Re: pack corruption post-mortem

On Sat, Oct 19, 2013 at 9:41 PM, Nicolas Pitre [off-list ref] wrote:

On Sat, 19 Oct 2013, Duy Nguyen wrote:
The SHA1 used in the name of the pack file is actually the SHA1 checksum
of the SHA1 table.

The path and ident tables are already protected by the CRC32 in the zlib
deflated stream.

Normal objects are also zlib deflated (except for their header) but you
need to inflate them in order to have this CRC verified, which the pack
data copy tries to avoid.  Hence the separate CRC32 in the index file in
that case.

OK slight change in the subject, what about reading code (i.e.
sha1_file.c)? With v2 crc32 is verified by object inflate code. With
v4 trees or commits, because we store some (or all) data outside of
the deflated stream, we will not benefit from crc32 verifcation
previously done for all trees and commits. Should we perform explict
crc32 check when reading v4 trees and commits (and maybe verify the
sha-1 table too)?
-- 
Duy