From 48050c42c73c28b0c001d63d11dffac7e116847b Mon Sep 17 00:00:00 2001 From: Patrick Steinhardt Date: Thu, 1 Dec 2022 15:46:49 +0100 Subject: pretty: fix integer overflow in wrapping format The `%w(width,indent1,indent2)` formatting directive can be used to rewrap text to a specific width and is designed after git-shortlog(1)'s `-w` parameter. While the three parameters are all stored as `size_t` internally, `strbuf_add_wrapped_text()` accepts integers as input. As a result, the casted integers may overflow. As these now-negative integers are later on passed to `strbuf_addchars()`, we will ultimately run into implementation-defined behaviour due to casting a negative number back to `size_t` again. On my platform, this results in trying to allocate 9000 petabyte of memory. Fix this overflow by using `cast_size_t_to_int()` so that we reject inputs that cannot be represented as an integer. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano --- git-compat-util.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'git-compat-util.h') diff --git a/git-compat-util.h b/git-compat-util.h index f505f817d5..0ac1b7f560 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -918,6 +918,14 @@ static inline size_t st_sub(size_t a, size_t b) return a - b; } +static inline int cast_size_t_to_int(size_t a) +{ + if (a > INT_MAX) + die("number too large to represent as int on this platform: %"PRIuMAX, + (uintmax_t)a); + return (int)a; +} + #ifdef HAVE_ALLOCA_H # include # define xalloca(size) (alloca(size)) -- cgit v1.2.3