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 (file)
--- 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 (file)
--- 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;