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| author | Eric W. Biederman <ebiederm@xmission.com> | 2016-06-30 16:31:01 -0500 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2016-07-05 15:12:05 -0500 |
| commit | d49d37624a1931c2f3b5d0cbe95bd5181cbdc279 (patch) | |
| tree | f81e4129a5a393df64b6b674ed9aae83a404f707 /fs/quota | |
| parent | 036d523641c66bef713042894a17f4335f199e49 (diff) | |
| download | linux-d49d37624a1931c2f3b5d0cbe95bd5181cbdc279.tar.gz linux-d49d37624a1931c2f3b5d0cbe95bd5181cbdc279.tar.bz2 linux-d49d37624a1931c2f3b5d0cbe95bd5181cbdc279.zip | |
quota: Ensure qids map to the filesystem
Introduce the helper qid_has_mapping and use it to ensure that the
quota system only considers qids that map to the filesystems
s_user_ns.
In practice for quota supporting filesystems today this is the exact
same check as qid_valid. As only 0xffffffff aka (qid_t)-1 does not
map into init_user_ns.
Replace the qid_valid calls with qid_has_mapping as values come in
from userspace. This is harmless today and it prepares the quota
system to work on filesystems with quotas but mounted by unprivileged
users.
Call qid_has_mapping from dqget. This ensures the passed in qid has a
prepresentation on the underlying filesystem. Previously this was
unnecessary as filesystesm never had qids that could not map. With
the introduction of filesystems outside of s_user_ns this will not
remain true.
All of this ensures the quota code never has to deal with qids that
don't map to the underlying filesystem.
Cc: Jan Kara <jack@suse.cz>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/quota')
| -rw-r--r-- | fs/quota/dquot.c | 3 | ||||
| -rw-r--r-- | fs/quota/quota.c | 12 |
2 files changed, 9 insertions, 6 deletions
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index ff21980d0119..74706b6aa747 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -841,6 +841,9 @@ struct dquot *dqget(struct super_block *sb, struct kqid qid) unsigned int hashent = hashfn(sb, qid); struct dquot *dquot, *empty = NULL; + if (!qid_has_mapping(sb->s_user_ns, qid)) + return ERR_PTR(-EINVAL); + if (!sb_has_quota_active(sb, qid.type)) return ERR_PTR(-ESRCH); we_slept: diff --git a/fs/quota/quota.c b/fs/quota/quota.c index 0f10ee9892ce..73f6f4cf0a21 100644 --- a/fs/quota/quota.c +++ b/fs/quota/quota.c @@ -211,7 +211,7 @@ static int quota_getquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->get_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; ret = sb->s_qcop->get_dqblk(sb, qid, &fdq); if (ret) @@ -237,7 +237,7 @@ static int quota_getnextquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->get_nextdqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; ret = sb->s_qcop->get_nextdqblk(sb, &qid, &fdq); if (ret) @@ -288,7 +288,7 @@ static int quota_setquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->set_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; copy_from_if_dqblk(&fdq, &idq); return sb->s_qcop->set_dqblk(sb, qid, &fdq); @@ -581,7 +581,7 @@ static int quota_setxquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->set_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; /* Are we actually setting timer / warning limits for all users? */ if (from_kqid(&init_user_ns, qid) == 0 && @@ -642,7 +642,7 @@ static int quota_getxquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->get_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; ret = sb->s_qcop->get_dqblk(sb, qid, &qdq); if (ret) @@ -669,7 +669,7 @@ static int quota_getnextxquota(struct super_block *sb, int type, qid_t id, if (!sb->s_qcop->get_nextdqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); - if (!qid_valid(qid)) + if (!qid_has_mapping(sb->s_user_ns, qid)) return -EINVAL; ret = sb->s_qcop->get_nextdqblk(sb, &qid, &qdq); if (ret) |