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rtnl: message - verify that we read the pending message size from the kernel

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Reuse the auth-checking for both the peek and the real read.
This commit is contained in:
Tom Gundersen 2014-05-10 19:55:00 +02:00
parent 127dc4ea94
commit 26349add97
1 changed files with 50 additions and 39 deletions
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89
src/libsystemd/sd-rtnl/rtnl-message.c
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@ -1098,61 +1098,28 @@ int socket_write_message(sd_rtnl *nl, sd_rtnl_message *m) {
return k;
}
/* On success, the number of bytes received is returned and *ret points to the received message
* which has a valid header and the correct size.
* If nothing useful was received 0 is returned.
* On failure, a negative error code is returned.
*/
int socket_read_message(sd_rtnl *rtnl) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *first = NULL;
static int socket_recv_message(int fd, struct iovec *iov, bool peek) {
uint8_t cred_buffer[CMSG_SPACE(sizeof(struct ucred))];
struct iovec iov = {};
struct msghdr msg = {
.msg_iov = &iov,
.msg_iov = iov,
.msg_iovlen = 1,
.msg_control = cred_buffer,
.msg_controllen = sizeof(cred_buffer),
};
struct cmsghdr *cmsg;
bool auth = false, multi_part = false, done = false;
struct nlmsghdr *new_msg;
size_t len;
bool auth = false;
int r;
unsigned i = 0;
assert(rtnl);
assert(rtnl->rbuffer);
assert(rtnl->rbuffer_allocated >= sizeof(struct nlmsghdr));
assert(fd >= 0);
assert(iov);
/* read nothing, just get the pending message size */
r = recvmsg(rtnl->fd, &msg, MSG_PEEK | MSG_TRUNC);
r = recvmsg(fd, &msg, MSG_TRUNC | (peek ? MSG_PEEK : 0));
if (r < 0)
/* no data */
return (errno == EAGAIN) ? 0 : -errno;
else if (r == 0)
/* connection was closed by the kernel */
return -ECONNRESET;
else
len = (size_t)r;
/* make room for the pending message */
if (!greedy_realloc((void **)&rtnl->rbuffer,
&rtnl->rbuffer_allocated,
len, sizeof(uint8_t)))
return -ENOMEM;
iov.iov_base = rtnl->rbuffer;
iov.iov_len = rtnl->rbuffer_allocated;
r = recvmsg(rtnl->fd, &msg, MSG_TRUNC);
if (r < 0)
/* no data */
return (errno == EAGAIN) ? 0 : -errno;
else if (r == 0)
/* 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 &&
@ -1172,6 +1139,50 @@ int socket_read_message(sd_rtnl *rtnl) {
/* not from the kernel, ignore */
return 0;
return r;
}
/* On success, the number of bytes received is returned and *ret points to the received message
* which has a valid header and the correct size.
* If nothing useful was received 0 is returned.
* On failure, a negative error code is returned.
*/
int socket_read_message(sd_rtnl *rtnl) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *first = NULL;
struct iovec iov = {};
bool multi_part = false, done = false;
struct nlmsghdr *new_msg;
size_t len;
int r;
unsigned i = 0;
assert(rtnl);
assert(rtnl->rbuffer);
assert(rtnl->rbuffer_allocated >= sizeof(struct nlmsghdr));
/* read nothing, just get the pending message size */
r = socket_recv_message(rtnl->fd, &iov, true);
if (r <= 0)
return r;
else
len = (size_t)r;
/* make room for the pending message */
if (!greedy_realloc((void **)&rtnl->rbuffer,
&rtnl->rbuffer_allocated,
len, sizeof(uint8_t)))
return -ENOMEM;
iov.iov_base = rtnl->rbuffer;
iov.iov_len = rtnl->rbuffer_allocated;
/* read the pending message */
r = socket_recv_message(rtnl->fd, &iov, false);
if (r <= 0)
return r;
else
len = (size_t)r;
if (len > rtnl->rbuffer_allocated)
/* message did not fit in read buffer */
return -EIO;