[coreboot-gerrit] Patch set updated for coreboot: 03da0a9 Intel: Return on missing microcode file to fix null pointer dereference

[Paul Menzel]

Paul Menzel ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/2990

-gerrit

commit 03da0a93e2c653900e19c421c7167202c1afefa6
Author: Vladimir Serbinenko 
Date:   Tue Mar 12 15:53:44 2013 +0100

Intel: Return on missing microcode file to fix null pointer dereference

Selecting `CPU_MICROCODE_IN_CBFS` in Kconfig but not having the
    microcode blob `cpu_microcode_blob.bin` in CBFS results in a
    null pointer dereference later on resulting in a crash.

for(c = microcode_updates; m->hdrver; m = (const struct microcode *)c) {

Fix this by returning if `microcode_updates` is `NULL`, that means
    no file is found.

This patch is successfully tested on the Lenovo X201.

Change-Id: I6e18fd37256910bf047061e4633a66cf29ad7b69
    Signed-off-by: Vladimir Serbinenko 
    Signed-off-by: Paul Menzel 
---
 src/cpu/intel/microcode/microcode.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/cpu/intel/microcode/microcode.c b/src/cpu/intel/microcode/microcode.c
index d908c25..a1f66d8 100644
--- a/src/cpu/intel/microcode/microcode.c
+++ b/src/cpu/intel/microcode/microcode.c
@@ -131,7 +131,10 @@ const void *intel_microcode_find(void)
 #endif

if (!microcode_updates)
-		return microcode_updates;
+		/* No need for an explicit error message since the user
+		 * already gets "file not found" from CBFS.
+		 */
+		return microcode_updates; /* NULL */

/* CPUID sets MSR 0x8B iff a microcode update has been loaded. */
    msr.lo = 0;
@@ -202,6 +205,9 @@ void intel_update_microcode(const void *microcode_updates)
    const char *c;
    msr_t msr;

+	if (!microcode_updates)
+	  return;
+
    /* CPUID sets MSR 0x8B iff a microcode update has been loaded. */
    msr.lo = 0;
    msr.hi = 0;