fabrics: Filter out invalid UUIDs from DMI

Qemu might not initialize the system DMI correctly and nvme-cli would
generate an invalid hostid.

Signed-off-by: Daniel Wagner <dwagner@suse.de>

diff --git a/src/nvme/fabrics.c b/src/nvme/fabrics.c
index d6ae33516f37b7db951021d9ca9c343ccaa2e3e5..3c32e2715c9373edb6e3a54b975b12ab71913d40 100644 (file)
--- a/src/nvme/fabrics.c
+++ b/src/nvme/fabrics.c
@@ -1018,6 +1018,25 @@ static int uuid_from_device_tree(char *system_uuid)
  */
 #define DMI_SYSTEM_INFORMATION 1
 
+static bool is_dmi_uuid_valid(const char *buf, size_t len)
+{
+       int i;
+
+       /* UUID bytes are from byte 8 to 23 */
+       if (len < 24)
+               return false;
+
+       /* Test it's a invalid UUID with all zeros */
+       for (i = 8; i < 24; i++) {
+               if (buf[i])
+                       break;
+       }
+       if (i == 24)
+               return false;
+
+       return true;
+}
+
 static int uuid_from_dmi_entries(char *system_uuid)
 {
        int f;
@@ -1053,8 +1072,10 @@ static int uuid_from_dmi_entries(char *system_uuid)
                        continue;
                len = read(f, buf, 512);
                close(f);
-               if (len <= 0)
+
+               if (!is_dmi_uuid_valid(buf, len))
                        continue;
+
                /* Sigh. https://en.wikipedia.org/wiki/Overengineering */
                /* DMTF SMBIOS 3.0 Section 7.2.1 System UUID */
                sprintf(system_uuid,