cred: simpler, 1D supplementary groups

[cascardo/linux.git] / kernel / groups.c

diff --git a/kernel/groups.c b/kernel/groups.c
index 74d431d..2fcadd6 100644 (file)
--- a/kernel/groups.c
+++ b/kernel/groups.c
@@ -7,55 +7,31 @@
 #include <linux/security.h>
 #include <linux/syscalls.h>
 #include <linux/user_namespace.h>
+#include <linux/vmalloc.h>
 #include <asm/uaccess.h>
 
 struct group_info *groups_alloc(int gidsetsize)
 {
-       struct group_info *group_info;
-       int nblocks;
-       int i;
-
-       nblocks = (gidsetsize + NGROUPS_PER_BLOCK - 1) / NGROUPS_PER_BLOCK;
-       /* Make sure we always allocate at least one indirect block pointer */
-       nblocks = nblocks ? : 1;
-       group_info = kmalloc(sizeof(*group_info) + nblocks*sizeof(gid_t *), GFP_USER);
-       if (!group_info)
+       struct group_info *gi;
+       unsigned int len;
+
+       len = sizeof(struct group_info) + sizeof(kgid_t) * gidsetsize;
+       gi = kmalloc(len, GFP_KERNEL_ACCOUNT|__GFP_NOWARN|__GFP_NORETRY);
+       if (!gi)
+               gi = __vmalloc(len, GFP_KERNEL_ACCOUNT|__GFP_HIGHMEM, PAGE_KERNEL);
+       if (!gi)
                return NULL;
-       group_info->ngroups = gidsetsize;
-       group_info->nblocks = nblocks;
-       atomic_set(&group_info->usage, 1);
-
-       if (gidsetsize <= NGROUPS_SMALL)
-               group_info->blocks[0] = group_info->small_block;
-       else {
-               for (i = 0; i < nblocks; i++) {
-                       kgid_t *b;
-                       b = (void *)__get_free_page(GFP_USER);
-                       if (!b)
-                               goto out_undo_partial_alloc;
-                       group_info->blocks[i] = b;
-               }
-       }
-       return group_info;
 
-out_undo_partial_alloc:
-       while (--i >= 0) {
-               free_page((unsigned long)group_info->blocks[i]);
-       }
-       kfree(group_info);
-       return NULL;
+       atomic_set(&gi->usage, 1);
+       gi->ngroups = gidsetsize;
+       return gi;
 }
 
 EXPORT_SYMBOL(groups_alloc);
 
 void groups_free(struct group_info *group_info)
 {
-       if (group_info->blocks[0] != group_info->small_block) {
-               int i;
-               for (i = 0; i < group_info->nblocks; i++)
-                       free_page((unsigned long)group_info->blocks[i]);
-       }
-       kfree(group_info);
+       kvfree(group_info);
 }
 
 EXPORT_SYMBOL(groups_free);
@@ -70,7 +46,7 @@ static int groups_to_user(gid_t __user *grouplist,
 
        for (i = 0; i < count; i++) {
                gid_t gid;
-               gid = from_kgid_munged(user_ns, GROUP_AT(group_info, i));
+               gid = from_kgid_munged(user_ns, group_info->gid[i]);
                if (put_user(gid, grouplist+i))
                        return -EFAULT;
        }
@@ -95,7 +71,7 @@ static int groups_from_user(struct group_info *group_info,
                if (!gid_valid(kgid))
                        return -EINVAL;
 
-               GROUP_AT(group_info, i) = kgid;
+               group_info->gid[i] = kgid;
        }
        return 0;
 }
@@ -115,15 +91,14 @@ static void groups_sort(struct group_info *group_info)
                for (base = 0; base < max; base++) {
                        int left = base;
                        int right = left + stride;
-                       kgid_t tmp = GROUP_AT(group_info, right);
+                       kgid_t tmp = group_info->gid[right];
 
-                       while (left >= 0 && gid_gt(GROUP_AT(group_info, left), tmp)) {
-                               GROUP_AT(group_info, right) =
-                                   GROUP_AT(group_info, left);
+                       while (left >= 0 && gid_gt(group_info->gid[left], tmp)) {
+                               group_info->gid[right] = group_info->gid[left];
                                right = left;
                                left -= stride;
                        }
-                       GROUP_AT(group_info, right) = tmp;
+                       group_info->gid[right] = tmp;
                }
                stride /= 3;
        }
@@ -141,9 +116,9 @@ int groups_search(const struct group_info *group_info, kgid_t grp)
        right = group_info->ngroups;
        while (left < right) {
                unsigned int mid = (left+right)/2;
-               if (gid_gt(grp, GROUP_AT(group_info, mid)))
+               if (gid_gt(grp, group_info->gid[mid]))
                        left = mid + 1;
-               else if (gid_lt(grp, GROUP_AT(group_info, mid)))
+               else if (gid_lt(grp, group_info->gid[mid]))
                        right = mid;
                else
                        return 1;