libuuid: fix name-based UUIDs

The current version is not fully compatible with RFC4122. It
incorrectly encodes UUID variant

	xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx

where M is UUID version and N is UUID variant.

 $ python -c "import uuid ; print(uuid.uuid5(uuid.UUID(int=0), 'foo'))"
 aa752cea-8222-5bc8-acd9-555b090c0ccb
                    ^^

Old version:

 $ uuidgen --namespace 00000000-0000-0000-0000-000000000000 --name 'foo' --sha1
 aa752cea-8222-5bc8-8cd9-555b090c0ccb
                    ^^

Fixed version:
 ./uuidgen --namespace 00000000-0000-0000-0000-000000000000 --name 'foo' --sha1;
 aa752cea-8222-5bc8-acd9-555b090c0ccb
                    ^^

The patch uses uuid_unpack and uuid_pack. It makes code more readable
and allow to access proper octens. The same way we already use for
time and random based UUIDs.

Addresses: https://github.com/karelzak/util-linux/issues/683
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libuuid/src/gen_uuid.c b/libuuid/src/gen_uuid.c
index a374e75c9e3d38af0b06cf38acf4d0012ed339a4..27c135db5936baeb0f28d4e7ee80d00ed50dbe84 100644 (file)
--- a/libuuid/src/gen_uuid.c
+++ b/libuuid/src/gen_uuid.c
@@ -96,9 +96,6 @@
 #define THREAD_LOCAL static
 #endif
 
-/* index with UUID_VARIANT_xxx and shift 5 bits */
-static unsigned char variant_bits[] = { 0x00, 0x04, 0x06, 0x07 };
-
 #ifdef _WIN32
 static void gettimeofday (struct timeval *tv, void *dummy)
 {
@@ -566,21 +563,22 @@ void uuid_generate_md5(uuid_t out, const uuid_t ns, const char *name, size_t len
 {
        UL_MD5_CTX ctx;
        char hash[UL_MD5LENGTH];
+       uuid_t buf;
+       struct uuid uu;
 
        ul_MD5Init(&ctx);
-       /* hash concatenation of well-known UUID with name */
        ul_MD5Update(&ctx, ns, sizeof(uuid_t));
        ul_MD5Update(&ctx, (const unsigned char *)name, len);
-
        ul_MD5Final((unsigned char *)hash, &ctx);
 
-       memcpy(out, hash, sizeof(uuid_t));
+       assert(sizeof(buf) <= sizeof(hash));
 
-       out[6] &= ~(UUID_TYPE_MASK << UUID_TYPE_SHIFT);
-       out[6] |= (UUID_TYPE_DCE_MD5 << UUID_TYPE_SHIFT);
+       memcpy(buf, hash, sizeof(buf));
+       uuid_unpack(buf, &uu);
 
-       out[8] &= ~(UUID_VARIANT_MASK << UUID_VARIANT_SHIFT);
-       out[8] |= (variant_bits[UUID_VARIANT_DCE] << UUID_VARIANT_SHIFT);
+       uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
+       uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | 0x3000;
+       uuid_pack(&uu, out);
 }
 
 /*
@@ -591,20 +589,20 @@ void uuid_generate_sha1(uuid_t out, const uuid_t ns, const char *name, size_t le
 {
        UL_SHA1_CTX ctx;
        char hash[UL_SHA1LENGTH];
+       uuid_t buf;
+       struct uuid uu;
 
        ul_SHA1Init(&ctx);
-       /* hash concatenation of well-known UUID with name */
        ul_SHA1Update(&ctx, ns, sizeof(uuid_t));
        ul_SHA1Update(&ctx, (const unsigned char *)name, len);
-
        ul_SHA1Final((unsigned char *)hash, &ctx);
 
-       memcpy(out, hash, sizeof(uuid_t));
+       assert(sizeof(buf) <= sizeof(hash));
 
-       out[6] &= ~(UUID_TYPE_MASK << UUID_TYPE_SHIFT);
-       out[6] |= (UUID_TYPE_DCE_SHA1 << UUID_TYPE_SHIFT);
+       memcpy(buf, hash, sizeof(buf));
+       uuid_unpack(buf, &uu);
 
-       out[8] &= ~(UUID_VARIANT_MASK << UUID_VARIANT_SHIFT);
-       out[8] |= (variant_bits[UUID_VARIANT_DCE] << UUID_VARIANT_SHIFT);
+       uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
+       uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | 0x5000;
+       uuid_pack(&uu, out);
 }
-