[PATCH 06/13] acl-permissions: use walloc

[Paul Eggert]

* lib/get-permissions.c: Include walloc.h.
(get_permissions): Use wreallocarray to fix possible integer overflow.
* lib/set-permissions.c: Include stdint.h, walloc.h.
(set_acls_from_mode): Use wgrowalloc instead of doing it by hand,
fixing a possible integer overflow.
* modules/acl-permissions (Depends-on): Add walloc.
---
 ChangeLog               |  8 ++++++++
 lib/get-permissions.c   |  7 +++++--
 lib/set-permissions.c   | 19 +++++++------------
 modules/acl-permissions |  1 +
 4 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ebd74b5..d4173d4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
 2017-06-04  Paul Eggert  <address@hidden>
 
+       acl-permissions: use walloc
+       * lib/get-permissions.c: Include walloc.h.
+       (get_permissions): Use wreallocarray to fix possible integer overflow.
+       * lib/set-permissions.c: Include stdint.h, walloc.h.
+       (set_acls_from_mode): Use wgrowalloc instead of doing it by hand,
+       fixing a possible integer overflow.
+       * modules/acl-permissions (Depends-on): Add walloc.
+
        dfa: use xwalloc instead of xalloc
        * NEWS: Mention dfa.
        * lib/dfa.c: Include xwalloc.h instead of xalloc.h, intprops.h.
diff --git a/lib/get-permissions.c b/lib/get-permissions.c
index dc77748..c8e1369 100644
--- a/lib/get-permissions.c
+++ b/lib/get-permissions.c
@@ -23,6 +23,7 @@
 #include "acl.h"
 
 #include "acl-internal.h"
+#include "walloc.h"
 
 /* Read the permissions of a file into CTX. If DESC is a valid file descriptor,
    use file descriptor operations, else use filename based operations on NAME.
@@ -130,7 +131,8 @@ get_permissions (const char *name, int desc, mode_t mode,
       if (ctx->ace_count == 0)
         break;
 
-      ctx->ace_entries = (ace_t *) malloc (ctx->ace_count * sizeof (ace_t));
+      ctx->ace_entries = (ace_t *) wreallocarray (NULL, ctx->ace_count,
+                                                  sizeof (ace_t));
       if (ctx->ace_entries == NULL)
         {
           errno = ENOMEM;
@@ -185,7 +187,8 @@ get_permissions (const char *name, int desc, mode_t mode,
       if (ctx->count == 0)
        break;
 
-      ctx->entries = (aclent_t *) malloc (ctx->count * sizeof (aclent_t));
+      ctx->entries = (aclent_t *) wreallocarray (NULL, ctx->count,
+                                                 sizeof (aclent_t));
       if (ctx->entries == NULL)
         {
           errno = ENOMEM;
diff --git a/lib/set-permissions.c b/lib/set-permissions.c
index 75bb2dc..14a28d0 100644
--- a/lib/set-permissions.c
+++ b/lib/set-permissions.c
@@ -21,7 +21,10 @@
 
 #include "acl.h"
 
+#include <stdint.h>
+
 #include "acl-internal.h"
+#include "walloc.h"
 
 #if USE_ACL
 # if ! defined HAVE_ACL_FROM_MODE && defined HAVE_ACL_FROM_TEXT /* FreeBSD, 
IRIX, Tru64 */
@@ -70,11 +73,7 @@ set_acls_from_mode (const char *name, int desc, mode_t mode, 
bool *must_chmod)
   {
     /* Initially, try to read the entries into a stack-allocated buffer.
        Use malloc if it does not fit.  */
-    enum
-      {
-        alloc_init = 4000 / sizeof (ace_t), /* >= 3 */
-        alloc_max = MIN (INT_MAX, SIZE_MAX / sizeof (ace_t))
-      };
+    enum { alloc_init = 4000 / sizeof (ace_t) }; /* >= 3 */
     ace_t buf[alloc_init];
     size_t alloc = alloc_init;
     ace_t *entries = buf;
@@ -90,13 +89,9 @@ set_acls_from_mode (const char *name, int desc, mode_t mode, 
bool *must_chmod)
           {
             /* Increase the size of the buffer.  */
             free (malloced);
-            if (alloc > alloc_max / 2)
-              {
-                errno = ENOMEM;
-                return -1;
-              }
-            alloc = 2 * alloc; /* <= alloc_max */
-            entries = malloced = (ace_t *) malloc (alloc * sizeof (ace_t));
+            entries = malloced = wgrowalloc (NULL, &alloc, 1,
+                                             MIN (INT_MAX, PTRDIFF_MAX),
+                                             sizeof *entries);
             if (entries == NULL)
               {
                 errno = ENOMEM;
diff --git a/modules/acl-permissions b/modules/acl-permissions
index 49b91ff..b043d3d 100644
--- a/modules/acl-permissions
+++ b/modules/acl-permissions
@@ -16,6 +16,7 @@ extern-inline
 fstat
 stdbool
 sys_stat
+walloc
 
 configure.ac:
 gl_FUNC_ACL
-- 
2.9.4