diff options
| author | Eric Paris <eparis@redhat.com> | 2013-05-24 09:49:14 -0400 |
|---|---|---|
| committer | Eric Paris <eparis@redhat.com> | 2013-11-05 11:08:09 -0500 |
| commit | 81407c84ace88368ff23abb81caaeacf050c8450 (patch) | |
| tree | 16073582364ac97b798010640da348a68460b73d | |
| parent | 83fa6bbe4c4541ae748b550b4ec391f8a0acfe94 (diff) | |
audit: allow unsetting the loginuid (with priv)
If a task has CAP_AUDIT_CONTROL allow that task to unset their loginuid.
This would allow a child of that task to set their loginuid without
CAP_AUDIT_CONTROL. Thus when launching a new login daemon, a
priviledged helper would be able to unset the loginuid and then the
daemon, which may be malicious user facing, do not need priv to function
correctly.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
| -rw-r--r-- | fs/proc/base.c | 14 | ||||
| -rw-r--r-- | kernel/auditsc.c | 4 |
2 files changed, 13 insertions, 5 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 1485e38daaa3..03c8d747be48 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1151,10 +1151,16 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf, goto out_free_page; } - kloginuid = make_kuid(file->f_cred->user_ns, loginuid); - if (!uid_valid(kloginuid)) { - length = -EINVAL; - goto out_free_page; + + /* is userspace tring to explicitly UNSET the loginuid? */ + if (loginuid == AUDIT_UID_UNSET) { + kloginuid = INVALID_UID; + } else { + kloginuid = make_kuid(file->f_cred->user_ns, loginuid); + if (!uid_valid(kloginuid)) { + length = -EINVAL; + goto out_free_page; + } } length = audit_set_loginuid(kloginuid); diff --git a/kernel/auditsc.c b/kernel/auditsc.c index b55788bf1607..c75d7813aef2 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -2019,7 +2019,9 @@ int audit_set_loginuid(kuid_t loginuid) if (rc) goto out; - sessionid = atomic_inc_return(&session_id); + /* are we setting or clearing? */ + if (uid_valid(loginuid)) + sessionid = atomic_inc_return(&session_id); task->sessionid = sessionid; task->loginuid = loginuid; |