Avoid integer overflows around realloc calls resulting in potential

heap. Problem identified by Guido Vranken. Changes differ from original
OpenBSD sources by not depending on non-portable reallocarray.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228507 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Support/regcomp.c b/lib/Support/regcomp.c
index 0b5b765f89e14556554761e6df78916b2ff8fa91..b79692966473dd474307c70f2210bb57f70d77ca 100644 (file)
--- a/lib/Support/regcomp.c
+++ b/lib/Support/regcomp.c
@@ -49,6 +49,14 @@
 #include "regcclass.h"
 #include "regcname.h"
 
+#include "llvm/Config/config.h"
+#if HAVE_STDINT_H
+#include <stdint.h>
+#else
+/* Pessimistically bound memory use */
+#define SIZE_MAX UINT_MAX
+#endif
+
 /*
  * parse structure, passed up and down to avoid global variables and
  * other clumsinesses
@@ -1069,6 +1077,8 @@ allocset(struct parse *p)
 
                p->ncsalloc += CHAR_BIT;
                nc = p->ncsalloc;
+               if (nc > SIZE_MAX / sizeof(cset))
+                       goto nomem;
                assert(nc % CHAR_BIT == 0);
                nbytes = nc / CHAR_BIT * css;
 
@@ -1412,6 +1422,11 @@ enlarge(struct parse *p, sopno size)
        if (p->ssize >= size)
                return;
 
+       if ((unsigned long)size > SIZE_MAX / sizeof(sop)) {
+               SETERROR(REG_ESPACE);
+               return;
+       }
+
        sp = (sop *)realloc(p->strip, size*sizeof(sop));
        if (sp == NULL) {
                SETERROR(REG_ESPACE);
@@ -1428,6 +1443,12 @@ static void
 stripsnug(struct parse *p, struct re_guts *g)
 {
        g->nstates = p->slen;
+       if ((unsigned long)p->slen > SIZE_MAX / sizeof(sop)) {
+               g->strip = p->strip;
+               SETERROR(REG_ESPACE);
+               return;
+       }
+
        g->strip = (sop *)realloc((char *)p->strip, p->slen * sizeof(sop));
        if (g->strip == NULL) {
                SETERROR(REG_ESPACE);