File shim-bsc1185232-fix-config-table-copying.patch of Package shim.19526

From 42c6148c7ebd026862ab96405e78191ff8ebf298 Mon Sep 17 00:00:00 2001
From: Gary Lin <glin@suse.com>
Date: Mon, 21 Jun 2021 16:38:02 +0800
Subject: [PATCH] mok: skip the empty variables when copying the data to MOK
 config table

When calculating the size of the MOK config table, we skip the empty
variables. However, when copying the data, we copied the zeroed config
templates for those empty variables, and this could cause crash since we
may write more data than the allocated pages. This commit skips the
empty variables when copying the data so that the size of copied data
matches config_sz.

Signed-off-by: Gary Lin <glin@suse.com>
---
 mok.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/mok.c b/mok.c
index beac0ff6..add21223 100644
--- a/mok.c
+++ b/mok.c
@@ -1028,16 +1028,18 @@ EFI_STATUS import_mok_state(EFI_HANDLE image_handle)
 	for (i = 0; p && mok_state_variables[i].name != NULL; i++) {
 		struct mok_state_variable *v = &mok_state_variables[i];
 
-		ZeroMem(&config_template, sizeof(config_template));
-		strncpy(config_template.name, (CHAR8 *)v->rtname8, 255);
-		config_template.name[255] = '\0';
+		if (v->data && v->data_size) {
+			ZeroMem(&config_template, sizeof(config_template));
+			strncpy(config_template.name, (CHAR8 *)v->rtname8, 255);
+			config_template.name[255] = '\0';
 
-		config_template.data_size = v->data_size;
+			config_template.data_size = v->data_size;
 
-		CopyMem(p, &config_template, sizeof(config_template));
-		p += sizeof(config_template);
-		CopyMem(p, v->data, v->data_size);
-		p += v->data_size;
+			CopyMem(p, &config_template, sizeof(config_template));
+			p += sizeof(config_template);
+			CopyMem(p, v->data, v->data_size);
+			p += v->data_size;
+		}
 	}
 	if (p) {
 		ZeroMem(&config_template, sizeof(config_template));
-- 
2.31.1