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Description: Disallow an excessively large pattern space
Apply heap overflow vulnerability patch to bundled regex library.
Unfortunately nvi uses the BSD-specific REG_NOSPEC flag, so we can't easily
switch to the system library.
Origin: vendor, https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/2841837793bd095a82f477e9c370cfe6cfb3862c
Bug-Debian: https://bugs.debian.org/778412
Forwarded: no
Last-Update: 2016-12-31
Index: b/regex/regcomp.c
===================================================================
--- a/regex/regcomp.c
+++ b/regex/regcomp.c
@@ -183,6 +183,7 @@
register struct parse *p = &pa;
register int i;
register size_t len;
+ size_t maxlen;
#ifdef REDEBUG
# define GOODFLAGS(f) (f)
#else
@@ -205,7 +206,23 @@
(NC-1)*sizeof(cat_t));
if (g == NULL)
return(REG_ESPACE);
+ /*
+ * Limit the pattern space to avoid a 32-bit overflow on buffer
+ * extension. Also avoid any signed overflow in case of conversion
+ * so make the real limit based on a 31-bit overflow.
+ *
+ * Likely not applicable on 64-bit systems but handle the case
+ * generically (who are we to stop people from using ~715MB+
+ * patterns?).
+ */
+ maxlen = ((size_t)-1 >> 1) / sizeof(sop) * 2 / 3;
+ if (len >= maxlen) {
+ free((char *)g);
+ return(REG_ESPACE);
+ }
p->ssize = len/(size_t)2*(size_t)3 + (size_t)1; /* ugh */
+ assert(p->ssize >= len);
+
p->strip = (sop *)malloc(p->ssize * sizeof(sop));
p->slen = 0;
if (p->strip == NULL) {
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