From 0f7c9a3d81becec899a082e8258bd12001c5ab3a Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 29 Jan 2020 18:08:36 +0100
Subject: [PATCH] dissect: complain if partition flags are set that we don't
 know

---
 src/shared/dissect-image.c | 45 ++++++++++++++++++++++++++++++++++++++
 src/shared/gpt.h           |  2 ++
 2 files changed, 47 insertions(+)

diff --git a/src/shared/dissect-image.c b/src/shared/dissect-image.c
index 087c3dc345..62aa42d013 100644
--- a/src/shared/dissect-image.c
+++ b/src/shared/dissect-image.c
@@ -278,6 +278,29 @@ static int loop_wait_for_partitions_to_appear(
                                N_DEVICE_NODE_LIST_ATTEMPTS);
 }
 
+static void check_partition_flags(
+                const char *node,
+                unsigned long long pflags,
+                unsigned long long supported) {
+
+        assert(node);
+
+        /* Mask away all flags supported by this partition's type and the three flags the UEFI spec defines generically */
+        pflags &= ~(supported | GPT_FLAG_REQUIRED_PARTITION | GPT_FLAG_NO_BLOCK_IO_PROTOCOL | GPT_FLAG_LEGACY_BIOS_BOOTABLE);
+
+        if (pflags == 0)
+                return;
+
+        /* If there are other bits set, then log about it, to make things discoverable */
+        for (unsigned i = 0; i < sizeof(pflags) * 8; i++) {
+                unsigned long long bit = 1ULL << i;
+                if (!FLAGS_SET(pflags, bit))
+                        continue;
+
+                log_debug("Unexpected partition flag %llu set on %s!", bit, node);
+        }
+}
+
 #endif
 
 int dissect_image(
@@ -484,6 +507,8 @@ int dissect_image(
 
                         if (sd_id128_equal(type_id, GPT_HOME)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -491,6 +516,8 @@ int dissect_image(
                                 rw = !(pflags & GPT_FLAG_READ_ONLY);
                         } else if (sd_id128_equal(type_id, GPT_SRV)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -510,6 +537,8 @@ int dissect_image(
 
                         } else if (sd_id128_equal(type_id, GPT_XBOOTLDR)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -519,6 +548,8 @@ int dissect_image(
 #ifdef GPT_ROOT_NATIVE
                         else if (sd_id128_equal(type_id, GPT_ROOT_NATIVE)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -531,6 +562,8 @@ int dissect_image(
                                 rw = !(pflags & GPT_FLAG_READ_ONLY);
                         } else if (sd_id128_equal(type_id, GPT_ROOT_NATIVE_VERITY)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -549,6 +582,8 @@ int dissect_image(
 #ifdef GPT_ROOT_SECONDARY
                         else if (sd_id128_equal(type_id, GPT_ROOT_SECONDARY)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -561,6 +596,8 @@ int dissect_image(
                                 rw = !(pflags & GPT_FLAG_READ_ONLY);
                         } else if (sd_id128_equal(type_id, GPT_ROOT_SECONDARY_VERITY)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -578,6 +615,8 @@ int dissect_image(
 #endif
                         else if (sd_id128_equal(type_id, GPT_SWAP)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -585,6 +624,8 @@ int dissect_image(
                                 fstype = "swap";
                         } else if (sd_id128_equal(type_id, GPT_LINUX_GENERIC)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -601,6 +642,8 @@ int dissect_image(
 
                         } else if (sd_id128_equal(type_id, GPT_TMP)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
@@ -609,6 +652,8 @@ int dissect_image(
 
                         } else if (sd_id128_equal(type_id, GPT_VAR)) {
 
+                                check_partition_flags(node, pflags, GPT_FLAG_NO_AUTO|GPT_FLAG_READ_ONLY);
+
                                 if (pflags & GPT_FLAG_NO_AUTO)
                                         continue;
 
diff --git a/src/shared/gpt.h b/src/shared/gpt.h
index dcceb076d6..6863dcb81c 100644
--- a/src/shared/gpt.h
+++ b/src/shared/gpt.h
@@ -57,7 +57,9 @@
 #  define GPT_ROOT_NATIVE_VERITY GPT_ROOT_ARM_VERITY
 #endif
 
+#define GPT_FLAG_REQUIRED_PARTITION (1ULL << 0)
 #define GPT_FLAG_NO_BLOCK_IO_PROTOCOL (1ULL << 1)
+#define GPT_FLAG_LEGACY_BIOS_BOOTABLE (1ULL << 2)
 
 /* Flags we recognize on the root, swap, home and srv partitions when
  * doing auto-discovery. These happen to be identical to what