From 18ee5a9d3779f5e8ee3142326dd65ae75b22bb0b Mon Sep 17 00:00:00 2001
From: ph10 <ph10@6239d852-aaf2-0410-a92c-79f79f948069>
Date: Mon, 22 Oct 2018 16:47:55 +0000
Subject: [PATCH] Fix heap limit checking overflow bug in pcre2_dfa_match().
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git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@1034 6239d852-aaf2-0410-a92c-79f79f948069

Petr Písař: Ported to 10.32.

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 src/pcre2_dfa_match.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/pcre2_dfa_match.c b/src/pcre2_dfa_match.c
index 9b43237..818004d 100644
--- a/src/pcre2_dfa_match.c
+++ b/src/pcre2_dfa_match.c
@@ -316,8 +316,8 @@ finding the minimum heap requirement for a match. */
 
 typedef struct RWS_anchor {
   struct RWS_anchor *next;
-  unsigned int size;  /* Number of ints */
-  unsigned int free;  /* Number of ints */
+  uint32_t size;  /* Number of ints */
+  uint32_t free;  /* Number of ints */
 } RWS_anchor;
 
 #define RWS_ANCHOR_SIZE (sizeof(RWS_anchor)/sizeof(int))
@@ -413,20 +413,24 @@ if (rws->next != NULL)
   new = rws->next;
   }
 
-/* All sizes are in units of sizeof(int), except for mb->heaplimit, which is in
-kibibytes. */
+/* Sizes in the RWS_anchor blocks are in units of sizeof(int), but
+mb->heap_limit and mb->heap_used are in kibibytes. Play carefully, to avoid
+overflow. */
 
 else
   {
-  unsigned int newsize = rws->size * 2;
-  unsigned int heapleft = (unsigned int)
-    (((1024/sizeof(int))*mb->heap_limit - mb->heap_used));
-  if (newsize > heapleft) newsize = heapleft;
+  uint32_t newsize = (rws->size >= UINT32_MAX/2)? UINT32_MAX/2 : rws->size * 2;
+  uint32_t newsizeK = newsize/(1024/sizeof(int));
+
+  if (newsizeK + mb->heap_used > mb->heap_limit)
+    newsizeK = mb->heap_limit - mb->heap_used;
+  newsize = newsizeK*(1024/sizeof(int));
+
   if (newsize < RWS_RSIZE + ovecsize + RWS_ANCHOR_SIZE)
     return PCRE2_ERROR_HEAPLIMIT;
   new = mb->memctl.malloc(newsize*sizeof(int), mb->memctl.memory_data);
   if (new == NULL) return PCRE2_ERROR_NOMEMORY;
-  mb->heap_used += newsize;
+  mb->heap_used += newsizeK;
   new->next = NULL;
   new->size = newsize;
   rws->next = new;
-- 
2.17.2