The tty field was missing from AUDIT_LOGIN events.
Refactor code to create a new function audit_get_tty(), using it to
replace the call in audit_log_task_info() and to add it to
audit_log_set_loginuid().
Signed-off-by: Richard Guy Briggs <[email protected]>
---
include/linux/audit.h | 18 ++++++++++++++++++
kernel/audit.c | 11 +----------
kernel/auditsc.c | 5 +++--
3 files changed, 22 insertions(+), 12 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index b40ed5d..20c6649 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -26,6 +26,7 @@
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <uapi/linux/audit.h>
+#include <linux/tty.h>
#define AUDIT_INO_UNSET ((unsigned long)-1)
#define AUDIT_DEV_UNSET ((dev_t)-1)
@@ -343,6 +344,19 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
return tsk->sessionid;
}
+static inline char *audit_get_tty(struct task_struct *tsk)
+{
+ char *tty;
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
+ tty = tsk->signal->tty->name;
+ else
+ tty = "(none)";
+ spin_unlock_irq(&tsk->sighand->siglock);
+ return tty;
+}
+
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);
@@ -500,6 +514,10 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
{
return -1;
}
+static inline char *audit_get_tty(struct task_struct *tsk)
+{
+ return "(invalid)";
+}
static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
{ }
static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid,
diff --git a/kernel/audit.c b/kernel/audit.c
index 3a3e5de..fae11df 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -64,7 +64,6 @@
#include <linux/security.h>
#endif
#include <linux/freezer.h>
-#include <linux/tty.h>
#include <linux/pid_namespace.h>
#include <net/netns/generic.h>
@@ -1873,7 +1872,6 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
{
const struct cred *cred;
char comm[sizeof(tsk->comm)];
- char *tty;
if (!ab)
return;
@@ -1881,13 +1879,6 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
/* tsk == current */
cred = current_cred();
- spin_lock_irq(&tsk->sighand->siglock);
- if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
- tty = tsk->signal->tty->name;
- else
- tty = "(none)";
- spin_unlock_irq(&tsk->sighand->siglock);
-
audit_log_format(ab,
" ppid=%d pid=%d auid=%u uid=%u gid=%u"
" euid=%u suid=%u fsuid=%u"
@@ -1903,7 +1894,7 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
from_kgid(&init_user_ns, cred->egid),
from_kgid(&init_user_ns, cred->sgid),
from_kgid(&init_user_ns, cred->fsgid),
- tty, audit_get_sessionid(tsk));
+ audit_get_tty(tsk), audit_get_sessionid(tsk));
audit_log_format(ab, " comm=");
audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 195ffae..a0467fb 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1993,8 +1993,9 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
return;
audit_log_format(ab, "pid=%d uid=%u", task_pid_nr(current), uid);
audit_log_task_context(ab);
- audit_log_format(ab, " old-auid=%u auid=%u old-ses=%u ses=%u res=%d",
- oldloginuid, loginuid, oldsessionid, sessionid, !rc);
+ audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
+ oldloginuid, loginuid, audit_get_tty(current),
+ oldsessionid, sessionid, !rc);
audit_log_end(ab);
}
--
1.7.1
Hi Richard,
On 04/13/2016 04:25 PM, Richard Guy Briggs wrote:
> The tty field was missing from AUDIT_LOGIN events.
>
> Refactor code to create a new function audit_get_tty(), using it to
> replace the call in audit_log_task_info() and to add it to
> audit_log_set_loginuid().
>
> Signed-off-by: Richard Guy Briggs <[email protected]>
> ---
> include/linux/audit.h | 18 ++++++++++++++++++
> kernel/audit.c | 11 +----------
> kernel/auditsc.c | 5 +++--
> 3 files changed, 22 insertions(+), 12 deletions(-)
>
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index b40ed5d..20c6649 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -26,6 +26,7 @@
> #include <linux/sched.h>
> #include <linux/ptrace.h>
> #include <uapi/linux/audit.h>
> +#include <linux/tty.h>
>
> #define AUDIT_INO_UNSET ((unsigned long)-1)
> #define AUDIT_DEV_UNSET ((dev_t)-1)
> @@ -343,6 +344,19 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
> return tsk->sessionid;
> }
>
> +static inline char *audit_get_tty(struct task_struct *tsk)
> +{
> + char *tty;
> +
> + spin_lock_irq(&tsk->sighand->siglock);
> + if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
> + tty = tsk->signal->tty->name;
> + else
> + tty = "(none)";
> + spin_unlock_irq(&tsk->sighand->siglock);
This is unsafe because the tty could be immediately torn down after the
siglock is dropped, and return a dangling ptr.
> + return tty;
> +}
> +
> 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);
> @@ -500,6 +514,10 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
> {
> return -1;
> }
> +static inline char *audit_get_tty(struct task_struct *tsk)
> +{
> + return "(invalid)";
> +}
> static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
> { }
> static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid,
> diff --git a/kernel/audit.c b/kernel/audit.c
> index 3a3e5de..fae11df 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -64,7 +64,6 @@
> #include <linux/security.h>
> #endif
> #include <linux/freezer.h>
> -#include <linux/tty.h>
> #include <linux/pid_namespace.h>
> #include <net/netns/generic.h>
>
> @@ -1873,7 +1872,6 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
> {
> const struct cred *cred;
> char comm[sizeof(tsk->comm)];
> - char *tty;
struct tty_struct *tty;
>
> if (!ab)
> return;
> @@ -1881,13 +1879,6 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
> /* tsk == current */
> cred = current_cred();
>
> - spin_lock_irq(&tsk->sighand->siglock);
> - if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
> - tty = tsk->signal->tty->name;
> - else
> - tty = "(none)";
> - spin_unlock_irq(&tsk->sighand->siglock);
tty = get_current_tty();
> -
> audit_log_format(ab,
> " ppid=%d pid=%d auid=%u uid=%u gid=%u"
> " euid=%u suid=%u fsuid=%u"
> @@ -1903,7 +1894,7 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
> from_kgid(&init_user_ns, cred->egid),
> from_kgid(&init_user_ns, cred->sgid),
> from_kgid(&init_user_ns, cred->fsgid),
> - tty, audit_get_sessionid(tsk));
> + audit_get_tty(tsk), audit_get_sessionid(tsk));
tty_name(tty), ....);
^^^^^^^^^^
returns "NULL tty" if tty == NULL
tty_kref_put(tty);
>
> audit_log_format(ab, " comm=");
> audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 195ffae..a0467fb 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -1993,8 +1993,9 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
> return;
> audit_log_format(ab, "pid=%d uid=%u", task_pid_nr(current), uid);
> audit_log_task_context(ab);
> - audit_log_format(ab, " old-auid=%u auid=%u old-ses=%u ses=%u res=%d",
> - oldloginuid, loginuid, oldsessionid, sessionid, !rc);
tty = get_current_tty();
> + audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
> + oldloginuid, loginuid, audit_get_tty(current),
......., tty_name(tty),
> + oldsessionid, sessionid, !rc);
tty_kref_put(tty);
Regards,
Peter Hurley
> audit_log_end(ab);
> }
>
>
On 16/04/13, Peter Hurley wrote:
> Hi Richard,
Hi Peter,
> On 04/13/2016 04:25 PM, Richard Guy Briggs wrote:
> > The tty field was missing from AUDIT_LOGIN events.
> >
> > Refactor code to create a new function audit_get_tty(), using it to
> > replace the call in audit_log_task_info() and to add it to
> > audit_log_set_loginuid().
> >
> > Signed-off-by: Richard Guy Briggs <[email protected]>
> > ---
> > include/linux/audit.h | 18 ++++++++++++++++++
> > kernel/audit.c | 11 +----------
> > kernel/auditsc.c | 5 +++--
> > 3 files changed, 22 insertions(+), 12 deletions(-)
> >
> > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > index b40ed5d..20c6649 100644
> > --- a/include/linux/audit.h
> > +++ b/include/linux/audit.h
> > @@ -26,6 +26,7 @@
> > #include <linux/sched.h>
> > #include <linux/ptrace.h>
> > #include <uapi/linux/audit.h>
> > +#include <linux/tty.h>
> >
> > #define AUDIT_INO_UNSET ((unsigned long)-1)
> > #define AUDIT_DEV_UNSET ((dev_t)-1)
> > @@ -343,6 +344,19 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
> > return tsk->sessionid;
> > }
> >
> > +static inline char *audit_get_tty(struct task_struct *tsk)
> > +{
> > + char *tty;
> > +
> > + spin_lock_irq(&tsk->sighand->siglock);
> > + if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
> > + tty = tsk->signal->tty->name;
> > + else
> > + tty = "(none)";
> > + spin_unlock_irq(&tsk->sighand->siglock);
>
> This is unsafe because the tty could be immediately torn down after the
> siglock is dropped, and return a dangling ptr.
Understood. The other option is to copy the value out...
Thanks for the helpful review. Rev 2 coming...
> > + return tty;
> > +}
> > +
> > 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);
> > @@ -500,6 +514,10 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
> > {
> > return -1;
> > }
> > +static inline char *audit_get_tty(struct task_struct *tsk)
> > +{
> > + return "(invalid)";
> > +}
> > static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
> > { }
> > static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid,
> > diff --git a/kernel/audit.c b/kernel/audit.c
> > index 3a3e5de..fae11df 100644
> > --- a/kernel/audit.c
> > +++ b/kernel/audit.c
> > @@ -64,7 +64,6 @@
> > #include <linux/security.h>
> > #endif
> > #include <linux/freezer.h>
> > -#include <linux/tty.h>
> > #include <linux/pid_namespace.h>
> > #include <net/netns/generic.h>
> >
> > @@ -1873,7 +1872,6 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
> > {
> > const struct cred *cred;
> > char comm[sizeof(tsk->comm)];
> > - char *tty;
>
> struct tty_struct *tty;
>
> >
> > if (!ab)
> > return;
> > @@ -1881,13 +1879,6 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
> > /* tsk == current */
> > cred = current_cred();
> >
> > - spin_lock_irq(&tsk->sighand->siglock);
> > - if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
> > - tty = tsk->signal->tty->name;
> > - else
> > - tty = "(none)";
> > - spin_unlock_irq(&tsk->sighand->siglock);
>
> tty = get_current_tty();
>
> > -
> > audit_log_format(ab,
> > " ppid=%d pid=%d auid=%u uid=%u gid=%u"
> > " euid=%u suid=%u fsuid=%u"
> > @@ -1903,7 +1894,7 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
> > from_kgid(&init_user_ns, cred->egid),
> > from_kgid(&init_user_ns, cred->sgid),
> > from_kgid(&init_user_ns, cred->fsgid),
> > - tty, audit_get_sessionid(tsk));
> > + audit_get_tty(tsk), audit_get_sessionid(tsk));
>
> tty_name(tty), ....);
> ^^^^^^^^^^
> returns "NULL tty" if tty == NULL
>
> tty_kref_put(tty);
>
>
> >
> > audit_log_format(ab, " comm=");
> > audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index 195ffae..a0467fb 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -1993,8 +1993,9 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
> > return;
> > audit_log_format(ab, "pid=%d uid=%u", task_pid_nr(current), uid);
> > audit_log_task_context(ab);
> > - audit_log_format(ab, " old-auid=%u auid=%u old-ses=%u ses=%u res=%d",
> > - oldloginuid, loginuid, oldsessionid, sessionid, !rc);
>
> tty = get_current_tty();
>
> > + audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
> > + oldloginuid, loginuid, audit_get_tty(current),
>
> ......., tty_name(tty),
>
> > + oldsessionid, sessionid, !rc);
>
> tty_kref_put(tty);
>
> Regards,
> Peter Hurley
>
>
> > audit_log_end(ab);
> > }
> >
> >
>
- RGB
--
Richard Guy Briggs <[email protected]>
Kernel Security Engineering, Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635