libgit2-sys affected by memory corruption, denial of service, and arbitrary code execution in libgit2

The libgit2 project fixed three security issues in the 1.7.2 release. These issues are:

• The git_revparse_single function can potentially enter an infinite loop on a well-crafted input, potentially causing a Denial of Service. This function is exposed in the git2 crate via the Repository::revparse_single method.
• The git_index_add function may cause heap corruption and possibly lead to arbitrary code execution. This function is exposed in the git2 crate via the Index::add method.
• The smart transport negotiation may experience an out-of-bounds read when a remote server did not advertise capabilities.

The libgit2-sys crate bundles libgit2, or optionally links to a system libgit2 library. In either case, versions of the libgit2 library less than 1.7.2 are vulnerable. The 0.16.2 release of libgit2-sys bundles the fixed version of 1.7.2, and requires a system libgit2 version of at least 1.7.2.

It is recommended that all users upgrade.