[coreboot-gerrit] Patch merged into coreboot/master: tpm2: avoid comparison between signed and unsigned ints

[gerrit at coreboot.org]

the following patch was just integrated into master:
commit bc927107a062ca791ffb4a4f593049a7219b5a07
Author: Vadim Bendebury <vbendeb at chromium.org>
Date:   Thu Jul 7 10:52:46 2016 -0700

    tpm2: avoid comparison between signed and unsigned ints
    
    The marshaling/unmarshaling code is using integer values to represent
    room left in the buffer, to be able to communicate three conditions:
    positive number means there is room left in the buffer, zero means
    that the exact amount of data in the buffer was unmarshaled and
    negative value means that the result of the operation did not fit into
    the buffer.
    
    The implementation is wrong though, as it compares directly signed and
    unsigned values, which is illegal, as signed values get promoted to
    unsigned by the compiler.
    
    This patch changes the marshaling code to use size_t for the size, and
    use zero as marshaling failure indication - after all the buffer where
    the data is marshaled to should definitely be large enough, and it is
    reasonable to expect at least some room left in it after marshaling.
    
    The unmarshaling situation is different: we sure want to communicate
    errors to the caller, but do not want to propagate error return values
    through multiple layers. This patch keeps the size value in int, but
    checks if it is negative separately, before comparing with positive
    values.
    
    BRANCH=none
    BUG=chrome-os-partner:50645
    TEST=with the rest of the patches applied kevin successfully boots up.
    
    Change-Id: Ibfbd1b351e35e37c8925a78d095e4e8492805bad
    Signed-off-by: Martin Roth <martinroth at chromium.org>
    Original-Commit-Id: b1e862c2a650fa5f6cb25a01fe61e848a696cf17
    Original-Change-Id: Ie7552b333afaff9a1234c948caf9d9a64447b2e1
    Original-Signed-off-by: Vadim Bendebury <vbendeb at chromium.org>
    Original-Reviewed-on: https://chromium-review.googlesource.com/358772
    Original-Reviewed-by: Aaron Durbin <adurbin at chromium.org>
    Reviewed-on: https://review.coreboot.org/15610
    Tested-by: build bot (Jenkins)
    Reviewed-by: Patrick Georgi <pgeorgi at google.com>


See https://review.coreboot.org/15610 for details.

-gerrit