knownhosts: Add ssh_known_hosts_read_entries()

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>

src/knownhosts.c

@@ -142,6 +142,93 @@ void ssh_knownhosts_entry_free(struct ssh_knownhosts_entry *entry)
     SAFE_FREE(entry);
 }
 
+static int known_hosts_read_line(FILE *fp,
+                                 char *buf,
+                                 size_t buf_size,
+                                 size_t *buf_len,
+                                 size_t *lineno)
+{
+    while (fgets(buf, buf_size, fp) != NULL) {
+        size_t len;
+        if (buf[0] == '\0') {
+            continue;
+        }
+
+        *lineno += 1;
+        len = strlen(buf);
+        if (buf_len != NULL) {
+            *buf_len = len;
+        }
+        if (buf[len - 1] == '\n' || feof(fp)) {
+            return 0;
+        } else {
+            errno = E2BIG;
+            return -1;
+        }
+    }
+
+    return -1;
+}
+
+static int ssh_known_hosts_read_entries(const char *match,
+                                        const char *filename,
+                                        struct ssh_list **entries)
+{
+    struct ssh_list *entry_list;
+    char line[8192];
+    size_t lineno = 0;
+    size_t len = 0;
+    FILE *fp;
+    int rc;
+
+    fp = fopen(filename, "r");
+    if (fp == NULL) {
+        return SSH_ERROR;
+    }
+
+    entry_list = ssh_list_new();
+    if (entry_list == NULL) {
+        return SSH_ERROR;
+    }
+
+    for (rc = known_hosts_read_line(fp, line, sizeof(line), &len, &lineno);
+         rc == 0;
+         rc = known_hosts_read_line(fp, line, sizeof(line), &len, &lineno)) {
+        struct ssh_knownhosts_entry *entry = NULL;
+        char *p;
+
+        if (line[len] != '\n') {
+            len = strcspn(line, "\n");
+        }
+        line[len] = '\0';
+
+        /* Skip leading spaces */
+        for (p = line; isspace((int)p[0]); p++);
+
+        /* Skip comments and empty lines */
+        if (p[0] == '\0' || p[0] == '#') {
+            continue;
+        }
+
+        rc = ssh_known_hosts_parse_line(match,
+                                        line,
+                                        &entry);
+        if (rc == SSH_AGAIN) {
+            continue;
+        } else if (rc != SSH_OK) {
+            goto error;
+        }
+        ssh_list_append(entry_list, entry);
+    }
+
+    *entries = entry_list;
+
+    return SSH_OK;
+error:
+    ssh_list_free(entry_list);
+    return SSH_ERROR;
+}
+
 /**
  * @brief Parse a line from a known_hosts entry into a structure
  *

tests/unittests/torture_knownhosts_parsing.c

@@ -199,6 +199,33 @@ static void torture_knownhosts_parse_line_hashed_ed25519(void **state) {
     SSH_KNOWNHOSTS_ENTRY_FREE(entry);
 }
 
+static void torture_knownhosts_read_file(void **state)
+{
+    const char *knownhosts_file = *state;
+    struct ssh_list *entry_list = NULL;
+    struct ssh_iterator *it = NULL;
+    int rc;
+
+    rc = ssh_known_hosts_read_entries("localhost",
+                                      knownhosts_file,
+                                      &entry_list);
+    assert_int_equal(rc, SSH_OK);
+    assert_non_null(entry_list);
+    it = ssh_list_get_iterator(entry_list);
+    assert_non_null(it);
+    for (;it != NULL; it = it->next) {
+        struct ssh_knownhosts_entry *entry = NULL;
+        enum ssh_keytypes_e type;
+
+        entry = ssh_iterator_value(struct ssh_knownhosts_entry *, it);
+        assert_non_null(entry);
+
+        assert_string_equal(entry->hostname, "localhost");
+        type = ssh_key_type(entry->publickey);
+        assert_int_equal(type, SSH_KEYTYPE_ED25519);
+    }
+}
+
 int torture_run_tests(void) {
     int rc;
     struct CMUnitTest tests[] = {
@@ -208,6 +235,9 @@ int torture_run_tests(void) {
         cmocka_unit_test(torture_knownhosts_parse_line_port_ed25519),
         cmocka_unit_test(torture_knownhosts_parse_line_pattern_ed25519),
         cmocka_unit_test(torture_knownhosts_parse_line_hashed_ed25519),
+        cmocka_unit_test_setup_teardown(torture_knownhosts_read_file,
+                                        setup_knownhosts_file,
+                                        teardown_knownhosts_file),
     };
 
     ssh_init();