tree fd0ac67bb4033e954df59032c224e2cc1d7c2ffc
parent 0d38f1b26da2cfae07a0bf8347fe43dd2a2e942a
author Patrick Steinhardt <ps@pks.im> 1479206187 +0100
committer Edward Thomson <ethomson@github.com> 1483988720 -0500

smart_pkt: verify packet length exceeds PKT_LEN_SIZE

Each packet line in the Git protocol is prefixed by a four-byte
length of how much data will follow, which we parse in
`git_pkt_parse_line`. The transmitted length can either be equal
to zero in case of a flush packet or has to be at least of length
four, as it also includes the encoded length itself. Not
checking this may result in a buffer overflow as we directly pass
the length to functions which accept a `size_t` length as
parameter.

Fix the issue by verifying that non-flush packets have at least a
length of `PKT_LEN_SIZE`.