[PATCH v7 09/49] audit: optimize audit_compare_dname_path

Jeff Layton
2012-10-02T00:17:18Z

In the cases where we already know the length of the parent, pass it as
a parm so we don't need to recompute it. In the cases where we don't
know the length, pass in AUDIT_NAME_FULL (-1) to indicate that it should
be determined.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
kernel/audit.h | 5 ++++-
kernel/audit_watch.c | 3 ++-
kernel/auditfilter.c | 16 +++++++++++-----
kernel/auditsc.c | 8 +++-----
4 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/kernel/audit.h b/kernel/audit.h
index ee31316..34af33c 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -74,10 +74,13 @@ static inline int audit_hash_ino(u32 ino)
return (ino & (AUDIT_INODE_BUCKETS-1));
}

+/* Indicates that audit should log the full pathname. */
+#define AUDIT_NAME_FULL -1
+
extern int audit_match_class(int class, unsigned syscall);
extern int audit_comparator(const u32 left, const u32 op, const u32 right);
extern int parent_len(const char *path);
-extern int audit_compare_dname_path(const char *dname, const char *path);
+extern int audit_compare_dname_path(const char *dname, const char *path, int plen);
extern struct sk_buff * audit_make_reply(int pid, int seq, int type,
int done, int multi,
const void *payload, int size);
diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index b6a873a..f8e9353 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -265,7 +265,8 @@ static void audit_update_watch(struct audit_parent *parent,
/* Run all of the watches on this parent looking for the one that
* matches the given dname */
list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
- if (audit_compare_dname_path(dname, owatch->path))
+ if (audit_compare_dname_path(dname, owatch->path,
+ AUDIT_NAME_FULL))
continue;

/* If the update involves invalidating rules, do the inode-based
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index f47ba18..1e0899d 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1228,11 +1228,17 @@ int parent_len(const char *path)
return p - path;
}

-/* Compare given dentry name with last component in given path,
- * return of 0 indicates a match. */
-int audit_compare_dname_path(const char *dname, const char *path)
+/**
+ * audit_compare_dname_path - compare given dentry name with last component in
+ * given path. Return of 0 indicates a match.
+ * @dname: dentry name that we're comparing
+ * @path: full pathname that we're comparing
+ * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL
+ * here indicates that we must compute this value.
+ */
+int audit_compare_dname_path(const char *dname, const char *path, int parentlen)
{
- int dlen, pathlen, parentlen;
+ int dlen, pathlen;
const char *p;

dlen = strlen(dname);
@@ -1240,7 +1246,7 @@ int audit_compare_dname_path(const char *dname, const char *path)
if (pathlen < dlen)
return 1;

- parentlen = parent_len(path);
+ parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen;
if (pathlen - parentlen != dlen)
return 1;

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index b03ef6a..52d1f0f 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -81,9 +81,6 @@
* a name dynamically and also add those to the list anchored by names_list. */
#define AUDIT_NAMES 5

-/* Indicates that audit should log the full pathname. */
-#define AUDIT_NAME_FULL -1
-
/* no execve audit message should be longer than this (userspace limits) */
#define MAX_EXECVE_AUDIT_LEN 7500

@@ -2236,7 +2233,7 @@ void __audit_inode_child(const struct inode *parent,
continue;

if (n->ino == parent->i_ino &&
- !audit_compare_dname_path(dname, n->name)) {
+ !audit_compare_dname_path(dname, n->name, n->name_len)) {
found_parent = n->name;
goto add_names;
}
@@ -2249,7 +2246,8 @@ void __audit_inode_child(const struct inode *parent,

/* strcmp() is the more likely scenario */
if (!strcmp(dname, n->name) ||
- !audit_compare_dname_path(dname, n->name)) {
+ !audit_compare_dname_path(dname, n->name,
+ AUDIT_NAME_FULL)) {
if (inode)
audit_copy_inode(n, dentry, inode);
else
--
1.7.11.4