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delta-apply: fix sign extension

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We compute offsets by executing `off |= (*delta++ << 24)` for
multiple constants, where `off` is of type `size_t` and `delta`
is of type `unsigned char`. The usual arithmetic conversions (see
ISO C89 §3.2.1.5 "Usual arithmetic conversions") kick in here,
causing us to promote both operands to `int` and then extending
the result to an `unsigned long` when OR'ing it with `off`.
The integer promotion to `int` may result in wrong size
calculations for big values.

Fix the issue by making the constants `unsigned long`, causing both
operands to be promoted to `unsigned long`.
This commit is contained in:
Patrick Steinhardt 2016-05-02 16:49:59 +02:00 committed by Carlos Martín Nieto
parent 1fb8a951b6
commit cf0396a563
1 changed files with 5 additions and 5 deletions
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10
src/delta-apply.c
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@ -121,13 +121,13 @@ int git__delta_apply(
size_t off = 0, len = 0; size_t off = 0, len = 0;
if (cmd & 0x01) off = *delta++; if (cmd & 0x01) off = *delta++;
if (cmd & 0x02) off |= *delta++ << 8; if (cmd & 0x02) off |= *delta++ << 8UL;
if (cmd & 0x04) off |= *delta++ << 16; if (cmd & 0x04) off |= *delta++ << 16UL;
if (cmd & 0x08) off |= *delta++ << 24; if (cmd & 0x08) off |= *delta++ << 24UL;
if (cmd & 0x10) len = *delta++; if (cmd & 0x10) len = *delta++;
if (cmd & 0x20) len |= *delta++ << 8; if (cmd & 0x20) len |= *delta++ << 8UL;
if (cmd & 0x40) len |= *delta++ << 16; if (cmd & 0x40) len |= *delta++ << 16UL;
if (!len) len = 0x10000; if (!len) len = 0x10000;
if (base_len < off + len || res_sz < len) if (base_len < off + len || res_sz < len)