diff options
| author | Taylor Blau <me@ttaylorr.com> | 2021-03-05 18:21:56 +0300 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2021-03-05 22:33:52 +0300 |
| commit | 2a15964128edd08278efeacc75e75c77cfdde77e (patch) | |
| tree | fb84aacc8e8cf1b8a9e52f94931a20bde949d079 /builtin/repack.c | |
| parent | 13d746a303592068826824b30c47941fb328c8a7 (diff) | |
builtin/repack.c: be more conservative with unsigned overflows
There are a number of places in the geometric repack code where we
multiply the number of objects in a pack by another unsigned value. We
trust that the number of objects in a pack is always representable by a
uint32_t, but we don't necessarily trust that that number can be
multiplied without overflow.
Sprinkle some unsigned_add_overflows() and unsigned_mult_overflows() in
split_pack_geometry() to check that we never overflow any unsigned types
when adding or multiplying them.
Arguably these checks are a little too conservative, and certainly they
do not help the readability of this function. But they are serving a
useful purpose, so I think they are worthwhile overall.
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'builtin/repack.c')
| -rw-r--r-- | builtin/repack.c | 24 |
1 files changed, 22 insertions, 2 deletions
diff --git a/builtin/repack.c b/builtin/repack.c index 21a5778e73..677c6b75c1 100644 --- a/builtin/repack.c +++ b/builtin/repack.c @@ -363,6 +363,12 @@ static void split_pack_geometry(struct pack_geometry *geometry, int factor) for (i = geometry->pack_nr - 1; i > 0; i--) { struct packed_git *ours = geometry->pack[i]; struct packed_git *prev = geometry->pack[i - 1]; + + if (unsigned_mult_overflows(factor, geometry_pack_weight(prev))) + die(_("pack %s too large to consider in geometric " + "progression"), + prev->pack_name); + if (geometry_pack_weight(ours) < factor * geometry_pack_weight(prev)) break; } @@ -388,11 +394,25 @@ static void split_pack_geometry(struct pack_geometry *geometry, int factor) * packs in the heavy half need to be joined into it (if any) to restore * the geometric progression. */ - for (i = 0; i < split; i++) - total_size += geometry_pack_weight(geometry->pack[i]); + for (i = 0; i < split; i++) { + struct packed_git *p = geometry->pack[i]; + + if (unsigned_add_overflows(total_size, geometry_pack_weight(p))) + die(_("pack %s too large to roll up"), p->pack_name); + total_size += geometry_pack_weight(p); + } for (i = split; i < geometry->pack_nr; i++) { struct packed_git *ours = geometry->pack[i]; + + if (unsigned_mult_overflows(factor, total_size)) + die(_("pack %s too large to roll up"), ours->pack_name); + if (geometry_pack_weight(ours) < factor * total_size) { + if (unsigned_add_overflows(total_size, + geometry_pack_weight(ours))) + die(_("pack %s too large to roll up"), + ours->pack_name); + split++; total_size += geometry_pack_weight(ours); } else |