svn commit: r345288 - head/sys/amd64/sgx

[Marcin Wojtas]

Author: mw
Date: Tue Mar 19 02:33:58 2019
New Revision: 345288
URL: https://svnweb.freebsd.org/changeset/base/345288

Log:
  Prevent loading SGX with incorrect EPC data
  
  It may happen on some machines, that even if SGX is disabled
  in firmware, the driver would still attach despite EPC base and
  size equal zero. Such behaviour causes a kernel panic when the
  module is unloaded. Add a simple check to make sure we
  only attach when these values are correctly set.
  
  Submitted by: Kornel Duleba <mindal at semihalf.com>
  Reviewed by: br
  Obtained from: Semihalf
  Sponsored by: Stormshield
  Differential Revision: https://reviews.freebsd.org/D19595

Modified:
  head/sys/amd64/sgx/sgx.c

Modified: head/sys/amd64/sgx/sgx.c
==============================================================================
--- head/sys/amd64/sgx/sgx.c	Tue Mar 19 00:29:18 2019	(r345287)
+++ head/sys/amd64/sgx/sgx.c	Tue Mar 19 02:33:58 2019	(r345288)
@@ -1075,6 +1075,12 @@ sgx_get_epc_area(struct sgx_softc *sc)
 	    (cp[2] & 0xfffff000);
 	sc->npages = sc->epc_size / SGX_PAGE_SIZE;
 
+	if (sc->epc_size == 0 || sc->epc_base == 0) {
+		printf("%s: Incorrect EPC data: EPC base %lx, size %lu\n",
+		    __func__, sc->epc_base, sc->epc_size);
+		return (EINVAL);
+	}
+
 	if (cp[3] & 0xffff)
 		sc->enclave_size_max = (1 << ((cp[3] >> 8) & 0xff));
 	else