files with 40 additions and 14 deletions
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49
src/libsystemd/sd-rtnl/rtnl-message.c
View file

@ -1019,12 +1019,17 @@ int socket_write_message(sd_rtnl *nl, sd_rtnl_message *m) {
*/
int socket_read_message(sd_rtnl *rtnl) {
_cleanup_free_ void *buffer = NULL;
uint8_t cred_buffer[CMSG_SPACE(sizeof(struct ucred))];
struct iovec iov = {};
struct msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = cred_buffer,
.msg_controllen = sizeof(cred_buffer),
};
struct cmsghdr *cmsg;
bool auth = false;
struct nlmsghdr *new_msg;
union {
struct sockaddr sa;
struct sockaddr_nl nl;
} addr;
socklen_t addr_len = sizeof(addr);
size_t need, len;
int r, ret = 0;
@ -1038,19 +1043,37 @@ int socket_read_message(sd_rtnl *rtnl) {
if (!buffer)
return -ENOMEM;
r = recvfrom(rtnl->fd, buffer, need, 0, &addr.sa, &addr_len);
iov.iov_base = buffer;
iov.iov_len = need;
r = recvmsg(rtnl->fd, &msg, 0);
if (r < 0)
return (errno == EAGAIN) ? 0 : -errno; /* no data */
/* no data */
return (errno == EAGAIN) ? 0 : -errno;
else if (r == 0)
return -ECONNRESET; /* connection was closed by the kernel */
else if (addr_len != sizeof(addr.nl) ||
addr.nl.nl_family != AF_NETLINK)
return -EIO; /* not a netlink message */
else if (addr.nl.nl_pid != 0)
return 0; /* not from the kernel */
/* connection was closed by the kernel */
return -ECONNRESET;
else
len = (size_t)r;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_CREDENTIALS &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
struct ucred *ucred = (void *)CMSG_DATA(cmsg);
/* from the kernel */
if (ucred->uid == 0 && ucred->pid == 0) {
auth = true;
break;
}
}
}
if (!auth)
/* not from the kernel, ignore */
return 0;
for (new_msg = buffer; NLMSG_OK(new_msg, len); new_msg = NLMSG_NEXT(new_msg, len)) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL;
const NLType *nl_type;

5
src/libsystemd/sd-rtnl/sd-rtnl.c
View file

@ -72,7 +72,7 @@ static bool rtnl_pid_changed(sd_rtnl *rtnl) {
int sd_rtnl_open(sd_rtnl **ret, uint32_t groups) {
_cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL;
socklen_t addrlen;
int r;
int r, one = 1;
assert_return(ret, -EINVAL);
@ -84,6 +84,9 @@ int sd_rtnl_open(sd_rtnl **ret, uint32_t groups) {
if (rtnl->fd < 0)
return -errno;
if (setsockopt(rtnl->fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) < 0)
return -errno;
rtnl->sockaddr.nl.nl_groups = groups;
addrlen = sizeof(rtnl->sockaddr);