[ Upstream commit 2b57a4322b1b14348940744fdc02f9a86cbbdbeb ]
Since commit 74d7970febf7 ("ksmbd: fix racy issue from using ->d_parent and ->d_name"), ksmbd can not lookup cross mount points. If last component is a cross mount point during path lookup, check if it is crossed to follow it down. And allow path lookup to cross a mount point when a crossmnt parameter is set to 'yes' in smb.conf.
Cc: stable@vger.kernel.org Fixes: 74d7970febf7 ("ksmbd: fix racy issue from using ->d_parent and ->d_name") Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com --- fs/smb/server/ksmbd_netlink.h | 3 +- fs/smb/server/smb2pdu.c | 27 +++++++++------- fs/smb/server/vfs.c | 58 ++++++++++++++++++++--------------- fs/smb/server/vfs.h | 4 +-- 4 files changed, 53 insertions(+), 39 deletions(-)
diff --git a/fs/smb/server/ksmbd_netlink.h b/fs/smb/server/ksmbd_netlink.h index fb8b2d566efb..b7521e41402e 100644 --- a/fs/smb/server/ksmbd_netlink.h +++ b/fs/smb/server/ksmbd_netlink.h @@ -352,7 +352,8 @@ enum KSMBD_TREE_CONN_STATUS { #define KSMBD_SHARE_FLAG_STREAMS BIT(11) #define KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS BIT(12) #define KSMBD_SHARE_FLAG_ACL_XATTR BIT(13) -#define KSMBD_SHARE_FLAG_UPDATE BIT(14) +#define KSMBD_SHARE_FLAG_UPDATE BIT(14) +#define KSMBD_SHARE_FLAG_CROSSMNT BIT(15)
/* * Tree connect request flags. diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 10d51256858f..687e59cb0c8c 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -2475,8 +2475,9 @@ static void smb2_update_xattrs(struct ksmbd_tree_connect *tcon, } }
-static int smb2_creat(struct ksmbd_work *work, struct path *path, char *name, - int open_flags, umode_t posix_mode, bool is_dir) +static int smb2_creat(struct ksmbd_work *work, struct path *parent_path, + struct path *path, char *name, int open_flags, + umode_t posix_mode, bool is_dir) { struct ksmbd_tree_connect *tcon = work->tcon; struct ksmbd_share_config *share = tcon->share_conf; @@ -2503,7 +2504,7 @@ static int smb2_creat(struct ksmbd_work *work, struct path *path, char *name, return rc; }
- rc = ksmbd_vfs_kern_path_locked(work, name, 0, path, 0); + rc = ksmbd_vfs_kern_path_locked(work, name, 0, parent_path, path, 0); if (rc) { pr_err("cannot get linux path (%s), err = %d\n", name, rc); @@ -2573,7 +2574,7 @@ int smb2_open(struct ksmbd_work *work) struct ksmbd_tree_connect *tcon = work->tcon; struct smb2_create_req *req; struct smb2_create_rsp *rsp; - struct path path; + struct path path, parent_path; struct ksmbd_share_config *share = tcon->share_conf; struct ksmbd_file *fp = NULL; struct file *filp = NULL; @@ -2794,7 +2795,8 @@ int smb2_open(struct ksmbd_work *work) goto err_out1; }
- rc = ksmbd_vfs_kern_path_locked(work, name, LOOKUP_NO_SYMLINKS, &path, 1); + rc = ksmbd_vfs_kern_path_locked(work, name, LOOKUP_NO_SYMLINKS, + &parent_path, &path, 1); if (!rc) { file_present = true;
@@ -2914,7 +2916,8 @@ int smb2_open(struct ksmbd_work *work)
/*create file if not present */ if (!file_present) { - rc = smb2_creat(work, &path, name, open_flags, posix_mode, + rc = smb2_creat(work, &parent_path, &path, name, open_flags, + posix_mode, req->CreateOptions & FILE_DIRECTORY_FILE_LE); if (rc) { if (rc == -ENOENT) { @@ -3329,8 +3332,9 @@ int smb2_open(struct ksmbd_work *work)
err_out: if (file_present || created) { - inode_unlock(d_inode(path.dentry->d_parent)); - dput(path.dentry); + inode_unlock(d_inode(parent_path.dentry)); + path_put(&path); + path_put(&parent_path); } ksmbd_revert_fsids(work); err_out1: @@ -5553,7 +5557,7 @@ static int smb2_create_link(struct ksmbd_work *work, struct nls_table *local_nls) { char *link_name = NULL, *target_name = NULL, *pathname = NULL; - struct path path; + struct path path, parent_path; bool file_present = false; int rc;
@@ -5583,7 +5587,7 @@ static int smb2_create_link(struct ksmbd_work *work,
ksmbd_debug(SMB, "target name is %s\n", target_name); rc = ksmbd_vfs_kern_path_locked(work, link_name, LOOKUP_NO_SYMLINKS, - &path, 0); + &parent_path, &path, 0); if (rc) { if (rc != -ENOENT) goto out; @@ -5613,8 +5617,9 @@ static int smb2_create_link(struct ksmbd_work *work, rc = -EINVAL; out: if (file_present) { - inode_unlock(d_inode(path.dentry->d_parent)); + inode_unlock(d_inode(parent_path.dentry)); path_put(&path); + path_put(&parent_path); } if (!IS_ERR(link_name)) kfree(link_name); diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c index 73ce3fb6e405..1752a6c10bcc 100644 --- a/fs/smb/server/vfs.c +++ b/fs/smb/server/vfs.c @@ -64,13 +64,13 @@ int ksmbd_vfs_lock_parent(struct dentry *parent, struct dentry *child)
static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf, char *pathname, unsigned int flags, + struct path *parent_path, struct path *path) { struct qstr last; struct filename *filename; struct path *root_share_path = &share_conf->vfs_path; int err, type; - struct path parent_path; struct dentry *d;
if (pathname[0] == '\0') { @@ -85,7 +85,7 @@ static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf, return PTR_ERR(filename);
err = vfs_path_parent_lookup(filename, flags, - &parent_path, &last, &type, + parent_path, &last, &type, root_share_path); if (err) { putname(filename); @@ -93,13 +93,13 @@ static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf, }
if (unlikely(type != LAST_NORM)) { - path_put(&parent_path); + path_put(parent_path); putname(filename); return -ENOENT; }
- inode_lock_nested(parent_path.dentry->d_inode, I_MUTEX_PARENT); - d = lookup_one_qstr_excl(&last, parent_path.dentry, 0); + inode_lock_nested(parent_path->dentry->d_inode, I_MUTEX_PARENT); + d = lookup_one_qstr_excl(&last, parent_path->dentry, 0); if (IS_ERR(d)) goto err_out;
@@ -109,15 +109,22 @@ static int ksmbd_vfs_path_lookup_locked(struct ksmbd_share_config *share_conf, }
path->dentry = d; - path->mnt = share_conf->vfs_path.mnt; - path_put(&parent_path); - putname(filename); + path->mnt = mntget(parent_path->mnt); + + if (test_share_config_flag(share_conf, KSMBD_SHARE_FLAG_CROSSMNT)) { + err = follow_down(path); + if (err < 0) { + path_put(path); + goto err_out; + } + }
+ putname(filename); return 0;
err_out: - inode_unlock(parent_path.dentry->d_inode); - path_put(&parent_path); + inode_unlock(d_inode(parent_path->dentry)); + path_put(parent_path); putname(filename); return -ENOENT; } @@ -1196,14 +1203,14 @@ static int ksmbd_vfs_lookup_in_dir(const struct path *dir, char *name, * Return: 0 on success, otherwise error */ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, - unsigned int flags, struct path *path, - bool caseless) + unsigned int flags, struct path *parent_path, + struct path *path, bool caseless) { struct ksmbd_share_config *share_conf = work->tcon->share_conf; int err; - struct path parent_path;
- err = ksmbd_vfs_path_lookup_locked(share_conf, name, flags, path); + err = ksmbd_vfs_path_lookup_locked(share_conf, name, flags, parent_path, + path); if (!err) return 0;
@@ -1218,10 +1225,10 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, path_len = strlen(filepath); remain_len = path_len;
- parent_path = share_conf->vfs_path; - path_get(&parent_path); + *parent_path = share_conf->vfs_path; + path_get(parent_path);
- while (d_can_lookup(parent_path.dentry)) { + while (d_can_lookup(parent_path->dentry)) { char *filename = filepath + path_len - remain_len; char *next = strchrnul(filename, '/'); size_t filename_len = next - filename; @@ -1230,7 +1237,7 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, if (filename_len == 0) break;
- err = ksmbd_vfs_lookup_in_dir(&parent_path, filename, + err = ksmbd_vfs_lookup_in_dir(parent_path, filename, filename_len, work->conn->um); if (err) @@ -1247,8 +1254,8 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, goto out2; else if (is_last) goto out1; - path_put(&parent_path); - parent_path = *path; + path_put(parent_path); + *parent_path = *path;
next[0] = '/'; remain_len -= filename_len + 1; @@ -1256,16 +1263,17 @@ int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name,
err = -EINVAL; out2: - path_put(&parent_path); + path_put(parent_path); out1: kfree(filepath); }
if (!err) { - err = ksmbd_vfs_lock_parent(parent_path.dentry, path->dentry); - if (err) - dput(path->dentry); - path_put(&parent_path); + err = ksmbd_vfs_lock_parent(parent_path->dentry, path->dentry); + if (err) { + path_put(path); + path_put(parent_path); + } } return err; } diff --git a/fs/smb/server/vfs.h b/fs/smb/server/vfs.h index 3e3c92d22e3e..a7cc0aad6d57 100644 --- a/fs/smb/server/vfs.h +++ b/fs/smb/server/vfs.h @@ -115,8 +115,8 @@ int ksmbd_vfs_xattr_stream_name(char *stream_name, char **xattr_stream_name, int ksmbd_vfs_remove_xattr(struct user_namespace *user_ns, const struct path *path, char *attr_name); int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name, - unsigned int flags, struct path *path, - bool caseless); + unsigned int flags, struct path *parent_path, + struct path *path, bool caseless); struct dentry *ksmbd_vfs_kern_path_create(struct ksmbd_work *work, const char *name, unsigned int flags,