nspawn/dissect: automatically discover dm-verity verity partitions

This adds support for discovering and making use of properly tagged dm-verity
data integrity partitions. This extends both systemd-nspawn and systemd-dissect
with a new --root-hash= switch that takes the root hash to use for the root
partition, and is otherwise fully automatic.

Verity partitions are discovered automatically by GPT table type UUIDs, as
listed in
https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/
(which I updated prior to this change, to include new UUIDs for this purpose.

mkosi with https://github.com/systemd/mkosi/pull/39 applied may generate images
that carry the necessary integrity data. With that PR and this commit, the
following simply lines suffice to boot up an integrity-protected container image:

```
 # mkdir test
 # cd test
 # mkosi --verity
 # systemd-nspawn -i ./image.raw -bn
```

Note that mkosi writes the image file to "image.raw" next to a a file
"image.roothash" that contains the root hash. systemd-nspawn will look for that
file and use it if it exists, in case --root-hash= is not specified explicitly.

1 files changed, 16 insertions, 1 deletions

diff --git a/src/shared/gpt.h b/src/shared/gpt.h
index 55b41bbcd8..13d80d611c 100644
--- a/src/shared/gpt.h
+++ b/src/shared/gpt.h
@@ -32,28 +32,43 @@
 #define GPT_ROOT_ARM    SD_ID128_MAKE(69,da,d7,10,2c,e4,4e,3c,b1,6c,21,a1,d4,9a,be,d3)
 #define GPT_ROOT_ARM_64 SD_ID128_MAKE(b9,21,b0,45,1d,f0,41,c3,af,44,4c,6f,28,0d,3f,ae)
 #define GPT_ROOT_IA64   SD_ID128_MAKE(99,3d,8d,3d,f8,0e,42,25,85,5a,9d,af,8e,d7,ea,97)
-
 #define GPT_ESP         SD_ID128_MAKE(c1,2a,73,28,f8,1f,11,d2,ba,4b,00,a0,c9,3e,c9,3b)
 #define GPT_SWAP        SD_ID128_MAKE(06,57,fd,6d,a4,ab,43,c4,84,e5,09,33,c8,4b,4f,4f)
 #define GPT_HOME        SD_ID128_MAKE(93,3a,c7,e1,2e,b4,4f,13,b8,44,0e,14,e2,ae,f9,15)
 #define GPT_SRV         SD_ID128_MAKE(3b,8f,84,25,20,e0,4f,3b,90,7f,1a,25,a7,6f,98,e8)
 
+/* Verity partitions for the root partitions above (we only define them for the root partitions, because only they are
+ * are commonly read-only and hence suitable for verity). */
+#define GPT_ROOT_X86_VERITY    SD_ID128_MAKE(d1,3c,5d,3b,b5,d1,42,2a,b2,9f,94,54,fd,c8,9d,76)
+#define GPT_ROOT_X86_64_VERITY SD_ID128_MAKE(2c,73,57,ed,eb,d2,46,d9,ae,c1,23,d4,37,ec,2b,f5)
+#define GPT_ROOT_ARM_VERITY    SD_ID128_MAKE(73,86,cd,f2,20,3c,47,a9,a4,98,f2,ec,ce,45,a2,d6)
+#define GPT_ROOT_ARM_64_VERITY SD_ID128_MAKE(df,33,00,ce,d6,9f,4c,92,97,8c,9b,fb,0f,38,d8,20)
+#define GPT_ROOT_IA64_VERITY   SD_ID128_MAKE(86,ed,10,d5,b6,07,45,bb,89,57,d3,50,f2,3d,05,71)
+
+
 #if defined(__x86_64__)
 #  define GPT_ROOT_NATIVE GPT_ROOT_X86_64
 #  define GPT_ROOT_SECONDARY GPT_ROOT_X86
+#  define GPT_ROOT_NATIVE_VERITY GPT_ROOT_X86_64_VERITY
+#  define GPT_ROOT_SECONDARY_VERITY GPT_ROOT_X86_VERITY
 #elif defined(__i386__)
 #  define GPT_ROOT_NATIVE GPT_ROOT_X86
+#  define GPT_ROOT_NATIVE_VERITY GPT_ROOT_X86_VERITY
 #endif
 
 #if defined(__ia64__)
 #  define GPT_ROOT_NATIVE GPT_ROOT_IA64
+#  define GPT_ROOT_NATIVE_VERITY GPT_ROOT_IA64_VERITY
 #endif
 
 #if defined(__aarch64__) && (__BYTE_ORDER != __BIG_ENDIAN)
 #  define GPT_ROOT_NATIVE GPT_ROOT_ARM_64
 #  define GPT_ROOT_SECONDARY GPT_ROOT_ARM
+#  define GPT_ROOT_NATIVE_VERITY GPT_ROOT_ARM_64_VERITY
+#  define GPT_ROOT_SECONDARY_VERITY GPT_ROOT_ARM_VERITY
 #elif defined(__arm__) && (__BYTE_ORDER != __BIG_ENDIAN)
 #  define GPT_ROOT_NATIVE GPT_ROOT_ARM
+#  define GPT_ROOT_NATIVE_VERITY GPT_ROOT_ARM_VERITY
 #endif
 
 /* Flags we recognize on the root, swap, home and srv partitions when