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path: root/src/lib/tpm2_marshaling.h
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2016-07-13tpm2: avoid comparison between signed and unsigned intsVadim Bendebury
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@chromium.org> Original-Commit-Id: b1e862c2a650fa5f6cb25a01fe61e848a696cf17 Original-Change-Id: Ie7552b333afaff9a1234c948caf9d9a64447b2e1 Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/358772 Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: https://review.coreboot.org/15610 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2016-07-11tpm2: add marshaling/unmarshaling layerVadim Bendebury
TPM commands need to be serialized (marshaled) to be sent to the device, and the responses need to be de-serialized (unmarshaled) to be properly interpreted by upper layers. This layer does not exist in TPM1.2 coreboot implementation, all TPM commands used there were hardcoded as binary arrays. Availability of the marshaling/unmarshaling layer makes it much easier to add new TPM commands to the code. Command and response structures used in these functions are defined in Parts 2 and 3 of the TCG issued document Trusted Platform Module Library Family "2.0" Level 00 Revision 01.16 October 30, 2014 BRANCH=none BUG=chrome-os-partner:50645 TEST=with the rest of the patches applied it is possible to successfully initialize firmware and kernel TPM spaces. Change-Id: I80b3f971e347bb30ea08f820ec3dd27e1656c060 Signed-off-by: Martin Roth <martinroth@chromium.org> Original-Commit-Id: 0782d9d452efb732e85d1503fccfcb4bf9f69a68 Original-Change-Id: I202276ef9a43c28b5f304f901ac5b91048878b76 Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/353915 Original-Reviewed-by: Bill Richardson <wfrichar@chromium.org> Original-Reviewed-by: Darren Krahn <dkrahn@chromium.org> Reviewed-on: https://review.coreboot.org/15570 Tested-by: build bot (Jenkins) Reviewed-by: Furquan Shaikh <furquan@google.com> Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@googlemail.com>