cifs: protect access of TCP_Server_Info::{dstaddr,hostname}

Use the appropriate locks to protect access of hostname and dstaddr
fields in cifs_tree_connect() as they might get changed by other
tasks.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/dfs.c b/fs/cifs/dfs.c
index 30086f2..b64d203 100644 (file)
--- a/fs/cifs/dfs.c
+++ b/fs/cifs/dfs.c
@@ -327,8 +327,8 @@ static int update_server_fullpath(struct TCP_Server_Info *server, struct cifs_sb
        return rc;
 }
 
-static int target_share_matches_server(struct TCP_Server_Info *server, const char *tcp_host,
-                                      size_t tcp_host_len, char *share, bool *target_match)
+static int target_share_matches_server(struct TCP_Server_Info *server, char *share,
+                                      bool *target_match)
 {
        int rc = 0;
        const char *dfs_host;
@@ -338,13 +338,16 @@ static int target_share_matches_server(struct TCP_Server_Info *server, const cha
        extract_unc_hostname(share, &dfs_host, &dfs_host_len);
 
        /* Check if hostnames or addresses match */
-       if (dfs_host_len != tcp_host_len || strncasecmp(dfs_host, tcp_host, dfs_host_len) != 0) {
-               cifs_dbg(FYI, "%s: %.*s doesn't match %.*s\n", __func__, (int)dfs_host_len,
-                        dfs_host, (int)tcp_host_len, tcp_host);
+       cifs_server_lock(server);
+       if (dfs_host_len != strlen(server->hostname) ||
+           strncasecmp(dfs_host, server->hostname, dfs_host_len)) {
+               cifs_dbg(FYI, "%s: %.*s doesn't match %s\n", __func__,
+                        (int)dfs_host_len, dfs_host, server->hostname);
                rc = match_target_ip(server, dfs_host, dfs_host_len, target_match);
                if (rc)
                        cifs_dbg(VFS, "%s: failed to match target ip: %d\n", __func__, rc);
        }
+       cifs_server_unlock(server);
        return rc;
 }
 
@@ -358,13 +361,9 @@ static int __tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *t
        struct cifs_ses *root_ses = CIFS_DFS_ROOT_SES(tcon->ses);
        struct cifs_tcon *ipc = root_ses->tcon_ipc;
        char *share = NULL, *prefix = NULL;
-       const char *tcp_host;
-       size_t tcp_host_len;
        struct dfs_cache_tgt_iterator *tit;
        bool target_match;
 
-       extract_unc_hostname(server->hostname, &tcp_host, &tcp_host_len);
-
        tit = dfs_cache_get_tgt_iterator(tl);
        if (!tit) {
                rc = -ENOENT;
@@ -387,8 +386,7 @@ static int __tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *t
                        break;
                }
 
-               rc = target_share_matches_server(server, tcp_host, tcp_host_len, share,
-                                                &target_match);
+               rc = target_share_matches_server(server, share, &target_match);
                if (rc)
                        break;
                if (!target_match) {
@@ -497,7 +495,9 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
        }
 
        if (tcon->ipc) {
+               cifs_server_lock(server);
                scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
+               cifs_server_unlock(server);
                rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
                goto out;
        }

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 4d3c586..2a19c79 100644 (file)
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -1277,7 +1277,9 @@ int match_target_ip(struct TCP_Server_Info *server,
        if (rc < 0)
                return rc;
 
+       spin_lock(&server->srv_lock);
        *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
+       spin_unlock(&server->srv_lock);
        cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
        return 0;
 }