From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [PATCH ghak90 V6 03/10] audit: read container ID of a process Date: Fri, 19 Jul 2019 11:03:35 -0500 Message-ID: <87d0i6dnag.fsf@xmission.com> References: <846df5e5bf5a49094fede082a2ace135ab6f5772.1554732921.git.rgb@redhat.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <846df5e5bf5a49094fede082a2ace135ab6f5772.1554732921.git.rgb@redhat.com> (Richard Guy Briggs's message of "Mon, 8 Apr 2019 23:39:10 -0400") Sender: linux-kernel-owner@vger.kernel.org To: Richard Guy Briggs Cc: containers@lists.linux-foundation.org, linux-api@vger.kernel.org, Linux-Audit Mailing List , linux-fsdevel@vger.kernel.org, LKML , netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, Paul Moore , sgrubb@redhat.com, omosnace@redhat.com, dhowells@redhat.com, simo@redhat.com, eparis@parisplace.org, serge@hallyn.com, nhorman@tuxdriver.com List-Id: linux-api@vger.kernel.org Richard Guy Briggs 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 > Acked-by: Serge Hallyn > Acked-by: Neil Horman > Reviewed-by: Ondrej Mosnacek > --- > 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),