1 files changed, 220 insertions, 1 deletions

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 8a85c203be12..80ecab0942ef 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -65,6 +65,7 @@
 #include <linux/binfmts.h>
 #include <linux/highmem.h>
 #include <linux/syscalls.h>
+#include <linux/inotify.h>
 
 #include "audit.h"
 
@@ -179,6 +180,11 @@ struct audit_aux_data_pids {
         int                     pid_count;
 };
 
+struct audit_tree_refs {
+        struct audit_tree_refs *next;
+        struct audit_chunk *c[31];
+};
+
 /* The per-task audit context. */
 struct audit_context {
         int                 dummy;      /* must be the first element */
@@ -211,6 +217,9 @@ struct audit_context {
         pid_t               target_pid;
         u32                 target_sid;
 
+        struct audit_tree_refs *trees, *first_trees;
+        int tree_count;
+
 #if AUDIT_DEBUG
         int                 put_count;
         int                 ino_count;
@@ -265,6 +274,117 @@ static int audit_match_perm(struct audit_context *ctx, int mask)
         }
 }
 
+/*
+ * We keep a linked list of fixed-sized (31 pointer) arrays of audit_chunk *;
+ * ->first_trees points to its beginning, ->trees - to the current end of data.
+ * ->tree_count is the number of free entries in array pointed to by ->trees.
+ * Original condition is (NULL, NULL, 0); as soon as it grows we never revert to NULL,
+ * "empty" becomes (p, p, 31) afterwards.  We don't shrink the list (and seriously,
+ * it's going to remain 1-element for almost any setup) until we free context itself.
+ * References in it _are_ dropped - at the same time we free/drop aux stuff.
+ */
+
+#ifdef CONFIG_AUDIT_TREE
+static int put_tree_ref(struct audit_context *ctx, struct audit_chunk *chunk)
+{
+        struct audit_tree_refs *p = ctx->trees;
+        int left = ctx->tree_count;
+        if (likely(left)) {
+                p->c[--left] = chunk;
+                ctx->tree_count = left;
+                return 1;
+        }
+        if (!p)
+                return 0;
+        p = p->next;
+        if (p) {
+                p->c[30] = chunk;
+                ctx->trees = p;
+                ctx->tree_count = 30;
+                return 1;
+        }
+        return 0;
+}
+
+static int grow_tree_refs(struct audit_context *ctx)
+{
+        struct audit_tree_refs *p = ctx->trees;
+        ctx->trees = kzalloc(sizeof(struct audit_tree_refs), GFP_KERNEL);
+        if (!ctx->trees) {
+                ctx->trees = p;
+                return 0;
+        }
+        if (p)
+                p->next = ctx->trees;
+        else
+                ctx->first_trees = ctx->trees;
+        ctx->tree_count = 31;
+        return 1;
+}
+#endif
+
+static void unroll_tree_refs(struct audit_context *ctx,
+                      struct audit_tree_refs *p, int count)
+{
+#ifdef CONFIG_AUDIT_TREE
+        struct audit_tree_refs *q;
+        int n;
+        if (!p) {
+                /* we started with empty chain */
+                p = ctx->first_trees;
+                count = 31;
+                /* if the very first allocation has failed, nothing to do */
+                if (!p)
+                        return;
+        }
+        n = count;
+        for (q = p; q != ctx->trees; q = q->next, n = 31) {
+                while (n--) {
+                        audit_put_chunk(q->c[n]);
+                        q->c[n] = NULL;
+                }
+        }
+        while (n-- > ctx->tree_count) {
+                audit_put_chunk(q->c[n]);
+                q->c[n] = NULL;
+        }
+        ctx->trees = p;
+        ctx->tree_count = count;
+#endif
+}
+
+static void free_tree_refs(struct audit_context *ctx)
+{
+        struct audit_tree_refs *p, *q;
+        for (p = ctx->first_trees; p; p = q) {
+                q = p->next;
+                kfree(p);
+        }
+}
+
+static int match_tree_refs(struct audit_context *ctx, struct audit_tree *tree)
+{
+#ifdef CONFIG_AUDIT_TREE
+        struct audit_tree_refs *p;
+        int n;
+        if (!tree)
+                return 0;
+        /* full ones */
+        for (p = ctx->first_trees; p != ctx->trees; p = p->next) {
+                for (n = 0; n < 31; n++)
+                        if (audit_tree_match(p->c[n], tree))
+                                return 1;
+        }
+        /* partial */
+        if (p) {
+                for (n = ctx->tree_count; n < 31; n++)
+                        if (audit_tree_match(p->c[n], tree))
+                                return 1;
+        }
+#endif
+        return 0;
+}
+
 /* Determine if any context name data matches a rule's watch data */
 /* Compare a task_struct with an audit_rule.  Return 1 on match, 0
  * otherwise. */
@@ -379,6 +499,10 @@ static int audit_filter_rules(struct task_struct *tsk,
                                 result = (name->dev == rule->watch->dev &&
                                           name->ino == rule->watch->ino);
                         break;
+                case AUDIT_DIR:
+                        if (ctx)
+                                result = match_tree_refs(ctx, rule->tree);
+                        break;
                 case AUDIT_LOGINUID:
                         result = 0;
                         if (ctx)
@@ -727,6 +851,8 @@ static inline void audit_free_context(struct audit_context *context)
                                context->name_count, count);
                 }
                 audit_free_names(context);
+                unroll_tree_refs(context, NULL, 0);
+                free_tree_refs(context);
                 audit_free_aux(context);
                 kfree(context->filterkey);
                 kfree(context);
@@ -1270,6 +1396,7 @@ void audit_syscall_exit(int valid, long return_code)
                 tsk->audit_context = new_context;
         } else {
                 audit_free_names(context);
+                unroll_tree_refs(context, NULL, 0);
                 audit_free_aux(context);
                 context->aux = NULL;
                 context->aux_pids = NULL;
@@ -1281,6 +1408,95 @@ void audit_syscall_exit(int valid, long return_code)
         }
 }
 
+static inline void handle_one(const struct inode *inode)
+{
+#ifdef CONFIG_AUDIT_TREE
+        struct audit_context *context;
+        struct audit_tree_refs *p;
+        struct audit_chunk *chunk;
+        int count;
+        if (likely(list_empty(&inode->inotify_watches)))
+                return;
+        context = current->audit_context;
+        p = context->trees;
+        count = context->tree_count;
+        rcu_read_lock();
+        chunk = audit_tree_lookup(inode);
+        rcu_read_unlock();
+        if (!chunk)
+                return;
+        if (likely(put_tree_ref(context, chunk)))
+                return;
+        if (unlikely(!grow_tree_refs(context))) {
+                printk(KERN_WARNING "out of memory, audit has lost a tree reference");
+                audit_set_auditable(context);
+                audit_put_chunk(chunk);
+                unroll_tree_refs(context, p, count);
+                return;
+        }
+        put_tree_ref(context, chunk);
+#endif
+}
+
+static void handle_path(const struct dentry *dentry)
+{
+#ifdef CONFIG_AUDIT_TREE
+        struct audit_context *context;
+        struct audit_tree_refs *p;
+        const struct dentry *d, *parent;
+        struct audit_chunk *drop;
+        unsigned long seq;
+        int count;
+
+        context = current->audit_context;
+        p = context->trees;
+        count = context->tree_count;
+retry:
+        drop = NULL;
+        d = dentry;
+        rcu_read_lock();
+        seq = read_seqbegin(&rename_lock);
+        for(;;) {
+                struct inode *inode = d->d_inode;
+                if (inode && unlikely(!list_empty(&inode->inotify_watches))) {
+                        struct audit_chunk *chunk;
+                        chunk = audit_tree_lookup(inode);
+                        if (chunk) {
+                                if (unlikely(!put_tree_ref(context, chunk))) {
+                                        drop = chunk;
+                                        break;
+                                }
+                        }
+                }
+                parent = d->d_parent;
+                if (parent == d)
+                        break;
+                d = parent;
+        }
+        if (unlikely(read_seqretry(&rename_lock, seq) || drop)) {  /* in this order */
+                rcu_read_unlock();
+                if (!drop) {
+                        /* just a race with rename */
+                        unroll_tree_refs(context, p, count);
+                        goto retry;
+                }
+                audit_put_chunk(drop);
+                if (grow_tree_refs(context)) {
+                        /* OK, got more space */
+                        unroll_tree_refs(context, p, count);
+                        goto retry;
+                }
+                /* too bad */
+                printk(KERN_WARNING
+                        "out of memory, audit has lost a tree reference");
+                unroll_tree_refs(context, p, count);
+                audit_set_auditable(context);
+                return;
+        }
+        rcu_read_unlock();
+#endif
+}
+
 /**
  * audit_getname - add a name to the list
  * @name: name to add
@@ -1407,7 +1623,7 @@ void __audit_inode(const char *name, const struct dentry *dentry)
 {
         int idx;
         struct audit_context *context = current->audit_context;
-        const struct inode *inode = inode = dentry->d_inode;
+        const struct inode *inode = dentry->d_inode;
 
         if (!context->in_syscall)
                 return;
@@ -1427,6 +1643,7 @@ void __audit_inode(const char *name, const struct dentry *dentry)
                 idx = context->name_count - 1;
                 context->names[idx].name = NULL;
         }
+        handle_path(dentry);
         audit_copy_inode(&context->names[idx], inode);
 }
 
@@ -1456,6 +1673,8 @@ void __audit_inode_child(const char *dname, const struct dentry *dentry,
         if (!context->in_syscall)
                 return;
 
+        if (inode)
+                handle_one(inode);
         /* determine matching parent */
         if (!dname)
                 goto add_names;