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selinux: rework label query APIs 

APIs that query and return something cannot silently fail, they must
either return something useful, or an error. Fix that.

Also, properly rollback socket unit fd creation when something goes
wrong with the security framework.
This commit is contained in:
Lennart Poettering 2014-10-23 18:58:18 +02:00
parent 376a298096
commit 7f416dae9b
2 changed files with 68 additions and 85 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
src/core/socket.c
View File

@ -1139,22 +1139,33 @@ static int socket_open_fds(Socket *s) {
continue;
if (p->type == SOCKET_SOCKET) {
if (!know_label && s->selinux_context_from_net) {
r = mac_selinux_get_our_label(&label);
if (r < 0)
return r;
know_label = true;
} else if (!know_label) {
r = socket_instantiate_service(s);
if (r < 0)
return r;
if (!know_label) {
/* Figure out label, if we don't it know
* yet. We do it once, for the first
* socket where we need this and
* remember it for the rest. */
if (UNIT_ISSET(s->service) &&
SERVICE(UNIT_DEREF(s->service))->exec_command[SERVICE_EXEC_START]) {
r = mac_selinux_get_create_label_from_exe(SERVICE(UNIT_DEREF(s->service))->exec_command[SERVICE_EXEC_START]->path, &label);
if (r < 0 && r != -EPERM)
return r;
if (s->selinux_context_from_net) {
/* Get it from the network label */
r = mac_selinux_get_our_label(&label);
if (r < 0 && r != EOPNOTSUPP)
goto rollback;
} else {
/* Get it from the executable we are about to start */
r = socket_instantiate_service(s);
if (r < 0)
goto rollback;
if (UNIT_ISSET(s->service) &&
SERVICE(UNIT_DEREF(s->service))->exec_command[SERVICE_EXEC_START]) {
r = mac_selinux_get_create_label_from_exe(SERVICE(UNIT_DEREF(s->service))->exec_command[SERVICE_EXEC_START]->path, &label);
if (r < 0 && r != -EPERM && r != EOPNOTSUPP)
goto rollback;
}
}
know_label = true;
@ -1219,6 +1230,7 @@ static int socket_open_fds(Socket *s) {
rollback:
socket_close_fds(s);
mac_selinux_free(label);
return r;
}

113
src/shared/selinux-util.c
View File

@ -166,34 +166,30 @@ void mac_selinux_finish(void) {
}
int mac_selinux_get_create_label_from_exe(const char *exe, char **label) {
int r = 0;
int r = -EOPNOTSUPP;
#ifdef HAVE_SELINUX
_cleanup_security_context_free_ security_context_t mycon = NULL, fcon = NULL;
security_class_t sclass;
if (!mac_selinux_use()) {
*label = NULL;
return 0;
}
assert(exe);
assert(label);
if (!mac_selinux_use())
return -EOPNOTSUPP;
r = getcon(&mycon);
if (r < 0)
goto fail;
return -errno;
r = getfilecon(exe, &fcon);
if (r < 0)
goto fail;
return -errno;
sclass = string_to_security_class("process");
r = security_compute_create(mycon, fcon, sclass, (security_context_t *) label);
if (r == 0)
log_debug("SELinux Socket context for %s will be set to %s", exe, *label);
fail:
if (r < 0 && security_getenforce() == 1)
r = -errno;
if (r < 0)
return -errno;
#endif
return r;
@ -202,14 +198,15 @@ fail:
int mac_selinux_get_our_label(char **label) {
int r = -EOPNOTSUPP;
assert(label);
#ifdef HAVE_SELINUX
char *l = NULL;
if (!mac_selinux_use())
return -EOPNOTSUPP;
r = getcon(&l);
r = getcon(label);
if (r < 0)
return r;
*label = l;
return -errno;
#endif
return r;
@ -219,91 +216,65 @@ int mac_selinux_get_child_mls_label(int socket_fd, const char *exe, char **label
int r = -EOPNOTSUPP;
#ifdef HAVE_SELINUX
_cleanup_security_context_free_ security_context_t mycon = NULL, peercon = NULL, fcon = NULL, ret = NULL;
_cleanup_security_context_free_ security_context_t mycon = NULL, peercon = NULL, fcon = NULL;
_cleanup_context_free_ context_t pcon = NULL, bcon = NULL;
security_class_t sclass;
const char *range = NULL;
assert(socket_fd >= 0);
assert(exe);
assert(label);
if (!mac_selinux_use())
return -EOPNOTSUPP;
r = getcon(&mycon);
if (r < 0) {
r = -EINVAL;
goto out;
}
if (r < 0)
return -errno;
r = getpeercon(socket_fd, &peercon);
if (r < 0) {
r = -EINVAL;
goto out;
}
if (r < 0)
return -errno;
r = getexeccon(&fcon);
if (r < 0) {
r = -EINVAL;
goto out;
}
if (r < 0)
return -errno;
if (!fcon) {
/* If there is no context set for next exec let's use context
of target executable */
r = getfilecon(exe, &fcon);
if (r < 0) {
r = -errno;
goto out;
}
if (r < 0)
return -errno;
}
bcon = context_new(mycon);
if (!bcon) {
r = -ENOMEM;
goto out;
}
if (!bcon)
return -ENOMEM;
pcon = context_new(peercon);
if (!pcon) {
r = -ENOMEM;
goto out;
}
if (!pcon)
return -ENOMEM;
range = context_range_get(pcon);
if (!range) {
r = -errno;
goto out;
}
if (!range)
return -errno;
r = context_range_set(bcon, range);
if (r) {
r = -errno;
goto out;
}
if (r)
return -errno;
freecon(mycon);
mycon = strdup(context_str(bcon));
if (!mycon) {
r = -errno;
goto out;
}
if (!mycon)
return -ENOMEM;
sclass = string_to_security_class("process");
r = security_compute_create(mycon, fcon, sclass, &ret);
if (r < 0) {
r = -EINVAL;
goto out;
}
*label = ret;
ret = NULL;
r = 0;
out:
if (r < 0 && security_getenforce() == 1)
return r;
r = security_compute_create(mycon, fcon, sclass, (security_context_t *) label);
if (r < 0)
return -errno;
#endif
return r;
}