From: AKASHI Takahiro <takahiro.akashi@linaro.org>
Date: Fri, 24 May 2019 06:59:03 +0000 (+0900)
Subject: efi_loader: variable: attributes may not be changed if a variable exists
X-Git-Tag: v2019.07-rc3~6^2
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=a2c6983740104c8e608c411eff6a58e2f4feaede;p=oweals%2Fu-boot.git

efi_loader: variable: attributes may not be changed if a variable exists

If a variable already exists, efi_set_variable() should not change
the variable's attributes. This patch enforces it.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---

diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 0d973773fa..50bc10537f 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -451,12 +451,21 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
 	if (val) {
 		parse_attr(val, &attr);
 
+		/* We should not free val */
+		val = NULL;
 		if (attr & READ_ONLY) {
-			/* We should not free val */
-			val = NULL;
 			ret = EFI_WRITE_PROTECTED;
 			goto out;
 		}
+
+		/*
+		 * attributes won't be changed
+		 * TODO: take care of APPEND_WRITE once supported
+		 */
+		if (attr != attributes) {
+			ret = EFI_INVALID_PARAMETER;
+			goto out;
+		}
 	}
 
 	val = malloc(2 * data_size + strlen("{ro,run,boot}(blob)") + 1);