From 86d2169ac3458412a084c7fc4047c3a389924cad Mon Sep 17 00:00:00 2001 From: Eli Zaretskii Date: Thu, 4 Oct 2018 19:13:17 +0300 Subject: [PATCH] Avoid ridiculously high stack limit requests on macOS * src/emacs.c (main): Avoid wraparound in subtraction of rlim_t values, in case rlim_t is an unsigned type. (Bug#32338) --- src/emacs.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/src/emacs.c b/src/emacs.c index 483e848f6db..f80047e89e7 100644 --- a/src/emacs.c +++ b/src/emacs.c @@ -875,7 +875,8 @@ main (int argc, char **argv) newlim = rlim.rlim_max; newlim -= newlim % pagesize; - if (pagesize <= newlim - lim) + if (newlim > lim /* in case rlim_t is an unsigned type */ + && pagesize <= newlim - lim) { rlim.rlim_cur = newlim; if (setrlimit (RLIMIT_STACK, &rlim) == 0) @@ -884,9 +885,10 @@ main (int argc, char **argv) } /* If the stack is big enough, let regex.c more of it before falling back to heap allocation. */ - emacs_re_safe_alloca = max - (min (lim - extra, SIZE_MAX) * (min_ratio / ratio), - MAX_ALLOCA); + if (lim < extra) + lim = extra; /* avoid wrap-around in unsigned subtraction */ + emacs_re_safe_alloca = + max (min (lim - extra, SIZE_MAX) * (min_ratio / ratio), MAX_ALLOCA); } #endif /* HAVE_SETRLIMIT and RLIMIT_STACK and not CYGWIN */ -- 2.39.5