[coreboot-gerrit] Patch set updated for coreboot: aeb2854 Intel: Return on missing microcode file to fix null pointer dereference

[Vladimir Serbinenko]

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

-gerrit

commit aeb285408b849f9542f84e94e92946c195749fed
Author: Vladimir Serbinenko 
Date:   Sat Mar 30 12:04:23 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 | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/cpu/intel/microcode/microcode.c b/src/cpu/intel/microcode/microcode.c
index d908c25..82ab7a2 100644
--- a/src/cpu/intel/microcode/microcode.c
+++ b/src/cpu/intel/microcode/microcode.c
@@ -130,6 +130,9 @@ const void *intel_microcode_find(void)
    				       CBFS_TYPE_MICROCODE);
 #endif

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

@@ -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;