[PATCH 24/43] userns: Convert ptrace, kill, set_priority permission checks to work with kuids and kgids

"Eric W. Beiderman
2012-04-08T05:12:52Z

From: Eric W. Biederman <ebiederm@xmission.com>

Update the permission checks to use the new uid_eq and gid_eq helpers
and remove the now unnecessary user_ns equality comparison.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
kernel/ptrace.c | 13 ++++++-------
kernel/signal.c | 15 ++++++---------
kernel/sys.c | 18 ++++++++----------
3 files changed, 20 insertions(+), 26 deletions(-)

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 24e0a5a..a232bb5 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -198,13 +198,12 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
return 0;
rcu_read_lock();
tcred = __task_cred(task);
- if (cred->user_ns == tcred->user_ns &&
- (cred->uid == tcred->euid &&
- cred->uid == tcred->suid &&
- cred->uid == tcred->uid &&
- cred->gid == tcred->egid &&
- cred->gid == tcred->sgid &&
- cred->gid == tcred->gid))
+ if (uid_eq(cred->uid, tcred->euid) &&
+ uid_eq(cred->uid, tcred->suid) &&
+ uid_eq(cred->uid, tcred->uid) &&
+ gid_eq(cred->gid, tcred->egid) &&
+ gid_eq(cred->gid, tcred->sgid) &&
+ gid_eq(cred->gid, tcred->gid))
goto ok;
if (ptrace_has_cap(tcred->user_ns, mode))
goto ok;
diff --git a/kernel/signal.c b/kernel/signal.c
index d630327..9797939 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -767,11 +767,10 @@ static int kill_ok_by_cred(struct task_struct *t)
const struct cred *cred = current_cred();
const struct cred *tcred = __task_cred(t);

- if (cred->user_ns == tcred->user_ns &&
- (cred->euid == tcred->suid ||
- cred->euid == tcred->uid ||
- cred->uid == tcred->suid ||
- cred->uid == tcred->uid))
+ if (uid_eq(cred->euid, tcred->suid) ||
+ uid_eq(cred->euid, tcred->uid) ||
+ uid_eq(cred->uid, tcred->suid) ||
+ uid_eq(cred->uid, tcred->uid))
return 1;

if (ns_capable(tcred->user_ns, CAP_KILL))
@@ -1389,10 +1388,8 @@ static int kill_as_cred_perm(const struct cred *cred,
struct task_struct *target)
{
const struct cred *pcred = __task_cred(target);
- if (cred->user_ns != pcred->user_ns)
- return 0;
- if (cred->euid != pcred->suid && cred->euid != pcred->uid &&
- cred->uid != pcred->suid && cred->uid != pcred->uid)
+ if (uid_eq(cred->euid, pcred->suid) && uid_eq(cred->euid, pcred->uid) &&
+ uid_eq(cred->uid, pcred->suid) && uid_eq(cred->uid, pcred->uid))
return 0;
return 1;
}
diff --git a/kernel/sys.c b/kernel/sys.c
index aff09f2..f484077 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -131,9 +131,8 @@ static bool set_one_prio_perm(struct task_struct *p)
{
const struct cred *cred = current_cred(), *pcred = __task_cred(p);

- if (pcred->user_ns == cred->user_ns &&
- (pcred->uid == cred->euid ||
- pcred->euid == cred->euid))
+ if (uid_eq(pcred->uid, cred->euid) ||
+ uid_eq(pcred->euid, cred->euid))
return true;
if (ns_capable(pcred->user_ns, CAP_SYS_NICE))
return true;
@@ -1582,13 +1581,12 @@ static int check_prlimit_permission(struct task_struct *task)
return 0;

tcred = __task_cred(task);
- if (cred->user_ns == tcred->user_ns &&
- (cred->uid == tcred->euid &&
- cred->uid == tcred->suid &&
- cred->uid == tcred->uid &&
- cred->gid == tcred->egid &&
- cred->gid == tcred->sgid &&
- cred->gid == tcred->gid))
+ if (uid_eq(cred->uid, tcred->euid) &&
+ uid_eq(cred->uid, tcred->suid) &&
+ uid_eq(cred->uid, tcred->uid) &&
+ gid_eq(cred->gid, tcred->egid) &&
+ gid_eq(cred->gid, tcred->sgid) &&
+ gid_eq(cred->gid, tcred->gid))
return 0;
if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
return 0;
--
1.7.2.5