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authorSiddhesh Poyarekar <siddhesh@sourceware.org>2020-12-23 07:41:17 +0530
committerSiddhesh Poyarekar <siddhesh@sourceware.org>2020-12-24 06:02:05 +0530
commit84c202246b74c2f75b36985ceff506b7a152c2fb (patch)
tree4b6f6ddedc5570b7636001fa6fade0883c93e793
parent4f969166ce4ab535fa798dcbaa5de4c4e05773ec (diff)
downloadglibc-84c202246b74c2f75b36985ceff506b7a152c2fb.tar.gz
glibc-84c202246b74c2f75b36985ceff506b7a152c2fb.tar.xz
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MTE: Do not pad size in realloc_check
The MTE patch to add malloc support incorrectly padded the size passed
to _int_realloc by SIZE_SZ when it ought to have sent just the
chunksize.  Revert that bit of the change so that realloc works
correctly with MALLOC_CHECK_ set.

This also brings the realloc_check implementation back in sync with
libc_realloc.
-rw-r--r--malloc/hooks.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/malloc/hooks.c b/malloc/hooks.c
index 8a1c16dfa4..6474ba8b38 100644
--- a/malloc/hooks.c
+++ b/malloc/hooks.c
@@ -315,7 +315,7 @@ realloc_check (void *oldmem, size_t bytes, const void *caller)
   __libc_lock_unlock (main_arena.mutex);
   if (!oldp)
     malloc_printerr ("realloc(): invalid pointer");
-  const INTERNAL_SIZE_T oldchsize = CHUNK_AVAILABLE_SIZE (oldp);
+  const INTERNAL_SIZE_T oldsize = chunksize (oldp);
 
   if (!checked_request2size (rb, &chnb))
     goto invert;
@@ -331,7 +331,8 @@ realloc_check (void *oldmem, size_t bytes, const void *caller)
       else
 #endif
       {
-        if (oldchsize >= chnb)
+	/* Note the extra SIZE_SZ overhead. */
+        if (oldsize - SIZE_SZ >= chnb)
           newmem = oldmem; /* do nothing */
         else
           {
@@ -340,7 +341,7 @@ realloc_check (void *oldmem, size_t bytes, const void *caller)
 	    newmem = _int_malloc (&main_arena, rb);
             if (newmem)
               {
-                memcpy (newmem, oldmem, oldchsize - CHUNK_HDR_SZ);
+                memcpy (newmem, oldmem, oldsize - CHUNK_HDR_SZ);
                 munmap_chunk (oldp);
               }
           }
@@ -349,7 +350,7 @@ realloc_check (void *oldmem, size_t bytes, const void *caller)
   else
     {
       top_check ();
-      newmem = _int_realloc (&main_arena, oldp, oldchsize, chnb);
+      newmem = _int_realloc (&main_arena, oldp, oldsize, chnb);
     }
 
   DIAG_PUSH_NEEDS_COMMENT;