On Fri, 16 Mar 2018 05:00:28 -0400 Richard Guy Briggs <rgb@xxxxxxxxxx> 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@xxxxxxxxxx> > --- > 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. Thanks, -Steve > + from_kuid(&init_user_ns, > audit_get_loginuid(current)), > + tty ? tty_name(tty) : "(none)", > audit_get_sessionid(current), > + task_tgid_nr(task), oldcontainerid, > containerid, !rc); + > + audit_put_tty(tty); > + audit_log_end(ab); > +} > + > +/** > + * audit_set_containerid - set current task's audit_context > containerid > + * @containerid: containerid value > + * > + * Returns 0 on success, -EPERM on permission failure. > + * > + * Called (set) from fs/proc/base.c::proc_containerid_write(). > + */ > +int audit_set_containerid(struct task_struct *task, u64 containerid) > +{ > + u64 oldcontainerid; > + int rc; > + > + oldcontainerid = audit_get_containerid(task); > + > + rc = audit_set_containerid_perm(task, containerid); > + if (!rc) { > + task_lock(task); > + task->containerid = containerid; > + task_unlock(task); > + } > + > + audit_log_set_containerid(task, oldcontainerid, containerid, > rc); > + return rc; > +} > + > /** > * __audit_mq_open - record audit data for a POSIX MQ open > * @oflag: open flag -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
