From 13caff572d54d5fffe1c9b33853a3475d45f6504 Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Tue, 1 Mar 2022 21:51:15 +0100
Subject: [PATCH] glib-aux: avoid nm_crypto_md5_hash() in
 nm_uuid_generate_from_string()

What nm_uuid_generate_from_string() does, is pretty straight forward.
What nm_crypto_md5_hash() does, is not.

Just directly use GChecksum, it seems clearer.

Also, sometimes the compiler is adamant to warn about uninitialized variables.
The workaround from commit cb9ca67901b3 ('glib-aux: workaround maybe-uninitialized
warning with LTO in nm_uuid_generate_from_string_str()') does not always work.
Try to solve that this way.

Note that we have plenty of unit tests for our UUID generation. This is
covered by tests.

Also, there is now only one caller of nm_crypto_md5_hash() left. Which
is good, because that function is rather non-obvious and special purpose.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1129
---
 src/libnm-glib-aux/nm-uuid.c | 74 ++++++++++++++++++++----------------
 1 file changed, 42 insertions(+), 32 deletions(-)

diff --git a/src/libnm-glib-aux/nm-uuid.c b/src/libnm-glib-aux/nm-uuid.c
index 19b096670b..ff0649d0fe 100644
--- a/src/libnm-glib-aux/nm-uuid.c
+++ b/src/libnm-glib-aux/nm-uuid.c
@@ -316,8 +316,20 @@ nm_uuid_generate_from_string(NMUuid       *uuid,
                              NMUuidType    uuid_type,
                              const NMUuid *type_args)
 {
-    g_return_val_if_fail(uuid, FALSE);
-    g_return_val_if_fail(slen == 0 || s, FALSE);
+    nm_auto_free_checksum GChecksum *sum = NULL;
+    union {
+        guint8 sha1[NM_UTILS_CHECKSUM_LENGTH_SHA1];
+        guint8 md5[NM_UTILS_CHECKSUM_LENGTH_MD5];
+        NMUuid uuid;
+    } digest;
+    gsize         digest_len;
+    GChecksumType checksum_type;
+
+    G_STATIC_ASSERT_EXPR(sizeof(digest.md5) >= sizeof(digest.uuid));
+    G_STATIC_ASSERT_EXPR(sizeof(digest.sha1) >= sizeof(digest.uuid));
+
+    g_return_val_if_fail(uuid, NULL);
+    g_return_val_if_fail(slen <= 0 || s, NULL);
 
     if (slen < 0)
         slen = s ? strlen(s) : 0;
@@ -325,45 +337,43 @@ nm_uuid_generate_from_string(NMUuid       *uuid,
     switch (uuid_type) {
     case NM_UUID_TYPE_LEGACY:
         nm_assert(!type_args);
-        nm_crypto_md5_hash(NULL, 0, (guint8 *) s, slen, (guint8 *) uuid, sizeof(*uuid));
+        type_args     = NULL;
+        checksum_type = G_CHECKSUM_MD5;
         break;
     case NM_UUID_TYPE_VERSION3:
-    case NM_UUID_TYPE_VERSION5:
-    {
         if (!type_args)
             type_args = &nm_uuid_ns_zero;
-
-        if (uuid_type == NM_UUID_TYPE_VERSION3) {
-            nm_crypto_md5_hash((guint8 *) s,
-                               slen,
-                               (guint8 *) type_args,
-                               sizeof(*type_args),
-                               (guint8 *) uuid,
-                               sizeof(*uuid));
-        } else {
-            nm_auto_free_checksum GChecksum *sum = NULL;
-            union {
-                guint8 sha1[NM_UTILS_CHECKSUM_LENGTH_SHA1];
-                NMUuid uuid;
-            } digest;
-
-            sum = g_checksum_new(G_CHECKSUM_SHA1);
-            g_checksum_update(sum, (guchar *) type_args, sizeof(*type_args));
-            g_checksum_update(sum, (guchar *) s, slen);
-            nm_utils_checksum_get_digest(sum, digest.sha1);
-
-            G_STATIC_ASSERT_EXPR(sizeof(digest.sha1) > sizeof(digest.uuid));
-            *uuid = digest.uuid;
-        }
-
-        uuid->uuid[6] = (uuid->uuid[6] & 0x0F) | (uuid_type << 4);
-        uuid->uuid[8] = (uuid->uuid[8] & 0x3F) | 0x80;
+        checksum_type = G_CHECKSUM_MD5;
+        break;
+    case NM_UUID_TYPE_VERSION5:
+        if (!type_args)
+            type_args = &nm_uuid_ns_zero;
+        checksum_type = G_CHECKSUM_SHA1;
         break;
-    }
     default:
         g_return_val_if_reached(NULL);
     }
 
+    sum = g_checksum_new(checksum_type);
+    if (type_args)
+        g_checksum_update(sum, (guchar *) type_args, sizeof(*type_args));
+    g_checksum_update(sum, (guchar *) s, slen);
+
+    digest_len = sizeof(digest);
+    g_checksum_get_digest(sum, (guint8 *) &digest, &digest_len);
+
+    nm_assert(digest_len >= sizeof(digest.uuid));
+    nm_assert(digest_len
+              == ((checksum_type == G_CHECKSUM_MD5 ? NM_UTILS_CHECKSUM_LENGTH_MD5
+                                                   : NM_UTILS_CHECKSUM_LENGTH_SHA1)));
+
+    *uuid = digest.uuid;
+
+    if (uuid_type != NM_UUID_TYPE_LEGACY) {
+        uuid->uuid[6] = (uuid->uuid[6] & 0x0F) | (uuid_type << 4);
+        uuid->uuid[8] = (uuid->uuid[8] & 0x3F) | 0x80;
+    }
+
     return uuid;
 }