From c988afb5fa3fc450207c3dfc0ce535f4bfdae4d1 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 16 Feb 2010 03:44:50 -0500 Subject: [PATCH] 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 Signed-off-by: Jan Kara --- fs/quota/quota.c | 92 ++++++++++++++++-------------------------------- 1 file changed, 31 insertions(+), 61 deletions(-) diff --git a/fs/quota/quota.c b/fs/quota/quota.c index 9fde5cd84f8d..d0efe302b1c1 100644 --- a/fs/quota/quota.c +++ b/fs/quota/quota.c @@ -21,69 +21,30 @@ #include #include -/* 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 quota_getxquota(struct super_block *sb, int type, qid_t id, 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 @@ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special, 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; -- 2.30.2