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Subject[PATCH v5 9/9] audit: overhaul __audit_inode_child to accomodate retrying
Date
In order to accomodate retrying path-based syscalls, we need to add a
new "type" argument to audit_inode_child. This will tell us whether
we're looking for a child entry that represents a create or a delete.

If we find a parent, don't automatically assume that we need to create a
new entry. Instead, use the information we have to try to find an
existing entry first. Update it if one is found and create a new one if
not.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
fs/btrfs/ioctl.c | 2 +-
fs/namei.c | 2 +-
include/linux/audit.h | 12 ++++++----
include/linux/fsnotify.h | 8 +++----
kernel/auditsc.c | 57 +++++++++++++++++++++++++-----------------------
5 files changed, 44 insertions(+), 37 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 5c83f4d..903242e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -592,7 +592,7 @@ static int btrfs_may_delete(struct inode *dir,struct dentry *victim,int isdir)
return -ENOENT;

BUG_ON(victim->d_parent->d_inode != dir);
- audit_inode_child(dir, victim);
+ audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);

error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
if (error)
diff --git a/fs/namei.c b/fs/namei.c
index a19af74..08e5045 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2060,7 +2060,7 @@ static int may_delete(struct inode *dir,struct dentry *victim,int isdir)
return -ENOENT;

BUG_ON(victim->d_parent->d_inode != dir);
- audit_inode_child(dir, victim);
+ audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);

error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
if (error)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 2fc6831..7a15359 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -454,6 +454,8 @@ extern int audit_classify_arch(int arch);
#define AUDIT_TYPE_UNKNOWN 0 /* we don't know yet */
#define AUDIT_TYPE_NORMAL 1 /* a "normal" audit record */
#define AUDIT_TYPE_PARENT 2 /* a parent audit record */
+#define AUDIT_TYPE_CHILD_DELETE 3 /* a child being deleted */
+#define AUDIT_TYPE_CHILD_CREATE 4 /* a child being created */

#ifdef CONFIG_AUDITSYSCALL
/* These are defined in auditsc.c */
@@ -469,7 +471,8 @@ extern void audit_putname(const char *name);
extern void __audit_inode(const char *name, const struct dentry *dentry,
unsigned int parent);
extern void __audit_inode_child(const struct inode *parent,
- const struct dentry *dentry);
+ const struct dentry *dentry,
+ const unsigned char type);
extern void __audit_seccomp(unsigned long syscall, long signr, int code);
extern void __audit_ptrace(struct task_struct *t);

@@ -510,9 +513,10 @@ static inline void audit_inode(const char *name, const struct dentry *dentry,
__audit_inode(name, dentry, parent);
}
static inline void audit_inode_child(const struct inode *parent,
- const struct dentry *dentry) {
+ const struct dentry *dentry,
+ const unsigned char type) {
if (unlikely(!audit_dummy_context()))
- __audit_inode_child(parent, dentry);
+ __audit_inode_child(parent, dentry, type);
}
void audit_core_dumps(long signr);

@@ -640,7 +644,7 @@ extern int audit_signals;
#define __audit_inode(n,d,p) do { ; } while (0)
#define __audit_inode_child(p,d) do { ; } while (0)
#define audit_inode(n,d,p) do { (void)(d); } while (0)
-#define audit_inode_child(p,d) do { ; } while (0)
+#define audit_inode_child(p,d,t) do { ; } while (0)
#define audit_core_dumps(i) do { ; } while (0)
#define audit_seccomp(i,s,c) do { ; } while (0)
#define auditsc_get_stamp(c,t,s) (0)
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 9c28471..0fbfb46 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -109,7 +109,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,

if (source)
fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
- audit_inode_child(new_dir, moved);
+ audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
}

/*
@@ -155,7 +155,7 @@ static inline void fsnotify_inoderemove(struct inode *inode)
*/
static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
{
- audit_inode_child(inode, dentry);
+ audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);

fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
}
@@ -168,7 +168,7 @@ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
{
fsnotify_link_count(inode);
- audit_inode_child(dir, new_dentry);
+ audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);

fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, new_dentry->d_name.name, 0);
}
@@ -181,7 +181,7 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
__u32 mask = (FS_CREATE | FS_ISDIR);
struct inode *d_inode = dentry->d_inode;

- audit_inode_child(inode, dentry);
+ audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);

fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
}
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index f4cdefe..bafb618 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2199,6 +2199,7 @@ out:
* __audit_inode_child - collect inode info for created/removed objects
* @parent: inode of dentry parent
* @dentry: dentry being audited
+ * @type: AUDIT_TYPE_* value that we're looking for
*
* For syscalls that create or remove filesystem objects, audit_inode
* can only collect information for the filesystem object's parent.
@@ -2209,13 +2210,13 @@ out:
* unsuccessful attempts.
*/
void __audit_inode_child(const struct inode *parent,
- const struct dentry *dentry)
+ const struct dentry *dentry,
+ const unsigned char type)
{
struct audit_context *context = current->audit_context;
- const char *found_parent = NULL, *found_child = NULL;
const struct inode *inode = dentry->d_inode;
const char *dname = dentry->d_name.name;
- struct audit_names *n;
+ struct audit_names *n, *found_parent = NULL, *found_child = NULL;

if (!context->in_syscall)
return;
@@ -2223,63 +2224,65 @@ void __audit_inode_child(const struct inode *parent,
if (inode)
handle_one(inode);

- /* parent is more likely, look for it first */
+ /* look for a parent entry first */
list_for_each_entry(n, &context->names_list, list) {
- if (!n->name)
+ if (!n->name || n->type != AUDIT_TYPE_PARENT)
continue;

if (n->ino == parent->i_ino &&
!audit_compare_dname_path(dname, n->name, n->name_len)) {
- found_parent = n->name;
- goto add_names;
+ found_parent = n;
+ break;
}
}

- /* no matching parent, look for matching child */
+ /* is there a matching child entry? */
list_for_each_entry(n, &context->names_list, list) {
- if (!n->name)
+ /* can only match entries that have a name */
+ if (!n->name || n->type != type)
+ continue;
+
+ /* if we found a parent, make sure this one is a child of it */
+ if (found_parent && (n->name != found_parent->name))
continue;

- /* strcmp() is the more likely scenario */
if (!strcmp(dname, n->name) ||
!audit_compare_dname_path(dname, n->name,
+ found_parent ?
+ found_parent->name_len :
AUDIT_NAME_FULL)) {
- if (inode)
- audit_copy_inode(n, dentry, inode);
- else
- n->ino = (unsigned long)-1;
- n->type = AUDIT_TYPE_NORMAL;
- found_child = n->name;
- goto add_names;
+ found_child = n;
+ break;
}
}

-add_names:
if (!found_parent) {
- n = audit_alloc_name(context, AUDIT_TYPE_NORMAL);
+ /* create a new, "anonymous" parent record */
+ n = audit_alloc_name(context, AUDIT_TYPE_PARENT);
if (!n)
return;
audit_copy_inode(n, NULL, parent);
}

if (!found_child) {
- n = audit_alloc_name(context, AUDIT_TYPE_NORMAL);
- if (!n)
+ found_child = audit_alloc_name(context, type);
+ if (!found_child)
return;

/* Re-use the name belonging to the slot for a matching parent
* directory. All names for this context are relinquished in
* audit_free_names() */
if (found_parent) {
- n->name = found_parent;
- n->name_len = AUDIT_NAME_FULL;
+ found_child->name = found_parent->name;
+ found_child->name_len = AUDIT_NAME_FULL;
/* don't call __putname() */
- n->name_put = false;
+ found_child->name_put = false;
}
-
- if (inode)
- audit_copy_inode(n, dentry, inode);
}
+ if (inode)
+ audit_copy_inode(found_child, dentry, inode);
+ else
+ found_child->ino = (unsigned long)-1;
}
EXPORT_SYMBOL_GPL(__audit_inode_child);

--
1.7.11.2


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