From cea4dcfdad926a27a18e188720efe0f2c9403456 Mon Sep 17 00:00:00 2001
From: Kees Cook <keescook@chromium.org>
Date: Thu, 23 May 2013 17:32:17 +0000
Subject: iscsi-target: fix heap buffer overflow on error

If a key was larger than 64 bytes, as checked by iscsi_check_key(), the
error response packet, generated by iscsi_add_notunderstood_response(),
would still attempt to copy the entire key into the packet, overflowing
the structure on the heap.

Remote preauthentication kernel memory corruption was possible if a
target was configured and listening on the network.

CVE-2013-2850

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
diff --git a/drivers/target/iscsi/iscsi_target_parameters.c b/drivers/target/iscsi/iscsi_target_parameters.c
index c2185fc..e382221 100644
--- a/drivers/target/iscsi/iscsi_target_parameters.c
+++ b/drivers/target/iscsi/iscsi_target_parameters.c
@@ -758,9 +758,9 @@ static int iscsi_add_notunderstood_response(
 	}
 	INIT_LIST_HEAD(&extra_response->er_list);
 
-	strncpy(extra_response->key, key, strlen(key) + 1);
-	strncpy(extra_response->value, NOTUNDERSTOOD,
-			strlen(NOTUNDERSTOOD) + 1);
+	strlcpy(extra_response->key, key, sizeof(extra_response->key));
+	strlcpy(extra_response->value, NOTUNDERSTOOD,
+		sizeof(extra_response->value));
 
 	list_add_tail(&extra_response->er_list,
 			&param_list->extra_response_list);
@@ -1629,8 +1629,6 @@ int iscsi_decode_text_input(
 
 		if (phase & PHASE_SECURITY) {
 			if (iscsi_check_for_auth_key(key) > 0) {
-				char *tmpptr = key + strlen(key);
-				*tmpptr = '=';
 				kfree(tmpbuf);
 				return 1;
 			}
diff --git a/drivers/target/iscsi/iscsi_target_parameters.h b/drivers/target/iscsi/iscsi_target_parameters.h
index 915b067..a47046a 100644
--- a/drivers/target/iscsi/iscsi_target_parameters.h
+++ b/drivers/target/iscsi/iscsi_target_parameters.h
@@ -1,8 +1,10 @@
 #ifndef ISCSI_PARAMETERS_H
 #define ISCSI_PARAMETERS_H
 
+#include <scsi/iscsi_proto.h>
+
 struct iscsi_extra_response {
-	char key[64];
+	char key[KEY_MAXLEN];
 	char value[32];
 	struct list_head er_list;
 } ____cacheline_aligned;
--
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