Merge pull request #85 from keszybz/selinux-context

5 files changed, 31 insertions, 78 deletions

diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c
index b4ca177f76..1103903358 100644
--- a/src/libsystemd/sd-bus/bus-control.c
+++ b/src/libsystemd/sd-bus/bus-control.c
@@ -979,8 +979,10 @@ static int bus_get_owner_creds_dbus1(sd_bus *bus, uint64_t mask, sd_bus_creds **
         _cleanup_bus_creds_unref_ sd_bus_creds *c = NULL;
         pid_t pid = 0;
         int r;
+        bool do_label = bus->label && (mask & SD_BUS_CREDS_SELINUX_CONTEXT);
 
-        if (!bus->ucred_valid && isempty(bus->label))
+        /* Avoid allocating anything if we have no chance of returning useful data */
+        if (!bus->ucred_valid && !do_label)
                 return -ENODATA;
 
         c = bus_creds_new();
@@ -1004,7 +1006,7 @@ static int bus_get_owner_creds_dbus1(sd_bus *bus, uint64_t mask, sd_bus_creds **
                 }
         }
 
-        if (!isempty(bus->label) && (mask & SD_BUS_CREDS_SELINUX_CONTEXT)) {
+        if (do_label) {
                 c->label = strdup(bus->label);
                 if (!c->label)
                         return -ENOMEM;
diff --git a/src/libsystemd/sd-bus/bus-creds.c b/src/libsystemd/sd-bus/bus-creds.c
index 4d67619cf8..1c365b7fcd 100644
--- a/src/libsystemd/sd-bus/bus-creds.c
+++ b/src/libsystemd/sd-bus/bus-creds.c
@@ -773,11 +773,13 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
                 return 0;
 
         /* Try to retrieve PID from creds if it wasn't passed to us */
-        if (pid <= 0 && (c->mask & SD_BUS_CREDS_PID))
+        if (pid > 0) {
+                c->pid = pid;
+                c->mask |= SD_BUS_CREDS_PID;
+        } else if (c->mask & SD_BUS_CREDS_PID)
                 pid = c->pid;
-
-        /* Without pid we cannot do much... */
-        if (pid <= 0)
+        else
+                /* Without pid we cannot do much... */
                 return 0;
 
         /* Try to retrieve TID from creds if it wasn't passed to us */
@@ -789,9 +791,6 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         if (missing == 0)
                 return 0;
 
-        c->pid = pid;
-        c->mask |= SD_BUS_CREDS_PID;
-
         if (tid > 0) {
                 c->tid = tid;
                 c->mask |= SD_BUS_CREDS_TID;
diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h
index 1351938c80..2ee0eabc02 100644
--- a/src/libsystemd/sd-bus/bus-internal.h
+++ b/src/libsystemd/sd-bus/bus-internal.h
@@ -261,7 +261,7 @@ struct sd_bus {
         usec_t auth_timeout;
 
         struct ucred ucred;
-        char label[NAME_MAX];
+        char *label;
 
         uint64_t creds_mask;
 
diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
index 5209db8c4d..9f3756f0c2 100644
--- a/src/libsystemd/sd-bus/bus-socket.c
+++ b/src/libsystemd/sd-bus/bus-socket.c
@@ -500,9 +500,7 @@ static int bus_socket_read_auth(sd_bus *b) {
         void *p;
         union {
                 struct cmsghdr cmsghdr;
-                uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
-                            CMSG_SPACE(sizeof(struct ucred)) +
-                            CMSG_SPACE(NAME_MAX)]; /*selinux label */
+                uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)];
         } control;
         struct cmsghdr *cmsg;
         bool handle_cmsg = false;
@@ -554,8 +552,8 @@ static int bus_socket_read_auth(sd_bus *b) {
 
         b->rbuffer_size += k;
 
-        if (handle_cmsg) {
-                for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+        if (handle_cmsg)
+                for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg))
                         if (cmsg->cmsg_level == SOL_SOCKET &&
                             cmsg->cmsg_type == SCM_RIGHTS) {
                                 int j;
@@ -566,31 +564,9 @@ static int bus_socket_read_auth(sd_bus *b) {
                                 j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
                                 close_many((int*) CMSG_DATA(cmsg), j);
                                 return -EIO;
-
-                        } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                                   cmsg->cmsg_type == SCM_CREDENTIALS &&
-                                   cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
-
-                                /* Ignore bogus data, which we might
-                                 * get on socketpair() sockets */
-                                if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) {
-                                        memcpy(&b->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
-                                        b->ucred_valid = true;
-                                }
-
-                        } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                                   cmsg->cmsg_type == SCM_SECURITY) {
-
-                                size_t l;
-
-                                l = cmsg->cmsg_len - CMSG_LEN(0);
-                                if (l > 0) {
-                                        memcpy(&b->label, CMSG_DATA(cmsg), l);
-                                        b->label[l] = 0;
-                                }
-                        }
-                }
-        }
+                        } else
+                                log_debug("Got unexpected auxiliary data with level=%d and type=%d",
+                                          cmsg->cmsg_level, cmsg->cmsg_type);
 
         r = bus_socket_auth_verify(b);
         if (r != 0)
@@ -600,18 +576,8 @@ static int bus_socket_read_auth(sd_bus *b) {
 }
 
 void bus_socket_setup(sd_bus *b) {
-        int enable;
-
         assert(b);
 
-        /* Enable SO_PASSCRED + SO_PASSEC. We try this on any
-         * socket, just in case. */
-        enable = !b->bus_client;
-        (void) setsockopt(b->input_fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable));
-
-        enable = !b->bus_client && (b->attach_flags & KDBUS_ATTACH_SECLABEL);
-        (void) setsockopt(b->input_fd, SOL_SOCKET, SO_PASSSEC, &enable, sizeof(enable));
-
         /* Increase the buffers to 8 MB */
         fd_inc_rcvbuf(b->input_fd, SNDBUF_SIZE);
         fd_inc_sndbuf(b->output_fd, SNDBUF_SIZE);
@@ -622,10 +588,17 @@ void bus_socket_setup(sd_bus *b) {
 }
 
 static void bus_get_peercred(sd_bus *b) {
+        int r;
+
         assert(b);
 
         /* Get the peer for socketpair() sockets */
         b->ucred_valid = getpeercred(b->input_fd, &b->ucred) >= 0;
+
+        /* Get the SELinux context of the peer */
+        r = getpeersec(b->input_fd, &b->label);
+        if (r < 0 && r != -EOPNOTSUPP)
+                log_debug_errno(r, "Failed to determine peer security context: %m");
 }
 
 static int bus_socket_start_auth_client(sd_bus *b) {
@@ -941,9 +914,7 @@ int bus_socket_read_message(sd_bus *bus) {
         void *b;
         union {
                 struct cmsghdr cmsghdr;
-                uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
-                            CMSG_SPACE(sizeof(struct ucred)) +
-                            CMSG_SPACE(NAME_MAX)]; /*selinux label */
+                uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)];
         } control;
         struct cmsghdr *cmsg;
         bool handle_cmsg = false;
@@ -990,8 +961,8 @@ int bus_socket_read_message(sd_bus *bus) {
 
         bus->rbuffer_size += k;
 
-        if (handle_cmsg) {
-                for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+        if (handle_cmsg)
+                for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg))
                         if (cmsg->cmsg_level == SOL_SOCKET &&
                             cmsg->cmsg_type == SCM_RIGHTS) {
                                 int n, *f;
@@ -1016,29 +987,9 @@ int bus_socket_read_message(sd_bus *bus) {
                                 memcpy(f + bus->n_fds, CMSG_DATA(cmsg), n * sizeof(int));
                                 bus->fds = f;
                                 bus->n_fds += n;
-                        } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                                   cmsg->cmsg_type == SCM_CREDENTIALS &&
-                                   cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
-
-                                /* Ignore bogus data, which we might
-                                 * get on socketpair() sockets */
-                                if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) {
-                                        memcpy(&bus->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
-                                        bus->ucred_valid = true;
-                                }
-
-                        } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                                   cmsg->cmsg_type == SCM_SECURITY) {
-
-                                size_t l;
-                                l = cmsg->cmsg_len - CMSG_LEN(0);
-                                if (l > 0) {
-                                        memcpy(&bus->label, CMSG_DATA(cmsg), l);
-                                        bus->label[l] = 0;
-                                }
-                        }
-                }
-        }
+                        } else
+                                log_debug("Got unexpected auxiliary data with level=%d and type=%d",
+                                          cmsg->cmsg_level, cmsg->cmsg_type);
 
         r = bus_socket_read_message_need(bus, &need);
         if (r < 0)
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index 598b1be8a6..2805b29839 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -131,6 +131,7 @@ static void bus_free(sd_bus *b) {
         if (b->kdbus_buffer)
                 munmap(b->kdbus_buffer, KDBUS_POOL_SIZE);
 
+        free(b->label);
         free(b->rbuffer);
         free(b->unique_name);
         free(b->auth_buffer);