[PATCH 0/2] tree-walk: use size_t for tree sizes

[Elia Pinto <gitter.spiros@gmail.com>]

struct tree_desc keeps the size of the tree buffer in an "unsigned
int", so a tree object of 4GiB or more is truncated on all platforms,
and struct tree adds another truncation on Windows, where "long" is
32 bits. The walk then sees only a prefix of the tree: it never reads
past the buffer, but when the cut falls between two entries the rest
of the tree silently disappears, both for commands like "git ls-tree"
and for the checks in fsck_tree().

Trees that large are not something one creates by accident, but they
can be crafted, and fsck is what is supposed to look at every entry
of them.

 1/2 moves struct tree_desc and the functions that set it up to
     size_t; this is the part that matters on all platforms.
 2/2 does the same for struct tree and parse_tree_buffer().

There is no test, as it would need a tree larger than 4GiB in memory;
1/2 describes how I checked the effect with a simulated 16-bit size.

This comes from the same search for truncated sizes as:

  https://lore.kernel.org/git/cover.1793352943.git.gitter.spiros@gmail.com/
  https://lore.kernel.org/git/cover.1793355390.git.gitter.spiros@gmail.com/

It is independent of both and merges cleanly with them. The series is
based on master (b9e5cff180).

Elia Pinto (2):
  tree-walk: use size_t for the size of tree buffers
  tree: use size_t for the size of parsed trees

 tree-walk.c | 14 +++++++-------
 tree-walk.h |  6 +++---
 tree.c      |  2 +-
 tree.h      |  4 ++--
 4 files changed, 13 insertions(+), 13 deletions(-)


base-commit: b9e5cff1803ab24582201ef059516eb16014b9d9
-- 
2.53.0