dlm: fix dlm_dir_lookup() handling of too long names

[safe/jmp/linux-2.6] / fs / dlm / dir.c

diff --git a/fs/dlm/dir.c b/fs/dlm/dir.c
index 600bb1d..85defeb 100644 (file)
--- a/fs/dlm/dir.c
+++ b/fs/dlm/dir.c
@@ -220,6 +220,7 @@ int dlm_recover_directory(struct dlm_ls *ls)
                last_len = 0;
 
                for (;;) {
+                       int left;
                        error = dlm_recovery_stopped(ls);
                        if (error)
                                goto out_free;
@@ -235,12 +236,21 @@ int dlm_recover_directory(struct dlm_ls *ls)
                         * pick namelen/name pairs out of received buffer
                         */
 
-                       b = ls->ls_recover_buf + sizeof(struct dlm_rcom);
+                       b = ls->ls_recover_buf->rc_buf;
+                       left = ls->ls_recover_buf->rc_header.h_length;
+                       left -= sizeof(struct dlm_rcom);
 
                        for (;;) {
-                               memcpy(&namelen, b, sizeof(uint16_t));
-                               namelen = be16_to_cpu(namelen);
-                               b += sizeof(uint16_t);
+                               __be16 v;
+
+                               error = -EINVAL;
+                               if (left < sizeof(__be16))
+                                       goto out_free;
+
+                               memcpy(&v, b, sizeof(__be16));
+                               namelen = be16_to_cpu(v);
+                               b += sizeof(__be16);
+                               left -= sizeof(__be16);
 
                                /* namelen of 0xFFFFF marks end of names for
                                   this node; namelen of 0 marks end of the
@@ -251,6 +261,12 @@ int dlm_recover_directory(struct dlm_ls *ls)
                                if (!namelen)
                                        break;
 
+                               if (namelen > left)
+                                       goto out_free;
+
+                               if (namelen > DLM_RESNAME_MAXLEN)
+                                       goto out_free;
+
                                error = -ENOMEM;
                                de = get_free_de(ls, namelen);
                                if (!de)
@@ -262,6 +278,7 @@ int dlm_recover_directory(struct dlm_ls *ls)
                                memcpy(de->name, b, namelen);
                                memcpy(last_name, b, namelen);
                                b += namelen;
+                               left -= namelen;
 
                                add_entry_to_hash(ls, de);
                                count++;
@@ -302,6 +319,9 @@ static int get_entry(struct dlm_ls *ls, int nodeid, char *name,
 
        write_unlock(&ls->ls_dirtbl[bucket].lock);
 
+       if (namelen > DLM_RESNAME_MAXLEN)
+               return -EINVAL;
+
        de = kzalloc(sizeof(struct dlm_direntry) + namelen, GFP_KERNEL);
        if (!de)
                return -ENOMEM;
@@ -329,49 +349,47 @@ int dlm_dir_lookup(struct dlm_ls *ls, int nodeid, char *name, int namelen,
        return get_entry(ls, nodeid, name, namelen, r_nodeid);
 }
 
-/* Copy the names of master rsb's into the buffer provided.
-   Only select names whose dir node is the given nodeid. */
+static struct dlm_rsb *find_rsb_root(struct dlm_ls *ls, char *name, int len)
+{
+       struct dlm_rsb *r;
+
+       down_read(&ls->ls_root_sem);
+       list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
+               if (len == r->res_length && !memcmp(name, r->res_name, len)) {
+                       up_read(&ls->ls_root_sem);
+                       return r;
+               }
+       }
+       up_read(&ls->ls_root_sem);
+       return NULL;
+}
+
+/* Find the rsb where we left off (or start again), then send rsb names
+   for rsb's we're master of and whose directory node matches the requesting
+   node.  inbuf is the rsb name last sent, inlen is the name's length */
 
 void dlm_copy_master_names(struct dlm_ls *ls, char *inbuf, int inlen,
                           char *outbuf, int outlen, int nodeid)
 {
        struct list_head *list;
-       struct dlm_rsb *start_r = NULL, *r = NULL;
-       int offset = 0, start_namelen, error, dir_nodeid;
-       char *start_name;
+       struct dlm_rsb *r;
+       int offset = 0, dir_nodeid;
        uint16_t be_namelen;
 
-       /*
-        * Find the rsb where we left off (or start again)
-        */
-
-       start_namelen = inlen;
-       start_name = inbuf;
-
-       if (start_namelen > 1) {
-               /*
-                * We could also use a find_rsb_root() function here that
-                * searched the ls_root_list.
-                */
-               error = dlm_find_rsb(ls, start_name, start_namelen, R_MASTER,
-                                    &start_r);
-               DLM_ASSERT(!error && start_r,
-                          printk("error %d\n", error););
-               DLM_ASSERT(!list_empty(&start_r->res_root_list),
-                          dlm_print_rsb(start_r););
-               dlm_put_rsb(start_r);
-       }
-
-       /*
-        * Send rsb names for rsb's we're master of and whose directory node
-        * matches the requesting node.
-        */
-
        down_read(&ls->ls_root_sem);
-       if (start_r)
-               list = start_r->res_root_list.next;
-       else
+
+       if (inlen > 1) {
+               r = find_rsb_root(ls, inbuf, inlen);
+               if (!r) {
+                       inbuf[inlen - 1] = '\0';
+                       log_error(ls, "copy_master_names from %d start %d %s",
+                                 nodeid, inlen, inbuf);
+                       goto out;
+               }
+               list = r->res_root_list.next;
+       } else {
                list = ls->ls_root_list.next;
+       }
 
        for (offset = 0; list != &ls->ls_root_list; list = list->next) {
                r = list_entry(list, struct dlm_rsb, res_root_list);