9:53 a.m.
Selinux folks had been complaining about the lack of AVC_PATH
records when audit is disabled. I must admit my stupidity - I assumed
that avc_audit() really couldn't use audit_log_d_path() because of
deadlocks (== could be called with dcache_lock or vfsmount_lock held).
Shouldn't have made that assumption - it never gets called that way.
It _is_ called under spinlocks, but not those.
Since audit_log_d_path() uses ab->gfp_mask for allocations, kmalloc()
in there is not a problem. IOW, the simple fix should be sufficient: let's
rip AUDIT_AVC_PATH out and simply generate pathname as part of main record.
It's trivial to do. Patch below is against the mainline, rhel5 variant
is also trivial.
Comments?
diff --git a/include/linux/audit.h b/include/linux/audit.h
index fccc6e5..f3d6e5f 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -399,7 +399,6 @@ extern int audit_bprm(struct linux_binprm *bprm);
extern int audit_socketcall(int nargs, unsigned long *args);
extern int audit_sockaddr(int len, void *addr);
extern int __audit_fd_pair(int fd1, int fd2);
-extern int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt);
extern int audit_set_macxattr(const char *name);
extern int __audit_mq_open(int oflag, mode_t mode, struct mq_attr __user *u_attr);
extern int __audit_mq_timedsend(mqd_t mqdes, size_t msg_len, unsigned int msg_prio, const
struct timespec __user *u_abs_timeout);
@@ -479,7 +478,6 @@ extern int audit_signals;
#define audit_socketcall(n,a) ({ 0; })
#define audit_fd_pair(n,a) ({ 0; })
#define audit_sockaddr(len, addr) ({ 0; })
-#define audit_avc_path(dentry, mnt) ({ 0; })
#define audit_set_macxattr(n) do { ; } while (0)
#define audit_mq_open(o,m,a) ({ 0; })
#define audit_mq_timedsend(d,l,p,t) ({ 0; })
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index e36481e..10e0e6e 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -176,12 +176,6 @@ struct audit_aux_data_fd_pair {
int fd[2];
};
-struct audit_aux_data_path {
- struct audit_aux_data d;
- struct dentry *dentry;
- struct vfsmount *mnt;
-};
-
struct audit_aux_data_pids {
struct audit_aux_data d;
pid_t target_pid[AUDIT_AUX_PIDS];
@@ -657,12 +651,6 @@ static inline void audit_free_aux(struct audit_context *context)
struct audit_aux_data *aux;
while ((aux = context->aux)) {
- if (aux->type == AUDIT_AVC_PATH) {
- struct audit_aux_data_path *axi = (void *)aux;
- dput(axi->dentry);
- mntput(axi->mnt);
- }
-
context->aux = aux->next;
kfree(aux);
}
@@ -998,11 +986,6 @@ static void audit_log_exit(struct audit_context *context, struct
task_struct *ts
audit_log_hex(ab, axs->a, axs->len);
break; }
- case AUDIT_AVC_PATH: {
- struct audit_aux_data_path *axi = (void *)aux;
- audit_log_d_path(ab, "path=", axi->dentry, axi->mnt);
- break; }
-
case AUDIT_FD_PAIR: {
struct audit_aux_data_fd_pair *axs = (void *)aux;
audit_log_format(ab, "fd0=%d fd1=%d", axs->fd[0], axs->fd[1]);
@@ -1952,36 +1935,6 @@ void __audit_ptrace(struct task_struct *t)
}
/**
- * audit_avc_path - record the granting or denial of permissions
- * @dentry: dentry to record
- * @mnt: mnt to record
- *
- * Returns 0 for success or NULL context or < 0 on error.
- *
- * Called from security/selinux/avc.c::avc_audit()
- */
-int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt)
-{
- struct audit_aux_data_path *ax;
- struct audit_context *context = current->audit_context;
-
- if (likely(!context))
- return 0;
-
- ax = kmalloc(sizeof(*ax), GFP_ATOMIC);
- if (!ax)
- return -ENOMEM;
-
- ax->dentry = dget(dentry);
- ax->mnt = mntget(mnt);
-
- ax->d.type = AUDIT_AVC_PATH;
- ax->d.next = context->aux;
- context->aux = (void *)ax;
- return 0;
-}
-
-/**
* audit_signal_info - record signal info for shutting down audit subsystem
* @sig: signal value
* @t: task being signaled
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index e4396a8..2f4c2bb 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -570,10 +570,12 @@ void avc_audit(u32 ssid, u32 tsid,
case AVC_AUDIT_DATA_FS:
if (a->u.fs.dentry) {
struct dentry *dentry = a->u.fs.dentry;
- if (a->u.fs.mnt)
- audit_avc_path(dentry, a->u.fs.mnt);
- audit_log_format(ab, " name=");
- audit_log_untrustedstring(ab, dentry->d_name.name);
+ if (a->u.fs.mnt) {
+ audit_log_d_path(ab, "path=", dentry, a->u.fs.mnt);
+ } else {
+ audit_log_format(ab, " name=");
+ audit_log_untrustedstring(ab, dentry->d_name.name);
+ }
inode = dentry->d_inode;
} else if (a->u.fs.inode) {
struct dentry *dentry;
@@ -624,9 +626,8 @@ void avc_audit(u32 ssid, u32 tsid,
case AF_UNIX:
u = unix_sk(sk);
if (u->dentry) {
- audit_avc_path(u->dentry, u->mnt);
- audit_log_format(ab, " name=");
- audit_log_untrustedstring(ab, u->dentry->d_name.name);
+ audit_log_d_path(ab, "path=",
+ u->dentry, u->mnt);
break;
}
if (!u->addr)