Attachment 72304 Details for Bug 58891 – [PATCH] Fix get_groups_for_user() for large number of users

[patch] [PATCH] Fix get_groups_for_user() for large number of users

07_get_groups_for_user_dynalloc.patch (text/plain), 2.41 KB, created by Michael Biebl on 2012-12-30 14:44:39 UTC

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Creator: Michael Biebl

Created: 2012-12-30 14:44:39 UTC

Size: 2.41 KB

patch

obsolete

>Description: Fix get_groups_for_user() for large number of users
> get_groups_for_user() used a hard-coded limit for the number of
> groups before, barring all access to users with a large number of
> groups.
> .
> Dynamically allocate the list instead, potentially resizing it based
> on what getgroupslist() tells us.
>Author: Sascha Silbe <sascha-pgp@silbe.org>
>
>---
>The information above should follow the Patch Tagging Guidelines, please
>checkout http://dep.debian.net/deps/dep3/ to learn about the format. Here
>are templates for supplementary fields that you might want to add:
>
>Bug-Debian: http://bugs.debian.org/696989
>Last-Update: 2012-12-30
>
>--- policykit-1-0.105.orig/src/polkitbackend/polkitbackendlocalauthority.c
>+++ policykit-1-0.105/src/polkitbackend/polkitbackendlocalauthority.c
>@@ -749,11 +749,17 @@ get_groups_for_user (PolkitIdentity *use
>   uid_t uid;
>   struct passwd *passwd;
>   GList *result;
>-  gid_t groups[512];
>-  int num_groups = 512;
>+  int num_groups, groups_size = 512;
>+  gid_t *groups = malloc(groups_size * sizeof(gid_t));
>   int n;
>+  int error;
> 
>   result = NULL;
>+  if (!groups)
>+  {
>+    g_warning ("Out of memory when looking up groups for uid %d", uid);
>+    goto out;
>+  }
> 
>   /* TODO: it would be, uhm, good to cache this information */
> 
>@@ -765,22 +771,34 @@ get_groups_for_user (PolkitIdentity *use
>       goto out;
>     }
> 
>-  /* TODO: should resize etc etc etc */
>-
>-  if (getgrouplist (passwd->pw_name,
>-                    passwd->pw_gid,
>-                    groups,
>-                    &num_groups) < 0)
>+  num_groups = groups_size;
>+  error = getgrouplist (passwd->pw_name, passwd->pw_gid, groups, &num_groups);
>+  if ((error < 0) && (num_groups > groups_size))
>+  {
>+    gid_t *new_groups;
>+
>+    groups_size = num_groups;
>+    new_groups = realloc(groups, groups_size * sizeof(gid_t));
>+    if (!new_groups)
>     {
>-      g_warning ("Error looking up groups for uid %d: %s", uid, g_strerror (errno));
>+      g_warning ("Out of memory when looking up groups for uid %d", uid);
>       goto out;
>     }
>+    groups = new_groups;
>+    error = getgrouplist (passwd->pw_name, passwd->pw_gid, groups, &num_groups);
>+  }
>+  if (error < 0)
>+  {
>+    g_warning ("Error looking up groups for uid %d: getgrouplist() failed", uid);
>+    goto out;
>+  }
> 
>   for (n = 0; n < num_groups; n++)
>     result = g_list_prepend (result, polkit_unix_group_new (groups[n]));
> 
>  out:
>-
>+  if (groups)
>+    free(groups);
>   return result;
> }
>

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