| Message ID | 20230607-fs-empty-option-v2-1-ffd0cba3bddb@weissschuh.net (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2] fs: avoid empty option when generating legacy mount string | expand |
On Wed, Jun 07, 2023 at 07:39:09PM +0200, Thomas Weißschuh wrote: > As each option string fragment is always prepended with a comma it would > happen that the whole string always starts with a comma. > This could be interpreted by filesystem drivers as an empty option and > may produce errors. > > For example the NTFS driver from ntfs.ko behaves like this and fails when > mounted via the new API. > > Link: https://github.com/util-linux/util-linux/issues/2298 > Fixes: 3e1aeb00e6d1 ("vfs: Implement a filesystem superblock creation/configuration context") > Cc: stable@vger.kernel.org > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> > --- Applied a fixed up version of v1 to tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git branch: vfs.misc [1/1] fs: avoid empty option when generating legacy mount string https://git.kernel.org/vfs/vfs/c/36851649d3f6 yesterday.
diff --git a/fs/fs_context.c b/fs/fs_context.c index 24ce12f0db32..851214d1d013 100644 --- a/fs/fs_context.c +++ b/fs/fs_context.c @@ -561,7 +561,8 @@ static int legacy_parse_param(struct fs_context *fc, struct fs_parameter *param) return -ENOMEM; } - ctx->legacy_data[size++] = ','; + if (size) + ctx->legacy_data[size++] = ','; len = strlen(param->key); memcpy(ctx->legacy_data + size, param->key, len); size += len;
As each option string fragment is always prepended with a comma it would happen that the whole string always starts with a comma. This could be interpreted by filesystem drivers as an empty option and may produce errors. For example the NTFS driver from ntfs.ko behaves like this and fails when mounted via the new API. Link: https://github.com/util-linux/util-linux/issues/2298 Fixes: 3e1aeb00e6d1 ("vfs: Implement a filesystem superblock creation/configuration context") Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- Changes in v2: - Mention Cc stable@ in sign-off area - Link to v1: https://lore.kernel.org/r/20230607-fs-empty-option-v1-1-20c8dbf4671b@weissschuh.net --- fs/fs_context.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- base-commit: 9561de3a55bed6bdd44a12820ba81ec416e705a7 change-id: 20230607-fs-empty-option-265622371023 Best regards,