Improve buffer-overflow checking (Bug#8873).

1 files changed, 26 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 59fb2d89b24..ae1a00cf173 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,29 @@
+2011-06-16  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Improve buffer-overflow checking (Bug#8873).
+        * fileio.c (Finsert_file_contents):
+        * insdel.c (insert_from_buffer_1, replace_range, replace_range_2):
+        Remove the old (too-loose) buffer overflow checks.
+        They weren't needed, since make_gap checks for buffer overflow.
+        * insdel.c (make_gap_larger): Catch buffer overflows that were missed.
+        The old code merely checked for Emacs fixnum overflow, and relied
+        on undefined (wraparound) behavior.  The new code avoids undefined
+        behavior, and also checks for ptrdiff_t and/or size_t overflow.
+
+        * editfns.c (Finsert_char): Don't dump core with very negative counts.
+        Tune.  Don't use wider integers than needed.  Don't use alloca.
+        Use a bigger 'string' buffer.  Rewrite to avoid 'n > 0' test.
+
+        * insdel.c (replace_range): Fix buf overflow when insbytes < outgoing.
+
+        * insdel.c, lisp.h (buffer_overflow): New function.
+        (insert_from_buffer_1, replace_range, replace_range_2):
+        * insdel.c (make_gap_larger):
+        * editfns.c (Finsert_char):
+        * fileio.c (Finsert_file_contents): Use it, to normalize wording.
+
+        * buffer.h (BUF_BYTES_MAX): Cast to ptrdiff_t so that it's signed.
+
 2011-06-15  Paul Eggert  <eggert@cs.ucla.edu>
 
         Integer overflow and signedness fixes (Bug#8873).