From d1aabc2132d29224caa3c994dadd8224dc473ed9 Mon Sep 17 00:00:00 2001 From: Zhan Xusheng Date: Fri, 8 May 2026 15:29:34 +0800 Subject: [PATCH] ntfs: fix missing kstrdup() error check in ntfs_write_volume_label() ntfs_write_volume_label() does not check the return value of kstrdup(). If the allocation fails, vol->volume_label is set to NULL while the function returns success. A subsequent FS_IOC_GETFSLABEL then returns an empty string even though the on-disk label was updated correctly. Fix by allocating the new label before taking vol_ni->mrec_lock and updating any on-disk metadata, so an -ENOMEM from kstrdup() leaves both the in-memory and on-disk labels untouched and consistent. On success the preallocated copy replaces the old vol->volume_label. Also move mark_inode_dirty_sync() into the success path so that it is not called when no metadata was actually modified. Fixes: 6251f0b0de7d ("ntfs: update super block operations") Suggested-by: Hyunchul Lee Signed-off-by: Zhan Xusheng Reviewed-by: Hyunchul Lee Signed-off-by: Namjae Jeon --- fs/ntfs/super.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c index e9de84fb8297..d282cf6e712e 100644 --- a/fs/ntfs/super.c +++ b/fs/ntfs/super.c @@ -413,6 +413,7 @@ int ntfs_write_volume_label(struct ntfs_volume *vol, char *label) { struct ntfs_inode *vol_ni = NTFS_I(vol->vol_ino); struct ntfs_attr_search_ctx *ctx; + char *new_label; __le16 *uname; int uname_len, ret; @@ -425,7 +426,7 @@ int ntfs_write_volume_label(struct ntfs_volume *vol, char *label) return uname_len; } - if (uname_len > NTFS_MAX_LABEL_LEN) { + if (uname_len > NTFS_MAX_LABEL_LEN) { ntfs_error(vol->sb, "Volume label is too long (max %d characters).", NTFS_MAX_LABEL_LEN); @@ -433,11 +434,22 @@ int ntfs_write_volume_label(struct ntfs_volume *vol, char *label) return -EINVAL; } + /* + * Allocate the in-memory label copy up front. If kstrdup() fails we + * bail out before touching on-disk metadata, so the in-memory label + * and the on-disk label stay in sync. + */ + new_label = kstrdup(label, GFP_KERNEL); + if (!new_label) { + kvfree(uname); + return -ENOMEM; + } + mutex_lock(&vol_ni->mrec_lock); ctx = ntfs_attr_get_search_ctx(vol_ni, NULL); if (!ctx) { ret = -ENOMEM; - goto out; + goto out; } if (!ntfs_attr_lookup(AT_VOLUME_NAME, NULL, 0, 0, 0, NULL, 0, @@ -450,12 +462,14 @@ int ntfs_write_volume_label(struct ntfs_volume *vol, char *label) out: mutex_unlock(&vol_ni->mrec_lock); kvfree(uname); - mark_inode_dirty_sync(vol->vol_ino); if (ret >= 0) { kfree(vol->volume_label); - vol->volume_label = kstrdup(label, GFP_KERNEL); + vol->volume_label = new_label; + mark_inode_dirty_sync(vol->vol_ino); ret = 0; + } else { + kfree(new_label); } return ret; }