Re: [PATCH ghak90 V6 03/10] audit: read container ID of a process

Richard Guy Briggs <rgb(a)redhat.com&gt; writes: > Add support for reading the audit container identifier from the proc > filesystem. > > This is a read from the proc entry of the form > /proc/PID/audit_containerid where PID is the process ID of the task > whose audit container identifier is sought. > > The read expects up to a u64 value (unset: 18446744073709551615). > > This read requires CAP_AUDIT_CONTROL. This scares me. As this seems to make it easy to reuse an audit containerid for non-audit purporses.

I would think it would be safer and easier to poke audit and ask it to log a message with your audit container id.

Eric > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > Acked-by: Serge Hallyn <serge(a)hallyn.com&gt; > Acked-by: Neil Horman <nhorman(a)tuxdriver.com&gt; > Reviewed-by: Ondrej Mosnacek <omosnace(a)redhat.com&gt; > --- > fs/proc/base.c | 25 ++++++++++++++++++++++--- > 1 file changed, 22 insertions(+), 3 deletions(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 43fd0c4b87de..acc70239d0cb 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -1211,7 +1211,7 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf, > }; > > #ifdef CONFIG_AUDIT > -#define TMPBUFLEN 11 > +#define TMPBUFLEN 21 > static ssize_t proc_loginuid_read(struct file * file, char __user * buf, > size_t count, loff_t *ppos) > { > @@ -1295,6 +1295,24 @@ static ssize_t proc_sessionid_read(struct file * file, char __user * buf, > .llseek = generic_file_llseek, > }; > > +static ssize_t proc_contid_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]; > + > + if (!task) > + return -ESRCH; > + /* if we don't have caps, reject */ > + if (!capable(CAP_AUDIT_CONTROL)) > + return -EPERM; > + length = scnprintf(tmpbuf, TMPBUFLEN, "%llu", audit_get_contid(task)); > + put_task_struct(task); > + return simple_read_from_buffer(buf, count, ppos, tmpbuf, length); > +} > + > static ssize_t proc_contid_write(struct file *file, const char __user *buf, > size_t count, loff_t *ppos) > { > @@ -1325,6 +1343,7 @@ static ssize_t proc_contid_write(struct file *file, const char __user *buf, > } > > static const struct file_operations proc_contid_operations = { > + .read = proc_contid_read, > .write = proc_contid_write, > .llseek = generic_file_llseek, > }; > @@ -3067,7 +3086,7 @@ static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns, > #ifdef CONFIG_AUDIT > REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), > REG("sessionid", S_IRUGO, proc_sessionid_operations), > - REG("audit_containerid", S_IWUSR, proc_contid_operations), > + REG("audit_containerid", S_IWUSR|S_IRUSR, proc_contid_operations), > #endif > #ifdef CONFIG_FAULT_INJECTION > REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), > @@ -3466,7 +3485,7 @@ static int proc_tid_comm_permission(struct inode *inode, int mask) > #ifdef CONFIG_AUDIT > REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), > REG("sessionid", S_IRUGO, proc_sessionid_operations), > - REG("audit_containerid", S_IWUSR, proc_contid_operations), > + REG("audit_containerid", S_IWUSR|S_IRUSR, proc_contid_operations), > #endif > #ifdef CONFIG_FAULT_INJECTION > REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),