Re: [RFC PATCH ghak32 V2 13/13] debug audit: read container ID of a process

Add support for reading the container ID from the proc filesystem.

This is a read from the proc entry of the form /proc/PID/containerid where PID is the process ID of the task whose container ID is sought. The read expects up to a u64 value (unset: 18446744073709551615). Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; --- fs/proc/base.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 6ce4fbe..f66d1e2 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1300,6 +1300,21 @@ static ssize_t proc_sessionid_read(struct file * file, char __user * buf, .llseek = generic_file_llseek, }; +static ssize_t proc_containerid_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file_inode(file); + struct task_struct *task = get_proc_task(inode); + ssize_t length; + char tmpbuf[TMPBUFLEN*2]; + + if (!task) + return -ESRCH; + length = scnprintf(tmpbuf, TMPBUFLEN*2, "%llu", audit_get_containerid(task)); + put_task_struct(task); + return simple_read_from_buffer(buf, count, ppos, tmpbuf, length); +} + static ssize_t proc_containerid_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { @@ -1330,6 +1345,7 @@ static ssize_t proc_containerid_write(struct file *file, const char __user *buf, } static const struct file_operations proc_containerid_operations = { + .read = proc_containerid_read, .write = proc_containerid_write, .llseek = generic_file_llseek, }; @@ -2996,7 +3012,7 @@ 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), + REG("containerid", S_IWUSR|S_IRUSR, proc_containerid_operations), #endif #ifdef CONFIG_FAULT_INJECTION REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), @@ -3391,7 +3407,7 @@ 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), + REG("containerid", S_IWUSR|S_IRUSR, proc_containerid_operations), #endif #ifdef CONFIG_FAULT_INJECTION REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),