Standardize name/hostname checks

Changes:

* Use only `invalid_name` to check the name and hostname instead of
  ad-hoc checks
* Standardize empty/invalid error messages for name/hostname

Note: This makes the hostname validation less strict, though it still
forbids control characters and only numbers.

Relates to #5578 #5708.

See also commit b4ffaa207 ("merges; more on cleaning up esc chars",
2023-02-14).

2 files changed, 9 insertions, 31 deletions

diff --git a/src/firejail/main.c b/src/firejail/main.c
index 715123279..df1c81f3a 100644
--- a/src/firejail/main.c
+++ b/src/firejail/main.c
@@ -2187,7 +2187,7 @@ int main(int argc, char **argv, char **envp) {
                 else if (strncmp(argv[i], "--name=", 7) == 0) {
                         cfg.name = argv[i] + 7;
                         if (strlen(cfg.name) == 0) {
-                                fprintf(stderr, "Error: please provide a name for sandbox\n");
+                                fprintf(stderr, "Error: invalid sandbox name: cannot be empty\n");
                                 return 1;
                         }
                         if (invalid_name(cfg.name)) {
@@ -2197,24 +2197,11 @@ int main(int argc, char **argv, char **envp) {
                 }
                 else if (strncmp(argv[i], "--hostname=", 11) == 0) {
                         cfg.hostname = argv[i] + 11;
-                        size_t len = strlen(cfg.hostname);
-                        if (len == 0 || len > 253) {
-                                fprintf(stderr, "Error: please provide a valid hostname for sandbox, with maximum length of 253 ASCII characters\n");
+                        if (strlen(cfg.hostname) == 0) {
+                                fprintf(stderr, "Error: invalid hostname: cannot be empty\n");
                                 return 1;
                         }
-                        int invalid = invalid_name(cfg.hostname);
-                        char* hostname = cfg.hostname;
-                        while (*hostname && !invalid) {
-                                invalid = invalid || !(
-                                                (*hostname >= 'a' && *hostname <= 'z') ||
-                                                (*hostname >= 'A' && *hostname <= 'Z') ||
-                                                (*hostname >= '0' && *hostname <= '9') ||
-                                                (*hostname == '-' || *hostname == '.'));
-                                hostname++;
-                        }
-                        invalid = invalid || cfg.hostname[0] == '-'; // must not start with -
-                        invalid = invalid || cfg.hostname[len - 1] == '-'; // must not end with -
-                        if (invalid) {
+                        if (invalid_name(cfg.hostname)) {
                                 fprintf(stderr, "Error: invalid hostname\n");
                                 return 1;
                         }
@@ -2847,7 +2834,7 @@ int main(int argc, char **argv, char **envp) {
                         // set sandbox name and start normally
                         cfg.name = argv[i] + 16;
                         if (strlen(cfg.name) == 0) {
-                                fprintf(stderr, "Error: please provide a name for sandbox\n");
+                                fprintf(stderr, "Error: invalid sandbox name: cannot be empty\n");
                                 return 1;
                         }
                 }
diff --git a/src/firejail/profile.c b/src/firejail/profile.c
index 202bcf4da..139ce0580 100644
--- a/src/firejail/profile.c
+++ b/src/firejail/profile.c
@@ -326,22 +326,13 @@ int profile_check_line(char *ptr, int lineno, const char *fname) {
         }
         // sandbox name
         else if (strncmp(ptr, "name ", 5) == 0) {
-                int only_numbers = 1;
                 cfg.name = ptr + 5;
                 if (strlen(cfg.name) == 0) {
-                        fprintf(stderr, "Error: invalid sandbox name\n");
+                        fprintf(stderr, "Error: invalid sandbox name: cannot be empty\n");
                         exit(1);
                 }
-                const char *c = cfg.name;
-                while (*c) {
-                        if (!isdigit(*c)) {
-                                only_numbers = 0;
-                                break;
-                        }
-                        ++c;
-                }
-                if (only_numbers) {
-                        fprintf(stderr, "Error: invalid sandbox name: it only contains digits\n");
+                if (invalid_name(cfg.name)) {
+                        fprintf(stderr, "Error: invalid sandbox name\n");
                         exit(1);
                 }
                 return 0;
@@ -1647,7 +1638,7 @@ int profile_check_line(char *ptr, int lineno, const char *fname) {
                         // set sandbox name and start normally
                         cfg.name = ptr + 14;
                         if (strlen(cfg.name) == 0) {
-                                fprintf(stderr, "Error: invalid sandbox name\n");
+                                fprintf(stderr, "Error: invalid sandbox name: cannot be empty\n");
                                 exit(1);
                         }
                 }