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audit: overhaul __audit_inode_child to accomodate retrying

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.

Jeff Layton committed 14 years ago

Commit 4fa6b5e1 parent e3d6b075 files · +47 −38Browse files

Showing the changes to kernel (1 of 5 files). Show all

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kernel/auditsc.c+30−27
@@ -2189,6 +2189,7 @@ out: · 2188 unmodified lines
21892189 * __audit_inode_child - collect inode info for created/removed objects
21902190 * @parent: inode of dentry parent
21912191 * @dentry: dentry being audited
2192+ * @type: AUDIT_TYPE_* value that we're looking for
21922193 *
21932194 * For syscalls that create or remove filesystem objects, audit_inode
21942195 * can only collect information for the filesystem object's parent.
@@ -2199,13 +2200,13 @@ out: · 4 unmodified lines
21992200 * unsuccessful attempts.
22002201 */
22012202 void __audit_inode_child(const struct inode *parent,
2202− const struct dentry *dentry)
2203+ const struct dentry *dentry,
2204+ const unsigned char type)
22032205 {
22042206 struct audit_context *context = current->audit_context;
2205− const char *found_parent = NULL, *found_child = NULL;
22062207 const struct inode *inode = dentry->d_inode;
22072208 const char *dname = dentry->d_name.name;
2208− struct audit_names *n;
2209+ struct audit_names *n, *found_parent = NULL, *found_child = NULL;
22092210
22102211 if (!context->in_syscall)
22112212 return;
@@ -2213,63 +2214,65 @@ void __audit_inode_child(const struct inode *parent, · 1 unmodified line
22132214 if (inode)
22142215 handle_one(inode);
22152216
2216− /* parent is more likely, look for it first */
2217+ /* look for a parent entry first */
22172218 list_for_each_entry(n, &context->names_list, list) {
2218− if (!n->name)
2219+ if (!n->name || n->type != AUDIT_TYPE_PARENT)
22192220 continue;
22202221
22212222 if (n->ino == parent->i_ino &&
22222223 !audit_compare_dname_path(dname, n->name, n->name_len)) {
2223− found_parent = n->name;
2224− goto add_names;
2224+ found_parent = n;
2225+ break;
22252226 }
22262227 }
22272228
2228− /* no matching parent, look for matching child */
2229+ /* is there a matching child entry? */
22292230 list_for_each_entry(n, &context->names_list, list) {
2230− if (!n->name)
2231+ /* can only match entries that have a name */
2232+ if (!n->name || n->type != type)
2233+ continue;
2234+
2235+ /* if we found a parent, make sure this one is a child of it */
2236+ if (found_parent && (n->name != found_parent->name))
22312237 continue;
22322238
2233− /* strcmp() is the more likely scenario */
22342239 if (!strcmp(dname, n->name) ||
22352240 !audit_compare_dname_path(dname, n->name,
2241+ found_parent ?
2242+ found_parent->name_len :
22362243 AUDIT_NAME_FULL)) {
2237− if (inode)
2238− audit_copy_inode(n, dentry, inode);
2239− else
2240− n->ino = (unsigned long)-1;
2241− n->type = AUDIT_TYPE_NORMAL;
2242− found_child = n->name;
2243− goto add_names;
2244+ found_child = n;
2245+ break;
22442246 }
22452247 }
22462248
2247−add_names:
22482249 if (!found_parent) {
2249− n = audit_alloc_name(context, AUDIT_TYPE_NORMAL);
2250+ /* create a new, "anonymous" parent record */
2251+ n = audit_alloc_name(context, AUDIT_TYPE_PARENT);
22502252 if (!n)
22512253 return;
22522254 audit_copy_inode(n, NULL, parent);
22532255 }
22542256
22552257 if (!found_child) {
2256− n = audit_alloc_name(context, AUDIT_TYPE_NORMAL);
2257− if (!n)
2258+ found_child = audit_alloc_name(context, type);
2259+ if (!found_child)
22582260 return;
22592261
22602262 /* Re-use the name belonging to the slot for a matching parent
22612263 * directory. All names for this context are relinquished in
22622264 * audit_free_names() */
22632265 if (found_parent) {
2264− n->name = found_parent;
2265− n->name_len = AUDIT_NAME_FULL;
2266+ found_child->name = found_parent->name;
2267+ found_child->name_len = AUDIT_NAME_FULL;
22662268 /* don't call __putname() */
2267− n->name_put = false;
2269+ found_child->name_put = false;
22682270 }
2269−
2270− if (inode)
2271− audit_copy_inode(n, dentry, inode);
22722271 }
2272+ if (inode)
2273+ audit_copy_inode(found_child, dentry, inode);
2274+ else
2275+ found_child->ino = (unsigned long)-1;
22732276 }
22742277 EXPORT_SYMBOL_GPL(__audit_inode_child);
22752278