From 8f282bdff0b49744b45d619075b59a5e8b596613 Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Thu, 17 Apr 2025 12:49:36 +0200 Subject: [PATCH] parse: fix off-by-one for minimum signed values We accept a maximum value in `git_parse_signed()` that restricts the range of accepted integers. As the intent is to pass `INT*_MAX` values here, this maximum doesn't only act as the upper bound, but also as the implicit lower bound of the accepted range. This lower bound is calculated by negating the maximum. But given that the maximum value of a signed integer with N bits is `2^(N-1)-1` whereas the minimum value is `-2^(N-1)` we have an off-by-one error in the lower bound. Fix this off-by-one error by using `-max - 1` as lower bound instead. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- parse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/parse.c b/parse.c index 7a60a4f816..3c47448ca6 100644 --- a/parse.c +++ b/parse.c @@ -38,7 +38,7 @@ int git_parse_signed(const char *value, intmax_t *ret, intmax_t max) errno = EINVAL; return 0; } - if ((val < 0 && -max / factor > val) || + if ((val < 0 && (-max - 1) / factor > val) || (val > 0 && max / factor < val)) { errno = ERANGE; return 0; -- 2.47.2