LSM: SafeSetID: add GID testing to selftest

GID security policies were added back in v5.10, update the selftest to
reflect this.

Signed-off-by: Micah Morton <mortonm@chromium.org>

diff --git a/tools/testing/selftests/safesetid/safesetid-test.c b/tools/testing/selftests/safesetid/safesetid-test.c
index c16977e4b9138a8e9da971b0565ef3c3527a0f04..a653c47a4ab5d8046038a43f4dabfa195768b113 100644 (file)
--- a/tools/testing/selftests/safesetid/safesetid-test.c
+++ b/tools/testing/selftests/safesetid/safesetid-test.c
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <errno.h>
 #include <pwd.h>
+#include <grp.h>
 #include <string.h>
 #include <syscall.h>
 #include <sys/capability.h>
@@ -120,6 +121,7 @@ static void ensure_user_exists(uid_t uid)
                snprintf(name_str, 10, "user %d", uid);
                p.pw_name=name_str;
                p.pw_uid=uid;
+               p.pw_gid=uid;
                p.pw_gecos="Test account";
                p.pw_dir="/dev/null";
                p.pw_shell="/bin/false";
@@ -131,6 +133,33 @@ static void ensure_user_exists(uid_t uid)
        }
 }
 
+static void ensure_group_exists(gid_t gid)
+{
+       struct group g;
+
+       FILE *fd;
+       char name_str[10];
+
+       if (getgrgid(gid) == NULL) {
+               memset(&g,0x00,sizeof(g));
+               fd=fopen("/etc/group","a");
+               if (fd == NULL)
+                       die("couldn't open group file\n");
+               if (fseek(fd, 0, SEEK_END))
+                       die("couldn't fseek group file\n");
+               snprintf(name_str, 10, "group %d", gid);
+               g.gr_name=name_str;
+               g.gr_gid=gid;
+               g.gr_passwd=NULL;
+               g.gr_mem=NULL;
+               int value = putgrent(&g,fd);
+               if (value != 0)
+                       die("putgrent failed\n");
+               if (fclose(fd))
+                       die("fclose failed\n");
+       }
+}
+
 static void ensure_securityfs_mounted(void)
 {
        int fd = open(add_uid_whitelist_policy_file, O_WRONLY);
@@ -175,6 +204,31 @@ static void write_uid_policies()
        }
 }
 
+static void write_gid_policies()
+{
+       static char *policy_str = UGID_POLICY_STRING;
+       ssize_t written;
+       int fd;
+
+       fd = open(add_gid_whitelist_policy_file, O_WRONLY);
+       if (fd < 0)
+               die("can't open add_gid_whitelist_policy file\n");
+       written = write(fd, policy_str, strlen(policy_str));
+       if (written != strlen(policy_str)) {
+               if (written >= 0) {
+                       die("short write to %s\n", add_gid_whitelist_policy_file);
+               } else {
+                       die("write to %s failed: %s\n",
+                               add_gid_whitelist_policy_file, strerror(errno));
+               }
+       }
+       if (close(fd) != 0) {
+               die("close of %s failed: %s\n",
+                       add_gid_whitelist_policy_file, strerror(errno));
+       }
+}
+
+
 static bool test_userns(bool expect_success)
 {
        uid_t uid;
@@ -265,6 +319,63 @@ static void test_setuid(uid_t child_uid, bool expect_success)
        die("should not reach here\n");
 }
 
+static void test_setgid(gid_t child_gid, bool expect_success)
+{
+       pid_t cpid, w;
+       int wstatus;
+
+       cpid = fork();
+       if (cpid == -1) {
+               die("fork\n");
+       }
+
+       if (cpid == 0) {            /* Code executed by child */
+               if (setgid(child_gid) < 0)
+                       exit(EXIT_FAILURE);
+               if (getgid() == child_gid)
+                       exit(EXIT_SUCCESS);
+               else
+                       exit(EXIT_FAILURE);
+       } else {                 /* Code executed by parent */
+               do {
+                       w = waitpid(cpid, &wstatus, WUNTRACED | WCONTINUED);
+                       if (w == -1) {
+                               die("waitpid\n");
+                       }
+
+                       if (WIFEXITED(wstatus)) {
+                               if (WEXITSTATUS(wstatus) == EXIT_SUCCESS) {
+                                       if (expect_success) {
+                                               return;
+                                       } else {
+                                               die("unexpected success\n");
+                                       }
+                               } else {
+                                       if (expect_success) {
+                                               die("unexpected failure\n");
+                                       } else {
+                                               return;
+                                       }
+                               }
+                       } else if (WIFSIGNALED(wstatus)) {
+                               if (WTERMSIG(wstatus) == 9) {
+                                       if (expect_success)
+                                               die("killed unexpectedly\n");
+                                       else
+                                               return;
+                               } else {
+                                       die("unexpected signal: %d\n", wstatus);
+                               }
+                       } else {
+                               die("unexpected status: %d\n", wstatus);
+                       }
+               } while (!WIFEXITED(wstatus) && !WIFSIGNALED(wstatus));
+       }
+
+       die("should not reach here\n");
+}
+
+
 static void ensure_users_exist(void)
 {
        ensure_user_exists(ROOT_UGID);
@@ -274,6 +385,15 @@ static void ensure_users_exist(void)
        ensure_user_exists(NO_POLICY_UGID);
 }
 
+static void ensure_groups_exist(void)
+{
+       ensure_group_exists(ROOT_UGID);
+       ensure_group_exists(RESTRICTED_PARENT_UGID);
+       ensure_group_exists(ALLOWED_CHILD1_UGID);
+       ensure_group_exists(ALLOWED_CHILD2_UGID);
+       ensure_group_exists(NO_POLICY_UGID);
+}
+
 static void drop_caps(bool setid_retained)
 {
        cap_value_t cap_values[] = {CAP_SETUID, CAP_SETGID};
@@ -290,9 +410,11 @@ static void drop_caps(bool setid_retained)
 
 int main(int argc, char **argv)
 {
+       ensure_groups_exist();
        ensure_users_exist();
        ensure_securityfs_mounted();
        write_uid_policies();
+       write_gid_policies();
 
        if (prctl(PR_SET_KEEPCAPS, 1L))
                die("Error with set keepcaps\n");
@@ -325,6 +447,12 @@ int main(int argc, char **argv)
        test_setuid(ALLOWED_CHILD2_UGID, true);
        test_setuid(NO_POLICY_UGID, false);
 
+       test_setgid(ROOT_UGID, false);
+       test_setgid(ALLOWED_CHILD1_UGID, true);
+       test_setgid(ALLOWED_CHILD2_UGID, true);
+       test_setgid(NO_POLICY_UGID, false);
+
+
        if (!test_userns(false)) {
                die("test_userns worked when it should fail\n");
        }
@@ -334,6 +462,9 @@ int main(int argc, char **argv)
        test_setuid(2, false);
        test_setuid(3, false);
        test_setuid(4, false);
+       test_setgid(2, false);
+       test_setgid(3, false);
+       test_setgid(4, false);
 
        // NOTE: this test doesn't clean up users that were created in
        // /etc/passwd or flush policies that were added to the LSM.