On 2018-06-06 13:56, Steve Grubb wrote: > On Wednesday, June 6, 2018 12:58:28 PM EDT Richard Guy Briggs wrote: > > Implement the proc fs write to set the audit container identifier of a > > process, emitting an AUDIT_CONTAINER_ID record to document the event. > > > > This is a write from the container orchestrator task to a proc entry of > > the form /proc/PID/audit_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). > > > > The writer must have capability CAP_AUDIT_CONTROL. > > > > This will produce a record such as this: > > type=CONTAINER_ID msg=audit(2018-06-06 12:39:29.636:26949) : op=set > > opid=2209 old-contid=18446744073709551615 contid=123456 pid=628 auid=root > > uid=root tty=ttyS0 ses=1 > > subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=bash > > exe=/usr/bin/bash res=yes > > > > 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 audit container identifier values are > > given in the "contid" fields, while res indicates its success. > > > > It is not permitted to unset or re-set the audit container identifier. > > A child inherits its parent's audit container identifier, but then can > > be set only once after. > > > > See: https://github.com/linux-audit/audit-kernel/issues/90 > > See: https://github.com/linux-audit/audit-userspace/issues/51 > > See: https://github.com/linux-audit/audit-testsuite/issues/64 > > See: > > https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID > > > > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx> > > --- > > fs/proc/base.c | 37 ++++++++++++++++++++++++ > > include/linux/audit.h | 25 ++++++++++++++++ > > include/uapi/linux/audit.h | 2 ++ > > kernel/auditsc.c | 71 > > ++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 135 > > insertions(+) > > > > diff --git a/fs/proc/base.c b/fs/proc/base.c > > index eafa39a..318dff4 100644 > > --- a/fs/proc/base.c > > +++ b/fs/proc/base.c > > @@ -1302,6 +1302,41 @@ static ssize_t proc_sessionid_read(struct file * > > file, char __user * buf, .read = proc_sessionid_read, > > .llseek = generic_file_llseek, > > }; > > + > > +static ssize_t proc_contid_write(struct file *file, const char __user > > *buf, + size_t count, loff_t *ppos) > > +{ > > + struct inode *inode = file_inode(file); > > + u64 contid; > > + 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, &contid); > > + if (rv < 0) { > > + put_task_struct(task); > > + return rv; > > + } > > + > > + rv = audit_set_contid(task, contid); > > + put_task_struct(task); > > + if (rv < 0) > > + return rv; > > + return count; > > +} > > + > > +static const struct file_operations proc_contid_operations = { > > + .write = proc_contid_write, > > + .llseek = generic_file_llseek, > > +}; > > + > > #endif > > > > #ifdef CONFIG_FAULT_INJECTION > > @@ -2995,6 +3030,7 @@ 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("audit_containerid", S_IWUSR, proc_contid_operations), > > #endif > > #ifdef CONFIG_FAULT_INJECTION > > REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), > > @@ -3386,6 +3422,7 @@ 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("audit_containerid", S_IWUSR, proc_contid_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 4f824c4..497cd81 100644 > > --- a/include/linux/audit.h > > +++ b/include/linux/audit.h > > @@ -219,6 +219,8 @@ static inline void audit_log_task_info(struct > > audit_buffer *ab, struct audit_task_info { > > kuid_t loginuid; > > unsigned int sessionid; > > + u64 contid; > > + bool inherited; /* containerid inheritance */ > > struct audit_context *ctx; > > }; > > extern struct audit_task_info init_struct_audit; > > @@ -331,6 +333,7 @@ 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_contid(struct task_struct *tsk, u64 contid); > > > > static inline kuid_t audit_get_loginuid(struct task_struct *tsk) > > { > > @@ -348,6 +351,14 @@ static inline unsigned int audit_get_sessionid(struct > > task_struct *tsk) return AUDIT_SID_UNSET; > > } > > > > +static inline u64 audit_get_contid(struct task_struct *tsk) > > +{ > > + if (!tsk->audit) > > + return AUDIT_CID_UNSET; > > + else > > + return tsk->audit->contid; > > +} > > + > > 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); > > @@ -542,6 +553,10 @@ static inline unsigned int audit_get_sessionid(struct > > task_struct *tsk) { > > return AUDIT_SID_UNSET; > > } > > +static inline kuid_t audit_get_contid(struct task_struct *tsk) > > +{ > > + return AUDIT_CID_UNSET; > > +} > > static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp) > > { } > > static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid, > > @@ -606,6 +621,16 @@ static inline bool audit_loginuid_set(struct > > task_struct *tsk) return uid_valid(audit_get_loginuid(tsk)); > > } > > > > +static inline bool cid_valid(u64 contid) > > +{ > > + return contid != AUDIT_CID_UNSET; > > +} > > + > > +static inline bool audit_contid_set(struct task_struct *tsk) > > +{ > > + return cid_valid(audit_get_contid(tsk)); > > +} > > + > > 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/uapi/linux/audit.h b/include/uapi/linux/audit.h > > index 04f9bd2..c3b1aca 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_ID 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 */ > > @@ -466,6 +467,7 @@ struct audit_tty_status { > > > > #define AUDIT_UID_UNSET (unsigned int)-1 > > #define AUDIT_SID_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 59ef7a81..611e926 100644 > > --- a/kernel/auditsc.c > > +++ b/kernel/auditsc.c > > @@ -956,6 +956,8 @@ int audit_alloc(struct task_struct *tsk) > > return -ENOMEM; > > info->loginuid = audit_get_loginuid(current); > > info->sessionid = audit_get_sessionid(current); > > + info->contid = audit_get_contid(current); > > + info->inherited = true; > > tsk->audit = info; > > > > if (likely(!audit_ever_enabled)) > > @@ -985,6 +987,8 @@ int audit_alloc(struct task_struct *tsk) > > struct audit_task_info init_struct_audit = { > > .loginuid = INVALID_UID, > > .sessionid = AUDIT_SID_UNSET, > > + .contid = AUDIT_CID_UNSET, > > + .inherited = true, > > .ctx = NULL, > > }; > > > > @@ -2112,6 +2116,73 @@ int audit_set_loginuid(kuid_t loginuid) > > } > > > > /** > > + * audit_set_contid - set current task's audit_context contid > > + * @contid: contid value > > + * > > + * Returns 0 on success, -EPERM on permission failure. > > + * > > + * Called (set) from fs/proc/base.c::proc_contid_write(). > > + */ > > +int audit_set_contid(struct task_struct *task, u64 contid) > > +{ > > + u64 oldcontid; > > + int rc = 0; > > + struct audit_buffer *ab; > > + uid_t uid; > > + struct tty_struct *tty; > > + char comm[sizeof(current->comm)]; > > + > > + /* Can't set if audit disabled */ > > + if (!task->audit) > > + return -ENOPROTOOPT; > > + oldcontid = audit_get_contid(task); > > + /* Don't allow the audit containerid to be unset */ > > + if (!cid_valid(contid)) > > + rc = -EINVAL; > > + /* if we don't have caps, reject */ > > + else if (!capable(CAP_AUDIT_CONTROL)) > > + rc = -EPERM; > > + /* if task has children or is not single-threaded, deny */ > > + else if (!list_empty(&task->children)) > > + rc = -EBUSY; > > + else if (!(thread_group_leader(task) && thread_group_empty(task))) > > + rc = -EALREADY; > > + /* it is already set, and not inherited from the parent, reject */ > > + else if (cid_valid(oldcontid) && !task->audit->inherited) > > + rc = -EEXIST; > > + if (!rc) { > > + task_lock(task); > > + task->audit->contid = contid; > > + task->audit->inherited = false; > > + task_unlock(task); > > + } > > + > > + if (!audit_enabled) > > + return rc; > > + > > + ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONTAINER_ID); > > + if (!ab) > > + return rc; > > + > > + uid = from_kuid(&init_user_ns, task_uid(current)); > > + tty = audit_get_tty(current); > > + audit_log_format(ab, "op=set opid=%d old-contid=%llu contid=%llu pid=%d > > uid=%u auid=%u tty=%s ses=%u", + task_tgid_nr(task), oldcontid, > contid, > > + task_tgid_nr(current), uid > > + from_kuid(&init_user_ns, audit_get_loginuid(current)), > > + tty ? tty_name(tty) : "(none)", > > + audit_get_sessionid(current)); > > The event code doesn't match the example event at the top. (uid and auid are > transposed.) But the code looks right. Hmmm, I thought I checked that explicitly... That event sample must have come from the previous compile before I fixed that. > Ack for the event format. Thanks! > -Steve > > > + audit_put_tty(tty); > > + audit_log_task_context(ab); > > + audit_log_format(ab, " comm="); > > + audit_log_untrustedstring(ab, get_task_comm(comm, current)); > > + audit_log_d_path_exe(ab, current->mm); > > + audit_log_format(ab, " res=%d", !rc); > > + audit_log_end(ab); > > + return rc; > > +} > > + > > +/** > > * __audit_mq_open - record audit data for a POSIX MQ open > > * @oflag: open flag > > * @mode: mode bits - RGB -- Richard Guy Briggs <rgb@xxxxxxxxxx> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635 -- 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
