s4:kdc: Simplify principal_comp_strcmp_int() to handle only equality

We only ever use the principal comparison functions to check equality.
Having these functions only handle equality simplifies their
implementation and makes them a bit easier to use.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15482

Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Thu Oct 26 02:26:02 UTC 2023 on atb-devel-224

diff --git a/source4/kdc/db-glue.c b/source4/kdc/db-glue.c
index 32ef4041083eef146950f467fc42acc912655b40..3b2757a9f4ec091f3dbf150a54597021f822c109 100644 (file)
--- a/source4/kdc/db-glue.c
+++ b/source4/kdc/db-glue.c
@@ -883,19 +883,19 @@ out:
        return ret;
 }
 
-static krb5_error_code principal_comp_strcmp_int(krb5_context context,
-                                                krb5_const_principal principal,
-                                                unsigned int component,
-                                                const char *string,
-                                                bool do_strcasecmp,
-                                                int *cmp)
+static krb5_error_code is_principal_component_equal_impl(krb5_context context,
+                                                        krb5_const_principal principal,
+                                                        unsigned int component,
+                                                        const char *string,
+                                                        bool do_strcasecmp,
+                                                        bool *eq)
 {
        const char *p;
 
 #if defined(HAVE_KRB5_PRINCIPAL_GET_COMP_STRING)
        if (component >= krb5_princ_size(context, principal)) {
-               /* A non‐existent component compares less than any string. */
-               *cmp = -1;
+               /* A non‐existent component compares equal to no string. */
+               *eq = false;
                return 0;
        }
        p = krb5_principal_get_comp_string(context, principal, component);
@@ -903,9 +903,9 @@ static krb5_error_code principal_comp_strcmp_int(krb5_context context,
                return ENOENT;
        }
        if (do_strcasecmp) {
-               *cmp = strcasecmp(p, string);
+               *eq = strcasecmp(p, string) == 0;
        } else {
-               *cmp = strcmp(p, string);
+               *eq = strcmp(p, string) == 0;
        }
        return 0;
 #else
@@ -918,8 +918,8 @@ static krb5_error_code principal_comp_strcmp_int(krb5_context context,
        }
 
        if (component >= krb5_princ_size(context, principal)) {
-               /* A non‐existent component compares less than any string. */
-               *cmp = -1;
+               /* A non‐existent component compares equal to no string. */
+               *eq = false;
                return 0;
        }
 
@@ -931,55 +931,46 @@ static krb5_error_code principal_comp_strcmp_int(krb5_context context,
        p = d.data;
 
        len = strlen(string);
-
-       /*
-        * We explicitly return -1 or 1. Subtracting of the two lengths might
-        * give the wrong result if the result overflows or loses data when
-        * narrowed to int.
-        */
-       if (d.length < len) {
-               *cmp = -1;
-               return 0;
-       } else if (d.length > len) {
-               *cmp = 1;
+       if (d.length != len) {
+               *eq = false;
                return 0;
        }
 
        if (do_strcasecmp) {
-               *cmp = strncasecmp(p, string, len);
+               *eq = strncasecmp(p, string, len) == 0;
        } else {
-               *cmp = memcmp(p, string, len);
+               *eq = memcmp(p, string, len) == 0;
        }
        return 0;
 #endif
 }
 
-static krb5_error_code principal_comp_strcasecmp(krb5_context context,
-                                                krb5_const_principal principal,
-                                                unsigned int component,
-                                                const char *string,
-                                                int *cmp)
+static krb5_error_code is_principal_component_equal_ignoring_case(krb5_context context,
+                                                                 krb5_const_principal principal,
+                                                                 unsigned int component,
+                                                                 const char *string,
+                                                                 bool *eq)
 {
-       return principal_comp_strcmp_int(context,
-                                        principal,
-                                        component,
-                                        string,
-                                        true /* do_strcasecmp */,
-                                        cmp);
+       return is_principal_component_equal_impl(context,
+                                                principal,
+                                                component,
+                                                string,
+                                                true /* do_strcasecmp */,
+                                                eq);
 }
 
-static krb5_error_code principal_comp_strcmp(krb5_context context,
-                                            krb5_const_principal principal,
-                                            unsigned int component,
-                                            const char *string,
-                                            int *cmp)
+static krb5_error_code is_principal_component_equal(krb5_context context,
+                                                   krb5_const_principal principal,
+                                                   unsigned int component,
+                                                   const char *string,
+                                                   bool *eq)
 {
-       return principal_comp_strcmp_int(context,
-                                        principal,
-                                        component,
-                                        string,
-                                        false /* do_strcasecmp */,
-                                        cmp);
+       return is_principal_component_equal_impl(context,
+                                                principal,
+                                                component,
+                                                string,
+                                                false /* do_strcasecmp */,
+                                                eq);
 }
 
 static krb5_error_code is_kadmin_changepw(krb5_context context,
@@ -987,29 +978,29 @@ static krb5_error_code is_kadmin_changepw(krb5_context context,
                                          bool *is_changepw)
 {
        krb5_error_code ret = 0;
-       int cmp = 0;
+       bool eq = false;
 
        if (krb5_princ_size(context, principal) != 2) {
                *is_changepw = false;
                return 0;
        }
 
-       ret = principal_comp_strcmp(context, principal, 0, "kadmin", &cmp);
+       ret = is_principal_component_equal(context, principal, 0, "kadmin", &eq);
        if (ret) {
                return ret;
        }
 
-       if (cmp != 0) {
+       if (!eq) {
                *is_changepw = false;
                return 0;
        }
 
-       ret = principal_comp_strcmp(context, principal, 1, "changepw", &cmp);
+       ret = is_principal_component_equal(context, principal, 1, "changepw", &eq);
        if (ret) {
                return ret;
        }
 
-       *is_changepw = cmp == 0;
+       *is_changepw = eq;
        return 0;
 }
 
@@ -2597,14 +2588,14 @@ static krb5_error_code samba_kdc_fetch_krbtgt(krb5_context context,
                        direction = INBOUND;
                        realm = realm_princ_comp;
                } else {
-                       int cmp = 0;
+                       bool eq = false;
 
-                       ret = principal_comp_strcasecmp(context, principal, 1, lpcfg_realm(lp_ctx), &cmp);
+                       ret = is_principal_component_equal_ignoring_case(context, principal, 1, lpcfg_realm(lp_ctx), &eq);
                        if (ret) {
                                goto out;
                        }
 
-                       if (cmp == 0) {
+                       if (eq) {
                                /* look for outbound trust */
                                direction = OUTBOUND;
                                realm = realm_from_princ;
@@ -2951,15 +2942,15 @@ static krb5_error_code samba_kdc_lookup_realm(krb5_context context,
        }
 
        if (flags & SDB_F_GET_SERVER) {
-               int cmp = 0;
+               bool is_krbtgt = false;
 
-               ret = principal_comp_strcmp(context, principal, 0, KRB5_TGS_NAME, &cmp);
+               ret = is_principal_component_equal(context, principal, 0, KRB5_TGS_NAME, &is_krbtgt);
                if (ret) {
                        TALLOC_FREE(frame);
                        return ret;
                }
 
-               if (cmp == 0) {
+               if (is_krbtgt) {
                        /*
                         * we need to search krbtgt/ locally
                         */