3 files changed, 55 insertions, 25 deletions

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 9da6420e2056..1d027e29ce8d 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -471,6 +471,7 @@ static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
  * @avd: access vector decisions
  * @result: result from avc_has_perm_noaudit
  * @a:  auxiliary audit data
+ * @flags: VFS walk flags
  *
  * Audit the granting or denial of permissions in accordance
  * with the policy.  This function is typically called by
@@ -481,9 +482,10 @@ static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
  * be performed under a lock, to allow the lock to be released
  * before calling the auditing code.
  */
-void avc_audit(u32 ssid, u32 tsid,
+int avc_audit(u32 ssid, u32 tsid,
                u16 tclass, u32 requested,
-               struct av_decision *avd, int result, struct common_audit_data *a)
+               struct av_decision *avd, int result, struct common_audit_data *a,
+               unsigned flags)
 {
         struct common_audit_data stack_data;
         u32 denied, audited;
@@ -515,11 +517,24 @@ void avc_audit(u32 ssid, u32 tsid,
         else
                 audited = requested & avd->auditallow;
         if (!audited)
-                return;
+                return 0;
+
         if (!a) {
                 a = &stack_data;
                 COMMON_AUDIT_DATA_INIT(a, NONE);
         }
+
+        /*
+         * When in a RCU walk do the audit on the RCU retry.  This is because
+         * the collection of the dname in an inode audit message is not RCU
+         * safe.  Note this may drop some audits when the situation changes
+         * during retry. However this is logically just as if the operation
+         * happened a little later.
+         */
+        if ((a->type == LSM_AUDIT_DATA_FS) &&
+            (flags & IPERM_FLAG_RCU))
+                return -ECHILD;
+
         a->selinux_audit_data.tclass = tclass;
         a->selinux_audit_data.requested = requested;
         a->selinux_audit_data.ssid = ssid;
@@ -529,6 +544,7 @@ void avc_audit(u32 ssid, u32 tsid,
         a->lsm_pre_audit = avc_audit_pre_callback;
         a->lsm_post_audit = avc_audit_post_callback;
         common_lsm_audit(a);
+        return 0;
 }
 
 /**
@@ -793,6 +809,7 @@ int avc_has_perm_noaudit(u32 ssid, u32 tsid,
  * @tclass: target security class
  * @requested: requested permissions, interpreted based on @tclass
  * @auditdata: auxiliary audit data
+ * @flags: VFS walk flags
  *
  * Check the AVC to determine whether the @requested permissions are granted
  * for the SID pair (@ssid, @tsid), interpreting the permissions
@@ -802,14 +819,19 @@ int avc_has_perm_noaudit(u32 ssid, u32 tsid,
  * permissions are granted, -%EACCES if any permissions are denied, or
  * another -errno upon other errors.
  */
-int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
-                 u32 requested, struct common_audit_data *auditdata)
+int avc_has_perm_flags(u32 ssid, u32 tsid, u16 tclass,
+                       u32 requested, struct common_audit_data *auditdata,
+                       unsigned flags)
 {
         struct av_decision avd;
-        int rc;
+        int rc, rc2;
 
         rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, 0, &avd);
-        avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata);
+
+        rc2 = avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata,
+                        flags);
+        if (rc2)
+                return rc2;
         return rc;
 }
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 9a220be17a3f..ed5f29aa0a38 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1447,8 +1447,11 @@ static int task_has_capability(struct task_struct *tsk,
         }
 
         rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);
-        if (audit == SECURITY_CAP_AUDIT)
-                avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
+        if (audit == SECURITY_CAP_AUDIT) {
+                int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad, 0);
+                if (rc2)
+                        return rc2;
+        }
         return rc;
 }
 
@@ -1468,7 +1471,8 @@ static int task_has_system(struct task_struct *tsk,
 static int inode_has_perm(const struct cred *cred,
                           struct inode *inode,
                           u32 perms,
-                          struct common_audit_data *adp)
+                          struct common_audit_data *adp,
+                          unsigned flags)
 {
         struct inode_security_struct *isec;
         struct common_audit_data ad;
@@ -1488,7 +1492,7 @@ static int inode_has_perm(const struct cred *cred,
                 ad.u.fs.inode = inode;
         }
 
-        return avc_has_perm(sid, isec->sid, isec->sclass, perms, adp);
+        return avc_has_perm_flags(sid, isec->sid, isec->sclass, perms, adp, flags);
 }
 
 /* Same as inode_has_perm, but pass explicit audit data containing
@@ -1505,7 +1509,7 @@ static inline int dentry_has_perm(const struct cred *cred,
         COMMON_AUDIT_DATA_INIT(&ad, FS);
         ad.u.fs.path.mnt = mnt;
         ad.u.fs.path.dentry = dentry;
-        return inode_has_perm(cred, inode, av, &ad);
+        return inode_has_perm(cred, inode, av, &ad, 0);
 }
 
 /* Check whether a task can use an open file descriptor to
@@ -1541,7 +1545,7 @@ static int file_has_perm(const struct cred *cred,
         /* av is zero if only checking access to the descriptor. */
         rc = 0;
         if (av)
-                rc = inode_has_perm(cred, inode, av, &ad);
+                rc = inode_has_perm(cred, inode, av, &ad, 0);
 
 out:
         return rc;
@@ -2103,7 +2107,7 @@ static inline void flush_unauthorized_files(const struct cred *cred,
                         file = file_priv->file;
                         inode = file->f_path.dentry->d_inode;
                         if (inode_has_perm(cred, inode,
-                                           FILE__READ | FILE__WRITE, NULL)) {
+                                           FILE__READ | FILE__WRITE, NULL, 0)) {
                                 drop_tty = 1;
                         }
                 }
@@ -2649,10 +2653,6 @@ static int selinux_inode_permission(struct inode *inode, int mask, unsigned flag
         if (!mask)
                 return 0;
 
-        /* May be droppable after audit */
-        if (flags & IPERM_FLAG_RCU)
-                return -ECHILD;
-
         COMMON_AUDIT_DATA_INIT(&ad, FS);
         ad.u.fs.inode = inode;
 
@@ -2661,7 +2661,7 @@ static int selinux_inode_permission(struct inode *inode, int mask, unsigned flag
 
         perms = file_mask_to_av(inode->i_mode, mask);
 
-        return inode_has_perm(cred, inode, perms, &ad);
+        return inode_has_perm(cred, inode, perms, &ad, flags);
 }
 
 static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
@@ -3208,7 +3208,7 @@ static int selinux_dentry_open(struct file *file, const struct cred *cred)
          * new inode label or new policy.
          * This check is not redundant - do not remove.
          */
-        return inode_has_perm(cred, inode, open_file_to_av(file), NULL);
+        return inode_has_perm(cred, inode, open_file_to_av(file), NULL, 0);
 }
 
 /* task security operations */
diff --git a/security/selinux/include/avc.h b/security/selinux/include/avc.h
index 5615081b73ec..e77b2ac2908b 100644
--- a/security/selinux/include/avc.h
+++ b/security/selinux/include/avc.h
@@ -54,11 +54,11 @@ struct avc_cache_stats {
 
 void __init avc_init(void);
 
-void avc_audit(u32 ssid, u32 tsid,
+int avc_audit(u32 ssid, u32 tsid,
                u16 tclass, u32 requested,
                struct av_decision *avd,
                int result,
-               struct common_audit_data *a);
+              struct common_audit_data *a, unsigned flags);
 
 #define AVC_STRICT 1 /* Ignore permissive mode. */
 int avc_has_perm_noaudit(u32 ssid, u32 tsid,
@@ -66,9 +66,17 @@ int avc_has_perm_noaudit(u32 ssid, u32 tsid,
                          unsigned flags,
                          struct av_decision *avd);
 
-int avc_has_perm(u32 ssid, u32 tsid,
-                 u16 tclass, u32 requested,
-                 struct common_audit_data *auditdata);
+int avc_has_perm_flags(u32 ssid, u32 tsid,
+                       u16 tclass, u32 requested,
+                       struct common_audit_data *auditdata,
+                       unsigned);
+
+static inline int avc_has_perm(u32 ssid, u32 tsid,
+                               u16 tclass, u32 requested,
+                               struct common_audit_data *auditdata)
+{
+        return avc_has_perm_flags(ssid, tsid, tclass, requested, auditdata, 0);
+}
 
 u32 avc_policy_seqno(void);