From bbf8235eb297047521ac83b594389d70ecfb38df Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 14 Dec 2022 18:48:52 +0100
Subject: [PATCH] efi: add common implementation for loop finding EFI
 configuration tables

(cherry picked from commit a04709c1ac81b28b1a4144166991ac56be94cfcd)

Related: RHEL-16952
---
 src/boot/efi/devicetree.c  | 11 ++---------
 src/boot/efi/random-seed.c |  6 +-----
 src/boot/efi/util.c        |  8 ++++++++
 src/boot/efi/util.h        |  2 ++
 4 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/src/boot/efi/devicetree.c b/src/boot/efi/devicetree.c
index daba5582aa..12015fce6b 100644
--- a/src/boot/efi/devicetree.c
+++ b/src/boot/efi/devicetree.c
@@ -8,13 +8,6 @@
 
 #define FDT_V1_SIZE (7*4)
 
-static void *get_dtb_table(void) {
-        for (UINTN i = 0; i < ST->NumberOfTableEntries; i++)
-                if (efi_guid_equal(&ST->ConfigurationTable[i].VendorGuid, &EfiDtbTableGuid))
-                        return ST->ConfigurationTable[i].VendorTable;
-        return NULL;
-}
-
 static EFI_STATUS devicetree_allocate(struct devicetree_state *state, UINTN size) {
         UINTN pages = DIV_ROUND_UP(size, EFI_PAGE_SIZE);
         EFI_STATUS err;
@@ -81,7 +74,7 @@ EFI_STATUS devicetree_install(struct devicetree_state *state, EFI_FILE *root_dir
         assert(root_dir);
         assert(name);
 
-        state->orig = get_dtb_table();
+        state->orig = find_configuration_table(&EfiDtbTableGuid);
         if (!state->orig)
                 return EFI_UNSUPPORTED;
 
@@ -121,7 +114,7 @@ EFI_STATUS devicetree_install_from_memory(struct devicetree_state *state,
         assert(state);
         assert(dtb_buffer && dtb_length > 0);
 
-        state->orig = get_dtb_table();
+        state->orig = find_configuration_table(&EfiDtbTableGuid);
         if (!state->orig)
                 return EFI_UNSUPPORTED;
 
diff --git a/src/boot/efi/random-seed.c b/src/boot/efi/random-seed.c
index 6070145778..332f537d91 100644
--- a/src/boot/efi/random-seed.c
+++ b/src/boot/efi/random-seed.c
@@ -146,11 +146,7 @@ EFI_STATUS process_random_seed(EFI_FILE *root_dir) {
         /* Some basic domain separation in case somebody uses this data elsewhere */
         sha256_process_bytes(HASH_LABEL, sizeof(HASH_LABEL) - 1, &hash);
 
-        for (size_t i = 0; i < ST->NumberOfTableEntries; ++i)
-                if (efi_guid_equal(&ST->ConfigurationTable[i].VendorGuid, &(const EFI_GUID) LINUX_EFI_RANDOM_SEED_TABLE_GUID)) {
-                        previous_seed_table = ST->ConfigurationTable[i].VendorTable;
-                        break;
-                }
+        previous_seed_table = find_configuration_table(&(const EFI_GUID) LINUX_EFI_RANDOM_SEED_TABLE_GUID);
         if (!previous_seed_table) {
                 size = 0;
                 sha256_process_bytes(&size, sizeof(size), &hash);
diff --git a/src/boot/efi/util.c b/src/boot/efi/util.c
index 1f07fbc38c..0a6bb59dce 100644
--- a/src/boot/efi/util.c
+++ b/src/boot/efi/util.c
@@ -747,3 +747,11 @@ bool in_hypervisor(void) {
         return !!(ecx & 0x80000000U);
 }
 #endif
+
+void *find_configuration_table(const EFI_GUID *guid) {
+        for (UINTN i = 0; i < ST->NumberOfTableEntries; i++)
+                if (efi_guid_equal(&ST->ConfigurationTable[i].VendorGuid, guid))
+                        return ST->ConfigurationTable[i].VendorTable;
+
+        return NULL;
+}
diff --git a/src/boot/efi/util.h b/src/boot/efi/util.h
index a076f48dba..88fc60c17e 100644
--- a/src/boot/efi/util.h
+++ b/src/boot/efi/util.h
@@ -221,3 +221,5 @@ static inline bool in_hypervisor(void) {
 static inline bool efi_guid_equal(const EFI_GUID *a, const EFI_GUID *b) {
         return memcmp(a, b, sizeof(EFI_GUID)) == 0;
 }
+
+void *find_configuration_table(const EFI_GUID *guid);