This patch removes duplication in the AVC netlink code
by introducing helper functions.
Did some basic testing and confirmed that messages are
received and processed.
More patches to follow.
Signed-off-by: Eamon Walsh <ewalsh@xxxxxxxxxxxxx>
---
avc_internal.c | 289 +++++++++++++++++++++------------------------------------
1 file changed, 107 insertions(+), 182 deletions(-)
Index: libselinux/src/avc_internal.c
===================================================================
--- libselinux/src/avc_internal.c (revision 2662)
+++ libselinux/src/avc_internal.c (working copy)
@@ -89,221 +89,146 @@
close(fd);
}
-int avc_netlink_check_nb(void)
+static int avc_netlink_receive(char *buf, unsigned buflen)
{
int rc;
struct sockaddr_nl nladdr;
socklen_t nladdrlen = sizeof nladdr;
- char buf[1024];
- struct nlmsghdr *nlh;
+ struct nlmsghdr *nlh = (struct nlmsghdr *)buf;
- while (1) {
- rc = recvfrom(fd, buf, sizeof(buf), 0,
- (struct sockaddr *)&nladdr, &nladdrlen);
- if (rc < 0) {
- if (errno == EINTR)
- continue;
- if (errno != EAGAIN) {
- avc_log("%s: socket error during read: %d\n",
- avc_prefix, errno);
- } else {
- errno = 0;
- rc = 0;
- }
- goto out;
- }
+ rc = recvfrom(fd, buf, buflen, 0, (struct sockaddr *)&nladdr,
+ &nladdrlen);
+ if (rc < 0)
+ return rc;
- if (nladdrlen != sizeof nladdr) {
- avc_log
- ("%s: warning: netlink address truncated, len %d?\n",
- avc_prefix, nladdrlen);
- rc = -1;
- goto out;
- }
+ if (nladdrlen != sizeof nladdr) {
+ avc_log("%s: warning: netlink address truncated, len %d?\n",
+ avc_prefix, nladdrlen);
+ return -1;
+ }
- if (nladdr.nl_pid) {
- avc_log
- ("%s: warning: received spoofed netlink packet from: %d\n",
- avc_prefix, nladdr.nl_pid);
- continue;
- }
+ if (nladdr.nl_pid) {
+ avc_log("%s: warning: received spoofed netlink packet from: %d\n",
+ avc_prefix, nladdr.nl_pid);
+ return -1;
+ }
- if (rc == 0) {
- avc_log("%s: warning: received EOF on socket\n",
- avc_prefix);
- goto out;
- }
+ if (rc == 0) {
+ avc_log("%s: warning: received EOF on netlink socket\n",
+ avc_prefix);
+ errno = EBADFD;
+ return -1;
+ }
- nlh = (struct nlmsghdr *)buf;
+ if (nlh->nlmsg_flags & MSG_TRUNC || nlh->nlmsg_len > (unsigned)rc) {
+ avc_log("%s: warning: incomplete netlink message\n",
+ avc_prefix);
+ return -1;
+ }
- if (nlh->nlmsg_flags & MSG_TRUNC
- || nlh->nlmsg_len > (unsigned)rc) {
- avc_log("%s: warning: incomplete netlink message\n",
- avc_prefix);
- goto out;
- }
+ return 0;
+}
- rc = 0;
- switch (nlh->nlmsg_type) {
- case NLMSG_ERROR:{
- struct nlmsgerr *err = NLMSG_DATA(nlh);
+static int avc_netlink_process(char *buf)
+{
+ int rc;
+ struct nlmsghdr *nlh = (struct nlmsghdr *)buf;
- /* Netlink ack */
- if (err->error == 0)
- break;
+ switch (nlh->nlmsg_type) {
+ case NLMSG_ERROR:{
+ struct nlmsgerr *err = NLMSG_DATA(nlh);
- errno = -err->error;
- avc_log("%s: netlink error: %d\n", avc_prefix,
- errno);
- rc = -1;
- goto out;
- }
+ /* Netlink ack */
+ if (err->error == 0)
+ break;
- case SELNL_MSG_SETENFORCE:{
- struct selnl_msg_setenforce *msg =
- NLMSG_DATA(nlh);
- avc_log
- ("%s: received setenforce notice (enforcing=%d)\n",
- avc_prefix, msg->val);
- avc_enforcing = msg->val;
- if (avc_enforcing && (rc = avc_ss_reset(0)) < 0) {
- avc_log
- ("%s: cache reset returned %d (errno %d)\n",
- avc_prefix, rc, errno);
- goto out;
- }
- break;
- }
+ errno = -err->error;
+ avc_log("%s: netlink error: %d\n", avc_prefix, errno);
+ return -1;
+ }
- case SELNL_MSG_POLICYLOAD:{
- struct selnl_msg_policyload *msg =
- NLMSG_DATA(nlh);
- avc_log
- ("%s: received policyload notice (seqno=%d)\n",
- avc_prefix, msg->seqno);
- rc = avc_ss_reset(msg->seqno);
- if (rc < 0) {
- avc_log
- ("%s: cache reset returned %d (errno %d)\n",
- avc_prefix, rc, errno);
- goto out;
- }
- break;
- }
+ case SELNL_MSG_SETENFORCE:{
+ struct selnl_msg_setenforce *msg = NLMSG_DATA(nlh);
+ avc_log("%s: received setenforce notice (enforcing=%d)\n",
+ avc_prefix, msg->val);
+ avc_enforcing = msg->val;
+ if (avc_enforcing && (rc = avc_ss_reset(0)) < 0) {
+ avc_log("%s: cache reset returned %d (errno %d)\n",
+ avc_prefix, rc, errno);
+ return rc;
+ }
+ break;
+ }
- default:
- avc_log("%s: warning: unknown netlink message %d\n",
- avc_prefix, nlh->nlmsg_type);
+ case SELNL_MSG_POLICYLOAD:{
+ struct selnl_msg_policyload *msg = NLMSG_DATA(nlh);
+ avc_log("%s: received policyload notice (seqno=%d)\n",
+ avc_prefix, msg->seqno);
+ rc = avc_ss_reset(msg->seqno);
+ if (rc < 0) {
+ avc_log("%s: cache reset returned %d (errno %d)\n",
+ avc_prefix, rc, errno);
+ return rc;
}
+ break;
}
- out:
- return rc;
+
+ default:
+ avc_log("%s: warning: unknown netlink message %d\n",
+ avc_prefix, nlh->nlmsg_type);
+ }
+ return 0;
}
-/* run routine for the netlink listening thread */
-void avc_netlink_loop(void)
+int avc_netlink_check_nb(void)
{
- int ret;
- struct sockaddr_nl nladdr;
- socklen_t nladdrlen = sizeof nladdr;
+ int rc;
char buf[1024];
- struct nlmsghdr *nlh;
while (1) {
- ret =
- recvfrom(fd, buf, sizeof(buf), 0,
- (struct sockaddr *)&nladdr, &nladdrlen);
- if (ret < 0) {
- if (errno == EINTR)
+ errno = 0;
+ rc = avc_netlink_receive(buf, sizeof(buf));
+ if (rc < 0) {
+ if (errno == EWOULDBLOCK)
+ return 0;
+ if (errno == 0 || errno == EINTR)
continue;
- avc_log("%s: netlink thread: recvfrom: error %d\n",
- avc_prefix, errno);
- goto out;
+ else {
+ avc_log("%s: netlink recvfrom: error %d\n",
+ avc_prefix, errno);
+ return rc;
+ }
}
- if (nladdrlen != sizeof nladdr) {
- avc_log
- ("%s: warning: netlink address truncated, len %d?\n",
- avc_prefix, nladdrlen);
- ret = -1;
- goto out;
- }
+ (void)avc_netlink_process(buf);
+ }
+ return 0;
+}
- if (nladdr.nl_pid) {
- avc_log
- ("%s: warning: received spoofed netlink packet from: %d\n",
- avc_prefix, nladdr.nl_pid);
- continue;
- }
+/* run routine for the netlink listening thread */
+void avc_netlink_loop(void)
+{
+ int rc;
+ char buf[1024];
- if (ret == 0) {
- avc_log("%s: netlink thread: received EOF on socket\n",
- avc_prefix);
- goto out;
- }
-
- nlh = (struct nlmsghdr *)buf;
-
- if (nlh->nlmsg_flags & MSG_TRUNC
- || nlh->nlmsg_len > (unsigned)ret) {
- avc_log
- ("%s: netlink thread: incomplete netlink message\n",
- avc_prefix);
- goto out;
- }
-
- switch (nlh->nlmsg_type) {
- case NLMSG_ERROR:{
- struct nlmsgerr *err = NLMSG_DATA(nlh);
-
- /* Netlink ack */
- if (err->error == 0)
- break;
-
- avc_log("%s: netlink thread: msg: error %d\n",
- avc_prefix, -err->error);
- goto out;
- }
-
- case SELNL_MSG_SETENFORCE:{
- struct selnl_msg_setenforce *msg =
- NLMSG_DATA(nlh);
- avc_log
- ("%s: received setenforce notice (enforcing=%d)\n",
- avc_prefix, msg->val);
- avc_enforcing = msg->val;
- if (avc_enforcing && (ret = avc_ss_reset(0)) < 0) {
- avc_log
- ("%s: cache reset returned %d (errno %d)\n",
- avc_prefix, ret, errno);
- goto out;
- }
+ while (1) {
+ errno = 0;
+ rc = avc_netlink_receive(buf, sizeof(buf));
+ if (rc < 0) {
+ if (errno == 0 || errno == EINTR)
+ continue;
+ else {
+ avc_log("%s: netlink recvfrom: error %d\n",
+ avc_prefix, errno);
break;
}
-
- case SELNL_MSG_POLICYLOAD:{
- struct selnl_msg_policyload *msg =
- NLMSG_DATA(nlh);
- avc_log
- ("%s: received policyload notice (seqno=%d)\n",
- avc_prefix, msg->seqno);
- ret = avc_ss_reset(msg->seqno);
- if (ret < 0) {
- avc_log
- ("%s: netlink thread: cache reset returned %d (errno %d)\n",
- avc_prefix, ret, errno);
- goto out;
- }
- break;
- }
-
- default:
- avc_log
- ("%s: netlink thread: warning: unknown msg type %d\n",
- avc_prefix, nlh->nlmsg_type);
}
+
+ rc = avc_netlink_process(buf);
+ if (rc < 0)
+ break;
}
- out:
+
close(fd);
avc_netlink_trouble = 1;
avc_log("%s: netlink thread: errors encountered, terminating\n",
--
Eamon Walsh <ewalsh@xxxxxxxxxxxxx>
National Security Agency
--
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