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authorPaulo Alcantara <pc@manguebit.com>2023-04-16 15:38:28 -0300
committerSteve French <stfrench@microsoft.com>2023-04-16 18:04:36 -0500
commitd5a863a153e90996ab2aef6b9e08d509f4d5662b (patch)
treef8189068e8f4b663f1196e1e066c828cc968ea62
parent6a8f57ae2eb07ab39a6f0ccad60c760743051026 (diff)
cifs: avoid dup prefix path in dfs_get_automount_devname()
@server->origin_fullpath already contains the tree name + optional prefix, so avoid calling __build_path_from_dentry_optional_prefix() as it might end up duplicating prefix path from @cifs_sb->prepath into final full path. Instead, generate DFS full path by simply merging @server->origin_fullpath with dentry's path. This fixes the following case mount.cifs //root/dfs/dir /mnt/ -o ... ls /mnt/link where cifs_dfs_do_automount() will call smb3_parse_devname() with @devname set to "//root/dfs/dir/link" instead of "//root/dfs/dir/dir/link". Fixes: 7ad54b98fc1f ("cifs: use origin fullpath for automounts") Cc: <stable@vger.kernel.org> # 6.2+ Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/cifs/cifs_dfs_ref.c2
-rw-r--r--fs/cifs/dfs.h22
2 files changed, 18 insertions, 6 deletions
diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index cb40074feb3e..0329a907bdfe 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -171,8 +171,6 @@ static struct vfsmount *cifs_dfs_do_automount(struct path *path)
mnt = ERR_CAST(full_path);
goto out;
}
-
- convert_delimiter(full_path, '/');
cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
tmp = *cur_ctx;
diff --git a/fs/cifs/dfs.h b/fs/cifs/dfs.h
index 13f26e01f7b9..0b8cbf721fff 100644
--- a/fs/cifs/dfs.h
+++ b/fs/cifs/dfs.h
@@ -34,19 +34,33 @@ static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx, const char *p
cifs_remap(cifs_sb), path, ref, tl);
}
+/* Return DFS full path out of a dentry set for automount */
static inline char *dfs_get_automount_devname(struct dentry *dentry, void *page)
{
struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb);
struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
struct TCP_Server_Info *server = tcon->ses->server;
+ size_t len;
+ char *s;
if (unlikely(!server->origin_fullpath))
return ERR_PTR(-EREMOTE);
- return __build_path_from_dentry_optional_prefix(dentry, page,
- server->origin_fullpath,
- strlen(server->origin_fullpath),
- true);
+ s = dentry_path_raw(dentry, page, PATH_MAX);
+ if (IS_ERR(s))
+ return s;
+ /* for root, we want "" */
+ if (!s[1])
+ s++;
+
+ len = strlen(server->origin_fullpath);
+ if (s < (char *)page + len)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ s -= len;
+ memcpy(s, server->origin_fullpath, len);
+ convert_delimiter(s, '/');
+ return s;
}
static inline void dfs_put_root_smb_sessions(struct list_head *head)