On Thu, Nov 12, 2020 at 11:57:00PM -0500, Jeff King wrote: > On Thu, Nov 12, 2020 at 06:47:09PM +0100, Martin Ågren wrote: > > > The addition should be ok or mmap has failed on us. Do we know that we > > have room for the final hash there so that the subtraction is ok? Yes, > > from the previous commit, we know we have room for the header, which is > > even larger. But that's cheating a bit -- see below. > > Yeah, I agree this ought to be checking the minimum size against the > header _plus_ the trailer. > > I think the previous patch is actually where it goes wrong. The original > was checking for a minimum of: > > if (index->map_size < sizeof(*header) + the_hash_algo->rawsz) > > which is the header plus the trailer. We want to readjust for the > MAX_RAWSZ part of the header, so it should be: > > size_t header_size = sizeof(*header) - GIT_MAX_RAWSZ + the_hash_algo->rawsz; > if (index->map_size < sizeof(*header) + the_hash_algo->rawsz) I'm not sure that I follow. If you apply this to the second patch in this series, the only thing that changes is that it factors out: index->map_pos += ...; into size_t header_size = ...; // ... index->map_pos += header_size; What am I missing here? Thanks, Taylor
