[S] Change in coreboot[main]: commonlib/fsp_relocate: Fix potential NULL pointer dereference

[Matt DeVillier (Code Review)]

Matt DeVillier has submitted this change. ( https://review.coreboot.org/c/coreboot/+/78501?usp=email )

Change subject: commonlib/fsp_relocate: Fix potential NULL pointer dereference
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commonlib/fsp_relocate: Fix potential NULL pointer dereference

Commit 1df1cf994aa9 ("commonlib/fsp_relocate: add PE32 section
support") introduced a potential NULL pointer dereference if there is
PE32 binary to relocate outside of the first firmware volume.

The `fih_offset' pointer was used as an output variable but now it is
also used as an input variable to pass the FSP information header to
the `pe_relocate()' function.

This commit resolves this potential NULL-pointer dereference by
passing the pointer systematically and without affecting the logic as
it is only set if it has not been set before.

Change-Id: I9fad90a60854d5f050aa044a5c0b3af91c99df4a
Signed-off-by: Jeremy Compostella 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78501
Reviewed-by: Bora Guvendik 
Reviewed-by: Eric Lai 
Tested-by: build bot (Jenkins) 
---
M src/commonlib/fsp_relocate.c
1 file changed, 3 insertions(+), 9 deletions(-)

Approvals:
  Bora Guvendik: Looks good to me, approved
  Eric Lai: Looks good to me, but someone else must approve
  build bot (Jenkins): Verified

diff --git a/src/commonlib/fsp_relocate.c b/src/commonlib/fsp_relocate.c
index 379930b..96d31b3 100644
--- a/src/commonlib/fsp_relocate.c
+++ b/src/commonlib/fsp_relocate.c
@@ -584,7 +584,7 @@
    	printk(FSP_DBG_LVL, "file offset: %zx\n", file_offset);

/* First file and section should be FSP info header. */
-		if (fih_offset != NULL && *fih_offset == 0)
+		if (*fih_offset == 0)
    		*fih_offset = file_offset;

ffsfh = relative_offset(fsp, file_offset);
@@ -671,14 +671,8 @@
    while (offset < size) {
    	ssize_t nparsed;

-		/* Relocate each FV within the FSP region. The FSP_INFO_HEADER
-		 * should only be located in the first FV. */
-		if (offset == 0)
-			nparsed = relocate_fvh(new_addr, fsp, size, offset,
-						&fih_offset);
-		else
-			nparsed = relocate_fvh(new_addr, fsp, size, offset,
-						NULL);
+		/* Relocate each FV within the FSP region. */
+		nparsed = relocate_fvh(new_addr, fsp, size, offset, &fih_offset);

/* FV should be larger than 0 or failed to parse. */
    	if (nparsed <= 0) {