krb5 commit: Clean up gssapi_krb5 ccache name functions

https://github.com/krb5/krb5/commit/f573f7f8ee5269103a0492d6521a3242c5ffb63b
commit f573f7f8ee5269103a0492d6521a3242c5ffb63b
Author: Robbie Harwood <[email protected]>
Date:   Wed May 26 18:22:10 2021 -0400

    Clean up gssapi_krb5 ccache name functions
    
    Modernize kg_get_ccache_name() and kg_get_ccache_name().  Drop
    unnecessary use of const in kg_get_ccache_name() so that its return
    value can be properly freed.  Fixes some static analyzer false
    positives.

 src/lib/gssapi/krb5/gssapiP_krb5.h |    3 +-
 src/lib/gssapi/krb5/gssapi_krb5.c  |   47 +++++++++-----------------
 src/lib/gssapi/krb5/set_ccache.c   |   64 ++++++++++++++----------------------
 3 files changed, 42 insertions(+), 72 deletions(-)

diff --git a/src/lib/gssapi/krb5/gssapiP_krb5.h b/src/lib/gssapi/krb5/gssapiP_krb5.h
index d8553e7..a444653 100644
--- a/src/lib/gssapi/krb5/gssapiP_krb5.h
+++ b/src/lib/gssapi/krb5/gssapiP_krb5.h
@@ -380,8 +380,7 @@ OM_uint32 kg_sync_ccache_name (krb5_context context, OM_uint32 *minor_status);
 OM_uint32 kg_caller_provided_ccache_name (OM_uint32 *minor_status,
                                           int *out_caller_provided_name);
 
-OM_uint32 kg_get_ccache_name (OM_uint32 *minor_status,
-                              const char **out_name);
+OM_uint32 kg_get_ccache_name (OM_uint32 *minor_status, char **out_name);
 
 OM_uint32 kg_set_ccache_name (OM_uint32 *minor_status,
                               const char *name);
diff --git a/src/lib/gssapi/krb5/gssapi_krb5.c b/src/lib/gssapi/krb5/gssapi_krb5.c
index 46aa9b7..9915a8b 100644
--- a/src/lib/gssapi/krb5/gssapi_krb5.c
+++ b/src/lib/gssapi/krb5/gssapi_krb5.c
@@ -253,46 +253,31 @@ kg_caller_provided_ccache_name (OM_uint32 *minor_status,
 }
 
 OM_uint32
-kg_get_ccache_name (OM_uint32 *minor_status, const char **out_name)
+kg_get_ccache_name(OM_uint32 *minor_status, char **out_name)
 {
-    const char *name = NULL;
-    OM_uint32 err = 0;
     char *kg_ccache_name;
+    const char *def_name;
+    OM_uint32 err;
+    krb5_context context;
 
-    kg_ccache_name = k5_getspecific(K5_KEY_GSS_KRB5_CCACHE_NAME);
+    *out_name = NULL;
 
+    kg_ccache_name = k5_getspecific(K5_KEY_GSS_KRB5_CCACHE_NAME);
     if (kg_ccache_name != NULL) {
-        name = strdup(kg_ccache_name);
-        if (name == NULL)
-            err = ENOMEM;
+        *out_name = strdup(kg_ccache_name);
+        err = (*out_name == NULL) ? ENOMEM : 0;
     } else {
-        krb5_context context = NULL;
-
-        /* Reset the context default ccache (see text above), and then
-           retrieve it.  */
+        /* Use the default ccache name. */
         err = krb5_gss_init_context(&context);
-        if (!err)
-            err = krb5_cc_set_default_name (context, NULL);
-        if (!err) {
-            name = krb5_cc_default_name(context);
-            if (name) {
-                name = strdup(name);
-                if (name == NULL)
-                    err = ENOMEM;
-            }
-        }
-        if (err && context)
-            save_error_info(err, context);
-        if (context)
-            krb5_free_context(context);
-    }
-
-    if (!err) {
-        if (out_name) {
-            *out_name = name;
-        }
+        if (err)
+            goto cleanup;
+        def_name = krb5_cc_default_name(context);
+        *out_name = (def_name != NULL) ? strdup(def_name) : NULL;
+        err = (*out_name == NULL) ? ENOMEM : 0;
+        krb5_free_context(context);
     }
 
+cleanup:
     *minor_status = err;
     return (*minor_status == 0) ? GSS_S_COMPLETE : GSS_S_FAILURE;
 }
diff --git a/src/lib/gssapi/krb5/set_ccache.c b/src/lib/gssapi/krb5/set_ccache.c
index 8acf3ec..91c3462 100644
--- a/src/lib/gssapi/krb5/set_ccache.c
+++ b/src/lib/gssapi/krb5/set_ccache.c
@@ -26,7 +26,7 @@
 
 /*
  * Set ccache name used by gssapi, and optionally obtain old ccache
- * name.  Caller should not free returned name.
+ * name.  Caller must not free returned name.
  */
 
 #include <string.h>
@@ -38,11 +38,9 @@ gss_krb5int_ccache_name(OM_uint32 *minor_status,
                         const gss_OID desired_object,
                         const gss_buffer_t value)
 {
-    char *old_name = NULL;
     OM_uint32 err = 0;
-    OM_uint32 minor = 0;
-    char *gss_out_name;
     struct krb5_gss_ccache_name_req *req;
+    char *old_name, *cur_name = NULL;
 
     err = gss_krb5int_initialize_library();
     if (err) {
@@ -57,45 +55,33 @@ gss_krb5int_ccache_name(OM_uint32 *minor_status,
 
     req = (struct krb5_gss_ccache_name_req *)value->value;
 
-    gss_out_name = k5_getspecific(K5_KEY_GSS_KRB5_SET_CCACHE_OLD_NAME);
+    /* Our job is simple if the caller doesn't want the current name. */
+    if (req->out_name == NULL)
+        return kg_set_ccache_name(minor_status, req->name);
 
-    if (req->out_name) {
-        const char *tmp_name = NULL;
+    /* Fetch the current name and change it. */
+    kg_get_ccache_name(&err, &cur_name);
+    if (err)
+        goto cleanup;
+    kg_set_ccache_name(&err, req->name);
+    if (err)
+        goto cleanup;
 
-        if (!err) {
-            kg_get_ccache_name (&err, &tmp_name);
-        }
-        if (!err) {
-            old_name = gss_out_name;
-            gss_out_name = (char *)tmp_name;
-        }
-    }
-    /* If out_name was NULL, we keep the same gss_out_name value, and
-       don't free up any storage (leave old_name NULL).  */
-
-    if (!err)
-        kg_set_ccache_name (&err, req->name);
-
-    minor = k5_setspecific(K5_KEY_GSS_KRB5_SET_CCACHE_OLD_NAME, gss_out_name);
-    if (minor) {
-        /* Um.  Now what?  */
-        if (err == 0) {
-            err = minor;
-        }
-        free(gss_out_name);
-        gss_out_name = NULL;
-    }
+    /* Store the current name in a thread-specific variable.  Free that
+     * variable's previous contents. */
+    old_name = k5_getspecific(K5_KEY_GSS_KRB5_SET_CCACHE_OLD_NAME);
+    err = k5_setspecific(K5_KEY_GSS_KRB5_SET_CCACHE_OLD_NAME, cur_name);
+    if (err)
+        goto cleanup;
+    free(old_name);
 
-    if (!err) {
-        if (req->out_name) {
-            *(req->out_name) = gss_out_name;
-        }
-    }
-
-    if (old_name != NULL) {
-        free (old_name);
-    }
+    /* Give the caller an alias to the stored value. */
+    *req->out_name = cur_name;
+    cur_name = NULL;
+    err = 0;
 
+cleanup:
+    free(cur_name);
     *minor_status = err;
     return (*minor_status == 0) ? GSS_S_COMPLETE : GSS_S_FAILURE;
 }