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bug#9079: integer overflow etc. issues (e.g., image crashes Emacs)
From: |
Paul Eggert |
Subject: |
bug#9079: integer overflow etc. issues (e.g., image crashes Emacs) |
Date: |
Thu, 14 Jul 2011 15:02:06 -0700 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.18) Gecko/20110621 Fedora/3.1.11-1.fc14 Thunderbird/3.1.11 |
OK, here's an updated version of the bidi.c part of that patch,
reflecting the bidi changes just made to the trunk.
* bidi.c: Integer size and overflow fixes.
(bidi_cache_size, bidi_cache_idx, bidi_cache_last_idx)
(bidi_cache_start, bidi_cache_fetch_state, bidi_cache_search)
(bidi_cache_find_level_change, bidi_cache_ensure_space)
(bidi_cache_iterator_state, bidi_cache_find, bidi_cache_start_stack)
(bidi_find_other_level_edge):
Use ptrdiff_t instead of EMACS_INT where either will do.
This works better on 32-bit hosts configured --with-wide-int.
(bidi_cache_ensure_space): Check for size-calculation overflow.
Use % rather than repeated addition, for better worst-case speed.
Don't set bidi_cache_size until after xrealloc returns, because it
might not return.
(bidi_dump_cached_states): Use ptrdiff_t, not int, to avoid overflow.
=== modified file 'src/bidi.c'
--- src/bidi.c 2011-07-14 21:46:32 +0000
+++ src/bidi.c 2011-07-14 21:46:40 +0000
@@ -299,11 +299,11 @@
#define BIDI_CACHE_CHUNK 200
static struct bidi_it *bidi_cache;
-static EMACS_INT bidi_cache_size = 0;
+static ptrdiff_t bidi_cache_size = 0;
enum { elsz = sizeof (struct bidi_it) };
-static EMACS_INT bidi_cache_idx; /* next unused cache slot */
-static EMACS_INT bidi_cache_last_idx; /* slot of last cache hit */
-static EMACS_INT bidi_cache_start = 0; /* start of cache for this
+static ptrdiff_t bidi_cache_idx; /* next unused cache slot */
+static ptrdiff_t bidi_cache_last_idx; /* slot of last cache hit */
+static ptrdiff_t bidi_cache_start = 0; /* start of cache for this
"stack" level */
/* Reset the cache state to the empty state. We only reset the part
@@ -336,7 +336,7 @@
}
static inline void
-bidi_cache_fetch_state (EMACS_INT idx, struct bidi_it *bidi_it)
+bidi_cache_fetch_state (ptrdiff_t idx, struct bidi_it *bidi_it)
{
int current_scan_dir = bidi_it->scan_dir;
@@ -352,10 +352,10 @@
level less or equal to LEVEL. if LEVEL is -1, disregard the
resolved levels in cached states. DIR, if non-zero, means search
in that direction from the last cache hit. */
-static inline EMACS_INT
+static inline ptrdiff_t
bidi_cache_search (EMACS_INT charpos, int level, int dir)
{
- EMACS_INT i, i_start;
+ ptrdiff_t i, i_start;
if (bidi_cache_idx > bidi_cache_start)
{
@@ -417,12 +417,12 @@
C, searching backwards (DIR = -1) for LEVEL = 2 will return the
index of slot B or A, depending whether BEFORE is, respectively,
non-zero or zero. */
-static EMACS_INT
+static ptrdiff_t
bidi_cache_find_level_change (int level, int dir, int before)
{
if (bidi_cache_idx)
{
- EMACS_INT i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1;
+ ptrdiff_t i = dir ? bidi_cache_last_idx : bidi_cache_idx - 1;
int incr = before ? 1 : 0;
xassert (!dir || bidi_cache_last_idx >= 0);
@@ -458,22 +458,26 @@
}
static inline void
-bidi_cache_ensure_space (EMACS_INT idx)
+bidi_cache_ensure_space (ptrdiff_t idx)
{
/* Enlarge the cache as needed. */
if (idx >= bidi_cache_size)
{
- while (idx >= bidi_cache_size)
- bidi_cache_size += BIDI_CACHE_CHUNK;
- bidi_cache =
- (struct bidi_it *) xrealloc (bidi_cache, bidi_cache_size * elsz);
+ ptrdiff_t new_size;
+ ptrdiff_t max_size =
+ min (PTRDIFF_MAX, SIZE_MAX) / elsz / BIDI_CACHE_CHUNK *
BIDI_CACHE_CHUNK;
+ if (max_size <= idx)
+ memory_full (SIZE_MAX);
+ new_size = idx - idx % BIDI_CACHE_CHUNK + BIDI_CACHE_CHUNK;
+ bidi_cache = (struct bidi_it *) xrealloc (bidi_cache, new_size * elsz);
+ bidi_cache_size = new_size;
}
}
static inline void
bidi_cache_iterator_state (struct bidi_it *bidi_it, int resolved)
{
- EMACS_INT idx;
+ ptrdiff_t idx;
/* We should never cache on backward scans. */
if (bidi_it->scan_dir == -1)
@@ -528,7 +532,7 @@
static inline bidi_type_t
bidi_cache_find (EMACS_INT charpos, int level, struct bidi_it *bidi_it)
{
- EMACS_INT i = bidi_cache_search (charpos, level, bidi_it->scan_dir);
+ ptrdiff_t i = bidi_cache_search (charpos, level, bidi_it->scan_dir);
if (i >= bidi_cache_start)
{
@@ -560,7 +564,7 @@
/* 5-slot stack for saving the start of the previous level of the
cache. xdisp.c maintains a 5-slot stack for its iterator state,
and we need the same size of our stack. */
-static EMACS_INT bidi_cache_start_stack[IT_STACK_SIZE];
+static ptrdiff_t bidi_cache_start_stack[IT_STACK_SIZE];
static int bidi_cache_sp;
/* Push the bidi iterator state in preparation for reordering a
@@ -2123,7 +2127,7 @@
bidi_find_other_level_edge (struct bidi_it *bidi_it, int level, int end_flag)
{
int dir = end_flag ? -bidi_it->scan_dir : bidi_it->scan_dir;
- EMACS_INT idx;
+ ptrdiff_t idx;
/* Try the cache first. */
if ((idx = bidi_cache_find_level_change (level, dir, end_flag))
@@ -2300,7 +2304,7 @@
void
bidi_dump_cached_states (void)
{
- int i;
+ ptrdiff_t i;
int ndigits = 1;
if (bidi_cache_idx == 0)