quota: simplify permission checking
Stop having complicated different routines for checking permissions for
XQM vs "VFS" quotas. Instead do the checks for having sb->s_qcop and
a valid type directly in do_quotactl, and munge the *quotactl_valid functions
into a check_quotactl_permission helper that only checks for permissions.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 9fde5cd..d0efe30 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -21,69 +21,30 @@
#include <net/netlink.h>
#include <net/genetlink.h>
-/* Check validity of generic quotactl commands */
-static int generic_quotactl_valid(struct super_block *sb, int type, int cmd,
- qid_t id)
+static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
+ qid_t id)
{
- if (type >= MAXQUOTAS)
- return -EINVAL;
- if (!sb && cmd != Q_SYNC)
- return -ENODEV;
- /* Is operation supported? */
- if (sb && !sb->s_qcop)
- return -ENOSYS;
-
- /* Check privileges */
- if (cmd == Q_GETQUOTA) {
- if (((type == USRQUOTA && current_euid() != id) ||
- (type == GRPQUOTA && !in_egroup_p(id))) &&
- !capable(CAP_SYS_ADMIN))
- return -EPERM;
- }
- else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- return 0;
-}
-
-/* Check validity of XFS Quota Manager commands */
-static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd,
- qid_t id)
-{
- if (type >= XQM_MAXQUOTAS)
- return -EINVAL;
- if (!sb)
- return -ENODEV;
- if (!sb->s_qcop)
- return -ENOSYS;
-
- /* Check privileges */
- if (cmd == Q_XGETQUOTA) {
- if (((type == XQM_USRQUOTA && current_euid() != id) ||
- (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
- !capable(CAP_SYS_ADMIN))
- return -EPERM;
- } else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
+ switch (cmd) {
+ /* these commands do not require any special privilegues */
+ case Q_GETFMT:
+ case Q_SYNC:
+ case Q_GETINFO:
+ case Q_XGETQSTAT:
+ case Q_XQUOTASYNC:
+ break;
+ /* allow to query information for dquots we "own" */
+ case Q_GETQUOTA:
+ case Q_XGETQUOTA:
+ if ((type == USRQUOTA && current_euid() == id) ||
+ (type == GRPQUOTA && in_egroup_p(id)))
+ break;
+ /*FALLTHROUGH*/
+ default:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
}
- return 0;
-}
-
-static int check_quotactl_valid(struct super_block *sb, int type, int cmd,
- qid_t id)
-{
- int error;
-
- if (XQM_COMMAND(cmd))
- error = xqm_quotactl_valid(sb, type, cmd, id);
- else
- error = generic_quotactl_valid(sb, type, cmd, id);
- if (!error)
- error = security_quotactl(cmd, type, id, sb);
- return error;
+ return security_quotactl(cmd, type, id, sb);
}
#ifdef CONFIG_QUOTA
@@ -313,6 +274,17 @@
static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
void __user *addr)
{
+ int ret;
+
+ if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
+ return -EINVAL;
+ if (!sb->s_qcop)
+ return -ENOSYS;
+
+ ret = check_quotactl_permission(sb, type, cmd, id);
+ if (ret < 0)
+ return ret;
+
switch (cmd) {
case Q_QUOTAON:
return quota_quotaon(sb, type, cmd, id, addr);
@@ -413,9 +385,7 @@
if (IS_ERR(sb))
return PTR_ERR(sb);
- ret = check_quotactl_valid(sb, type, cmds, id);
- if (ret >= 0)
- ret = do_quotactl(sb, type, cmds, id, addr);
+ ret = do_quotactl(sb, type, cmds, id, addr);
drop_super(sb);
return ret;
