target: prevent NULL pointer dereference in target_report_luns

commit 47f1b8803e1e358ebbf4f82bfdb98971c912a2c3 upstream.

transport_kmap_data_sg can return NULL.  I never saw this trigger, but
returning -ENOMEM seems better than a crash.  Also removes a pointless
case while at it.

Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 097178b..f8773ae 100644 (file)
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -658,7 +658,9 @@ int target_report_luns(struct se_task *se_task)
        unsigned char *buf;
        u32 cdb_offset = 0, lun_count = 0, offset = 8, i;
 
-       buf = (unsigned char *) transport_kmap_data_sg(se_cmd);
+       buf = transport_kmap_data_sg(se_cmd);
+       if (!buf)
+               return -ENOMEM;
 
        /*
         * If no struct se_session pointer is present, this struct se_cmd is