2 files changed, 7 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 6cf45e5d2aa..1e9cf82d1ac 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -13,6 +13,7 @@
         (substitute_object_recurse, read_vector, read_list, map_obarray):
         Use ptrdiff_t, not int, for sizes.
         (read1): Use EMACS_INT, not int, for sizes.
+        Check for size overflow.
 
         * image.c (cache_image): Check for size arithmetic overflow.
 
diff --git a/src/lread.c b/src/lread.c
index 18569df554b..06b957cf392 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -2869,6 +2869,8 @@ read1 (register Lisp_Object readcharfun, int *pch, int first_in_list)
             if (end - p < MAX_MULTIBYTE_LENGTH)
               {
                 ptrdiff_t offset = p - read_buffer;
+                if (min (PTRDIFF_MAX, SIZE_MAX) / 2 < read_buffer_size)
+                  memory_full (SIZE_MAX);
                 read_buffer = (char *) xrealloc (read_buffer,
                                                  read_buffer_size *= 2);
                 p = read_buffer + offset;
@@ -3012,6 +3014,8 @@ read1 (register Lisp_Object readcharfun, int *pch, int first_in_list)
               if (end - p < MAX_MULTIBYTE_LENGTH)
                 {
                   ptrdiff_t offset = p - read_buffer;
+                  if (min (PTRDIFF_MAX, SIZE_MAX) / 2 < read_buffer_size)
+                    memory_full (SIZE_MAX);
                   read_buffer = (char *) xrealloc (read_buffer,
                                                    read_buffer_size *= 2);
                   p = read_buffer + offset;
@@ -3039,6 +3043,8 @@ read1 (register Lisp_Object readcharfun, int *pch, int first_in_list)
           if (p == end)
             {
               ptrdiff_t offset = p - read_buffer;
+              if (min (PTRDIFF_MAX, SIZE_MAX) / 2 < read_buffer_size)
+                memory_full (SIZE_MAX);
               read_buffer = (char *) xrealloc (read_buffer,
                                                read_buffer_size *= 2);
               p = read_buffer + offset;