e1000e: write protect ICHx NVM to prevent malicious write/erase

Set the hardware to ignore all write/erase cycles to the GbE region in
the ICHx NVM.  This feature can be disabled by the WriteProtectNVM module
parameter (enabled by default) only after a hardware reset, but
the machine must be power cycled before trying to enable writes.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
CC: arjan@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/net/e1000e/param.c b/drivers/net/e1000e/param.c
index ed912e023a72..d91dbf7ba434 100644
--- a/drivers/net/e1000e/param.c
+++ b/drivers/net/e1000e/param.c
@@ -133,6 +133,15 @@ E1000_PARAM(SmartPowerDownEnable, "Enable PHY smart power down");
  */
 E1000_PARAM(KumeranLockLoss, "Enable Kumeran lock loss workaround");
 
+/*
+ * Write Protect NVM
+ *
+ * Valid Range: 0, 1
+ *
+ * Default Value: 1 (enabled)
+ */
+E1000_PARAM(WriteProtectNVM, "Write-protect NVM [WARNING: disabling this can lead to corrupted NVM]");
+
 struct e1000_option {
         enum { enable_option, range_option, list_option } type;
         const char *name;
@@ -388,4 +397,25 @@ void __devinit e1000e_check_options(struct e1000_adapter *adapter)
                                                                        opt.def);
                 }
         }
+        { /* Write-protect NVM */
+                const struct e1000_option opt = {
+                        .type = enable_option,
+                        .name = "Write-protect NVM",
+                        .err  = "defaulting to Enabled",
+                        .def  = OPTION_ENABLED
+                };
+
+                if (adapter->flags & FLAG_IS_ICH) {
+                        if (num_WriteProtectNVM > bd) {
+                                unsigned int write_protect_nvm = WriteProtectNVM[bd];
+                                e1000_validate_option(&write_protect_nvm, &opt,
+                                                      adapter);
+                                if (write_protect_nvm)
+                                        adapter->flags |= FLAG_READ_ONLY_NVM;
+                        } else {
+                                if (opt.def)
+                                        adapter->flags |= FLAG_READ_ONLY_NVM;
+                        }
+                }
+        }
 }