From: Junio C Hamano <gitster@pobox.com>
Date: Sat, 29 Mar 2025 07:39:10 +0000 (+0900)
Subject: Merge branch 'rs/xdiff-context-length-fix'
X-Git-Tag: v2.50.0-rc0~160
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6767149eca352db846ae065fa67614a1b4bc45a6;p=thirdparty%2Fgit.git

Merge branch 'rs/xdiff-context-length-fix'

The xdiff code on 32-bit platform misbehaved when an insanely large
context size is given, which has been corrected.

* rs/xdiff-context-length-fix:
  xdiff: avoid arithmetic overflow in xdl_get_hunk()
---

6767149eca352db846ae065fa67614a1b4bc45a6
diff --cc xdiff/xemit.c
index f8e3f25b03,6fc05fc3f3..1d40c9cb40
--- a/xdiff/xemit.c
+++ b/xdiff/xemit.c
@@@ -52,9 -56,11 +56,11 @@@ static long saturating_add(long a, lon
  xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
  {
  	xdchange_t *xch, *xchp, *lxch;
- 	long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
+ 	long max_common = saturating_add(saturating_add(xecfg->ctxlen,
+ 							xecfg->ctxlen),
+ 					 xecfg->interhunkctxlen);
  	long max_ignorable = xecfg->ctxlen;
 -	unsigned long ignored = 0; /* number of ignored blank lines */
 +	long ignored = 0; /* number of ignored blank lines */
  
  	/* remove ignorable changes that are too far before other changes */
  	for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {