[S] Change in coreboot[main]: util/cbmem/cbmem.c: Avoid overflows when parsing TCG TPM logs

[Michał Żygowski (Code Review)]

Attention is currently required from: Michał Żygowski.

Hello build bot (Jenkins),

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/84926?usp=email

to look at the new patch set (#3).

Change subject: util/cbmem/cbmem.c: Avoid overflows when parsing TCG TPM logs
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util/cbmem/cbmem.c: Avoid overflows when parsing TCG TPM logs

The utility assumed that TCG TPM log area is zeroed and then filled
with events but it does not have to be true. If there is garbage
after the last valid event entry, the utility will most likely
access data outside of the cbmem area containing the logs. Relevant
issue: https://github.com/linuxboot/heads/issues/1608

TEST=Dump TCG TPM1.2 event log on Dell OptiPlex 7010 with 'cbmem -L'
and see "Invalid TPM1.2 log entry overflowing cbmem area" error is
printed.

Change-Id: I7e057db3378b701d046d4e578272b10f294142a7
Signed-off-by: Michał Żygowski 
---
M util/cbmem/cbmem.c
1 file changed, 17 insertions(+), 6 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/26/84926/3