Re: [RFC PATCH ghak32 V2 01/13] audit: add container id

On Friday, June 1, 2018 5:04:55 PM EDT Richard Guy Briggs wrote: > Re: [RFC PATCH ghak32 V2 01/13] audit: add container id > > From: Richard Guy Briggs <rgb(a)redhat.com&gt; > To: Me > CC: linux-api(a)vger.kernel.org, containers(a)lists.linux-foundation.org, LKML > <linux-kernel(a)vger.kernel.org&gt;, eparis(a)parisplace.org, ... Date: 6/1/18 > 5:04 PM > > On 2018-05-17 17:00, Steve Grubb wrote: > > On Fri, 16 Mar 2018 05:00:28 -0400 > > > > Richard Guy Briggs <rgb(a)redhat.com&gt; wrote: > > > Implement the proc fs write to set the audit container ID of a > > > process, emitting an AUDIT_CONTAINER record to document the event. > > > > > > This is a write from the container orchestrator task to a proc entry > > > of the form /proc/PID/containerid where PID is the process ID of the > > > newly created task that is to become the first task in a container, > > > or an additional task added to a container. > > > > > > The write expects up to a u64 value (unset: 18446744073709551615). > > > > > > This will produce a record such as this: > > > type=CONTAINER msg=audit(1519903238.968:261): op=set pid=596 uid=0 > > > subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 > > > tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 > > > res=0 > > > > The was one thing I was wondering about. Currently when we set the > > loginuid, the record is AUDIT_LOGINUID. The corollary is that when we > > set the container id, the event should be AUDIT_CONTAINERID or > > AUDIT_CONTAINER_ID. > > > > During syscall events, the path info is returned in a a record simply > > called AUDIT_PATH, cwd info is returned in AUDIT_CWD. So, rather than > > calling the record that gets attached to everything > > AUDIT_CONTAINER_INFO, how about simply AUDIT_CONTAINER. > > > > > The "op" field indicates an initial set. The "pid" to "ses" fields > > > are the orchestrator while the "opid" field is the object's PID, the > > > process being "contained". Old and new container ID values are given > > > in the "contid" fields, while res indicates its success. > > > > > > It is not permitted to self-set, unset or re-set the container ID. A > > > child inherits its parent's container ID, but then can be set only > > > once after. > > > > > > See: https://github.com/linux-audit/audit-kernel/issues/32 > > > > > > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > > > --- > > > fs/proc/base.c | 37 ++++++++++++++++++++ > > > include/linux/audit.h | 16 +++++++++ > > > include/linux/init_task.h | 4 ++- > > > include/linux/sched.h | 1 + > > > include/uapi/linux/audit.h | 2 ++ > > > kernel/auditsc.c | 84 > > > ++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 143 > > > insertions(+), 1 deletion(-) > > > > > > diff --git a/fs/proc/base.c b/fs/proc/base.c > > > index 60316b5..6ce4fbe 100644 > > > --- a/fs/proc/base.c > > > +++ b/fs/proc/base.c > > > @@ -1299,6 +1299,41 @@ static ssize_t proc_sessionid_read(struct file > > > * file, char __user * buf, .read = proc_sessionid_read, > > > .llseek = generic_file_llseek, > > > }; > > > + > > > +static ssize_t proc_containerid_write(struct file *file, const char > > > __user *buf, > > > + size_t count, loff_t *ppos) > > > +{ > > > + struct inode *inode = file_inode(file); > > > + u64 containerid; > > > + int rv; > > > + struct task_struct *task = get_proc_task(inode); > > > + > > > + if (!task) > > > + return -ESRCH; > > > + if (*ppos != 0) { > > > + /* No partial writes. */ > > > + put_task_struct(task); > > > + return -EINVAL; > > > + } > > > + > > > + rv = kstrtou64_from_user(buf, count, 10, &containerid); > > > + if (rv < 0) { > > > + put_task_struct(task); > > > + return rv; > > > + } > > > + > > > + rv = audit_set_containerid(task, containerid); > > > + put_task_struct(task); > > > + if (rv < 0) > > > + return rv; > > > + return count; > > > +} > > > + > > > +static const struct file_operations proc_containerid_operations = { > > > + .write = proc_containerid_write, > > > + .llseek = generic_file_llseek, > > > +}; > > > + > > > #endif > > > > > > #ifdef CONFIG_FAULT_INJECTION > > > @@ -2961,6 +2996,7 @@ static int proc_pid_patch_state(struct seq_file > > > *m, struct pid_namespace *ns, #ifdef CONFIG_AUDITSYSCALL > > > REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), > > > REG("sessionid", S_IRUGO, proc_sessionid_operations), > > > + REG("containerid", S_IWUSR, proc_containerid_operations), > > > #endif > > > #ifdef CONFIG_FAULT_INJECTION > > > REG("make-it-fail", S_IRUGO|S_IWUSR, > > > proc_fault_inject_operations), @@ -3355,6 +3391,7 @@ static int > > > proc_tid_comm_permission(struct inode *inode, int mask) #ifdef > > > CONFIG_AUDITSYSCALL REG("loginuid", S_IWUSR|S_IRUGO, > > > proc_loginuid_operations), REG("sessionid", S_IRUGO, > > > proc_sessionid_operations), > > > + REG("containerid", S_IWUSR, proc_containerid_operations), > > > #endif > > > #ifdef CONFIG_FAULT_INJECTION > > > REG("make-it-fail", S_IRUGO|S_IWUSR, > > > proc_fault_inject_operations), diff --git a/include/linux/audit.h > > > b/include/linux/audit.h index af410d9..fe4ba3f 100644 > > > --- a/include/linux/audit.h > > > +++ b/include/linux/audit.h > > > @@ -29,6 +29,7 @@ > > > > > > #define AUDIT_INO_UNSET ((unsigned long)-1) > > > #define AUDIT_DEV_UNSET ((dev_t)-1) > > > +#define INVALID_CID AUDIT_CID_UNSET > > > > > > struct audit_sig_info { > > > uid_t uid; > > > @@ -321,6 +322,7 @@ static inline void audit_ptrace(struct > > > task_struct *t) extern int auditsc_get_stamp(struct audit_context > > > *ctx, struct timespec64 *t, unsigned int *serial); > > > extern int audit_set_loginuid(kuid_t loginuid); > > > +extern int audit_set_containerid(struct task_struct *tsk, u64 > > > containerid); > > > static inline kuid_t audit_get_loginuid(struct task_struct *tsk) > > > { > > > @@ -332,6 +334,11 @@ static inline unsigned int > > > audit_get_sessionid(struct task_struct *tsk) return tsk->sessionid; > > > } > > > > > > +static inline u64 audit_get_containerid(struct task_struct *tsk) > > > +{ > > > + return tsk->containerid; > > > +} > > > + > > > extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp); > > > extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, > > > gid_t gid, umode_t mode); extern void __audit_bprm(struct > > > linux_binprm *bprm); @@ -517,6 +524,10 @@ static inline unsigned int > > > audit_get_sessionid(struct task_struct *tsk) { > > > return -1; > > > } > > > +static inline kuid_t audit_get_containerid(struct task_struct *tsk) > > > +{ > > > + return INVALID_CID; > > > +} > > > static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp) > > > { } > > > static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t > > > uid, @@ -581,6 +592,11 @@ static inline bool > > > audit_loginuid_set(struct task_struct *tsk) return > > > uid_valid(audit_get_loginuid(tsk)); } > > > > > > +static inline bool audit_containerid_set(struct task_struct *tsk) > > > +{ > > > + return audit_get_containerid(tsk) != INVALID_CID; > > > +} > > > + > > > static inline void audit_log_string(struct audit_buffer *ab, const > > > char *buf) { > > > audit_log_n_string(ab, buf, strlen(buf)); > > > diff --git a/include/linux/init_task.h b/include/linux/init_task.h > > > index 6a53262..046bd0a 100644 > > > --- a/include/linux/init_task.h > > > +++ b/include/linux/init_task.h > > > @@ -18,6 +18,7 @@ > > > #include <linux/sched/rt.h> > > > #include <linux/livepatch.h> > > > #include <linux/mm_types.h> > > > +#include <linux/audit.h> > > > > > > #include <asm/thread_info.h> > > > > > > @@ -120,7 +121,8 @@ > > > #ifdef CONFIG_AUDITSYSCALL > > > #define INIT_IDS \ > > > .loginuid = INVALID_UID, \ > > > - .sessionid = (unsigned int)-1, > > > + .sessionid = (unsigned int)-1, \ > > > + .containerid = INVALID_CID, > > > #else > > > #define INIT_IDS > > > #endif > > > diff --git a/include/linux/sched.h b/include/linux/sched.h > > > index d258826..1b82191 100644 > > > --- a/include/linux/sched.h > > > +++ b/include/linux/sched.h > > > @@ -796,6 +796,7 @@ struct task_struct { > > > #ifdef CONFIG_AUDITSYSCALL > > > kuid_t loginuid; > > > unsigned int sessionid; > > > + u64 containerid; > > > #endif > > > struct seccomp seccomp; > > > > > > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h > > > index 4e61a9e..921a71f 100644 > > > --- a/include/uapi/linux/audit.h > > > +++ b/include/uapi/linux/audit.h > > > @@ -71,6 +71,7 @@ > > > #define AUDIT_TTY_SET 1017 /* Set TTY auditing > > > status */ #define AUDIT_SET_FEATURE 1018 /* Turn an > > > audit feature on or off */ #define AUDIT_GET_FEATURE > > > 1019 /* Get which features are enabled */ +#define > > > AUDIT_CONTAINER 1020 /* Define the container id > > > and information */ #define AUDIT_FIRST_USER_MSG 1100 /* > > > Userspace messages mostly uninteresting to kernel */ #define > > > AUDIT_USER_AVC 1107 /* We filter this > > > differently */ @@ -465,6 +466,7 @@ struct audit_tty_status { }; > > > > > > #define AUDIT_UID_UNSET (unsigned int)-1 > > > +#define AUDIT_CID_UNSET ((u64)-1) > > > > > > /* audit_rule_data supports filter rules with both integer and string > > > * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > > index 4e0a4ac..29c8482 100644 > > > --- a/kernel/auditsc.c > > > +++ b/kernel/auditsc.c > > > @@ -2073,6 +2073,90 @@ int audit_set_loginuid(kuid_t loginuid) > > > return rc; > > > } > > > > > > +static int audit_set_containerid_perm(struct task_struct *task, u64 > > > containerid) +{ > > > + struct task_struct *parent; > > > + u64 pcontainerid, ccontainerid; > > > + > > > + /* Don't allow to set our own containerid */ > > > + if (current == task) > > > + return -EPERM; > > > + /* Don't allow the containerid to be unset */ > > > + if (!cid_valid(containerid)) > > > + return -EINVAL; > > > + /* if we don't have caps, reject */ > > > + if (!capable(CAP_AUDIT_CONTROL)) > > > + return -EPERM; > > > + /* if containerid is unset, allow */ > > > + if (!audit_containerid_set(task)) > > > + return 0; > > > + /* it is already set, and not inherited from the parent, > > > reject */ > > > + ccontainerid = audit_get_containerid(task); > > > + rcu_read_lock(); > > > + parent = rcu_dereference(task->real_parent); > > > + rcu_read_unlock(); > > > + task_lock(parent); > > > + pcontainerid = audit_get_containerid(parent); > > > + task_unlock(parent); > > > + if (ccontainerid != pcontainerid) > > > + return -EPERM; > > > + return 0; > > > +} > > > + > > > +static void audit_log_set_containerid(struct task_struct *task, u64 > > > oldcontainerid, > > > + u64 containerid, int rc) > > > +{ > > > + struct audit_buffer *ab; > > > + uid_t uid; > > > + struct tty_struct *tty; > > > + > > > + if (!audit_enabled) > > > + return; > > > + > > > + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONTAINER); > > > + if (!ab) > > > + return; > > > + > > > + uid = from_kuid(&init_user_ns, task_uid(current)); > > > + tty = audit_get_tty(current); > > > + > > > + audit_log_format(ab, "op=set pid=%d uid=%u", > > > task_tgid_nr(current), uid); > > > + audit_log_task_context(ab); > > > + audit_log_format(ab, " auid=%u tty=%s ses=%u opid=%d > > > old-contid=%llu contid=%llu res=%d", > > > > The preferred ordering would be: op, opid, old-contid, contid, pid, uid, > > tty, ses, subj, comm, exe, res. This groups the searchable fields > > together using the most common ordering so that parsing is simple. > > Where would you like auid? It appears that just before uid would be the > right place, if not in place of uid, but this is just a guess since it > isn't consistent. Just after the uid is the proper place. The most common sequence is: pid, uid, auid, tty, session, subject context, comm, exe.

-Steve