Let realloc handle and produce moved pointers for allocations betweenlibressl-v2.5.1

half a page and a page. ok jmatthew@ tb@

1 files changed, 37 insertions, 20 deletions

diff --git a/src/lib/libc/stdlib/malloc.c b/src/lib/libc/stdlib/malloc.c
index 30cfd48986..9861f6d153 100644
--- a/src/lib/libc/stdlib/malloc.c
+++ b/src/lib/libc/stdlib/malloc.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: malloc.c,v 1.212 2017/01/21 07:47:42 otto Exp $       */
+/*      $OpenBSD: malloc.c,v 1.213 2017/02/01 06:17:42 otto Exp $       */
 /*
  * Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net>
  * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org>
@@ -1328,13 +1328,9 @@ ofree(struct dir_info *argpool, void *p)
                                     sz - mopts.malloc_guard,
                                     PAGEROUND(sz - mopts.malloc_guard));
                 } else {
-#if notyetbecause_of_realloc
                         /* shifted towards the end */
-                        if (p != ((char *)r->p) + ((MALLOC_PAGESIZE -
-                            MALLOC_MINSIZE - sz - mopts.malloc_guard) &
-                            ~(MALLOC_MINSIZE-1))) {
-                        }
-#endif
+                        if (p != MALLOC_MOVE(r->p, sz))
+                                wrterror(pool, "bogus moved pointer %p", p);
                         p = r->p;
                 }
                 if (mopts.malloc_guard) {
@@ -1474,7 +1470,7 @@ orealloc(struct dir_info *argpool, void *p, size_t newsz, void *f)
         if (gnewsz > MALLOC_MAXCHUNK)
                 gnewsz += mopts.malloc_guard;
 
-        if (newsz > MALLOC_MAXCHUNK && oldsz > MALLOC_MAXCHUNK && p == r->p &&
+        if (newsz > MALLOC_MAXCHUNK && oldsz > MALLOC_MAXCHUNK &&
             !mopts.malloc_realloc) {
                 /* First case: from n pages sized allocation to m pages sized
                    allocation, no malloc_move in effect */
@@ -1484,7 +1480,7 @@ orealloc(struct dir_info *argpool, void *p, size_t newsz, void *f)
                 if (rnewsz > roldsz) {
                         /* try to extend existing region */
                         if (!mopts.malloc_guard) {
-                                void *hint = (char *)p + roldsz;
+                                void *hint = (char *)r->p + roldsz;
                                 size_t needed = rnewsz - roldsz;
 
                                 STATS_INC(pool->cheap_realloc_tries);
@@ -1502,9 +1498,15 @@ gotit:
                                         STATS_ADD(pool->malloc_used, needed);
                                         if (mopts.malloc_junk == 2)
                                                 memset(q, SOME_JUNK, needed);
-                                        r->size = newsz;
+                                        r->size = gnewsz;
+                                        if (r->p != p) {
+                                                /* old pointer is moved */
+                                                memmove(r->p, p, oldsz);
+                                                p = r->p;
+                                        }
                                         if (mopts.chunk_canaries)
-                                                fill_canary(p, newsz, PAGEROUND(newsz));
+                                                fill_canary(p, newsz,
+                                                    PAGEROUND(newsz));
                                         STATS_SETF(r, f);
                                         STATS_INC(pool->cheap_reallocs);
                                         ret = p;
@@ -1517,30 +1519,45 @@ gotit:
                 } else if (rnewsz < roldsz) {
                         /* shrink number of pages */
                         if (mopts.malloc_guard) {
-                                if (mprotect((char *)p + roldsz -
+                                if (mprotect((char *)r->p + roldsz -
                                     mopts.malloc_guard, mopts.malloc_guard,
                                     PROT_READ | PROT_WRITE))
                                         wrterror(pool, "mprotect");
-                                if (mprotect((char *)p + rnewsz -
+                                if (mprotect((char *)r->p + rnewsz -
                                     mopts.malloc_guard, mopts.malloc_guard,
                                     PROT_NONE))
                                         wrterror(pool, "mprotect");
                         }
-                        unmap(pool, (char *)p + rnewsz, roldsz - rnewsz);
+                        unmap(pool, (char *)r->p + rnewsz, roldsz - rnewsz);
                         r->size = gnewsz;
-                        if (mopts.chunk_canaries)
+                        if (MALLOC_MOVE_COND(gnewsz)) {
+                                void *pp = MALLOC_MOVE(r->p, gnewsz);
+                                memmove(pp, p, newsz);
+                                p = pp;
+                        } else if (mopts.chunk_canaries)
                                 fill_canary(p, newsz, PAGEROUND(newsz));
                         STATS_SETF(r, f);
                         ret = p;
                         goto done;
                 } else {
                         /* number of pages remains the same */
-                        if (newsz > oldsz && mopts.malloc_junk == 2)
-                                memset((char *)p + newsz, SOME_JUNK,
-                                    rnewsz - mopts.malloc_guard - newsz);
+                        void *pp = r->p;
+
                         r->size = gnewsz;
-                        if (mopts.chunk_canaries)
-                                fill_canary(p, newsz, PAGEROUND(newsz));
+                        if (MALLOC_MOVE_COND(gnewsz))
+                                pp = MALLOC_MOVE(r->p, gnewsz);
+                        if (p != pp) {
+                                memmove(pp, p, oldsz < newsz ? oldsz : newsz);
+                                p = pp;
+                        }
+                        if (p == r->p) {
+                                if (newsz > oldsz && mopts.malloc_junk == 2)
+                                        memset((char *)p + newsz, SOME_JUNK,
+                                            rnewsz - mopts.malloc_guard -
+                                            newsz);
+                                if (mopts.chunk_canaries)
+                                        fill_canary(p, newsz, PAGEROUND(newsz));
+                        }
                         STATS_SETF(r, f);
                         ret = p;
                         goto done;