From 2f221d6f7b881d95de1f356a3097d755ab1e47d4 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:26 +0100 Subject: attr: handle idmapped mounts When file attributes are changed most filesystems rely on the setattr_prepare(), setattr_copy(), and notify_change() helpers for initialization and permission checking. Let them handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Helpers that perform checks on the ia_uid and ia_gid fields in struct iattr assume that ia_uid and ia_gid are intended values and have already been mapped correctly at the userspace-kernelspace boundary as we already do today. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/affs/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/affs') diff --git a/fs/affs/inode.c b/fs/affs/inode.c index 044412110b52..767e5bdfb703 100644 --- a/fs/affs/inode.c +++ b/fs/affs/inode.c @@ -223,7 +223,7 @@ affs_notify_change(struct dentry *dentry, struct iattr *attr) pr_debug("notify_change(%lu,0x%x)\n", inode->i_ino, attr->ia_valid); - error = setattr_prepare(dentry, attr); + error = setattr_prepare(&init_user_ns, dentry, attr); if (error) goto out; @@ -249,7 +249,7 @@ affs_notify_change(struct dentry *dentry, struct iattr *attr) affs_truncate(inode); } - setattr_copy(inode, attr); + setattr_copy(&init_user_ns, inode, attr); mark_inode_dirty(inode); if (attr->ia_valid & ATTR_MODE) -- cgit v1.2.1 From 549c7297717c32ee53f156cd949e055e601f67bb Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:43 +0100 Subject: fs: make helpers idmap mount aware Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/affs/affs.h | 24 +++++++++++++++--------- fs/affs/inode.c | 3 ++- fs/affs/namei.c | 15 +++++++++------ 3 files changed, 26 insertions(+), 16 deletions(-) (limited to 'fs/affs') diff --git a/fs/affs/affs.h b/fs/affs/affs.h index a755bef7c4c7..bfa89e131ead 100644 --- a/fs/affs/affs.h +++ b/fs/affs/affs.h @@ -167,27 +167,33 @@ extern const struct export_operations affs_export_ops; extern int affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len); extern struct dentry *affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int); extern int affs_unlink(struct inode *dir, struct dentry *dentry); -extern int affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool); -extern int affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode); +extern int affs_create(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode, bool); +extern int affs_mkdir(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode); extern int affs_rmdir(struct inode *dir, struct dentry *dentry); extern int affs_link(struct dentry *olddentry, struct inode *dir, struct dentry *dentry); -extern int affs_symlink(struct inode *dir, struct dentry *dentry, - const char *symname); -extern int affs_rename2(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry, - unsigned int flags); +extern int affs_symlink(struct user_namespace *mnt_userns, + struct inode *dir, struct dentry *dentry, + const char *symname); +extern int affs_rename2(struct user_namespace *mnt_userns, + struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry, + unsigned int flags); /* inode.c */ extern struct inode *affs_new_inode(struct inode *dir); -extern int affs_notify_change(struct dentry *dentry, struct iattr *attr); +extern int affs_notify_change(struct user_namespace *mnt_userns, + struct dentry *dentry, struct iattr *attr); extern void affs_evict_inode(struct inode *inode); extern struct inode *affs_iget(struct super_block *sb, unsigned long ino); extern int affs_write_inode(struct inode *inode, struct writeback_control *wbc); -extern int affs_add_entry(struct inode *dir, struct inode *inode, struct dentry *dentry, s32 type); +extern int affs_add_entry(struct inode *dir, struct inode *inode, + struct dentry *dentry, s32 type); /* file.c */ diff --git a/fs/affs/inode.c b/fs/affs/inode.c index 767e5bdfb703..2352a75bd9d6 100644 --- a/fs/affs/inode.c +++ b/fs/affs/inode.c @@ -216,7 +216,8 @@ affs_write_inode(struct inode *inode, struct writeback_control *wbc) } int -affs_notify_change(struct dentry *dentry, struct iattr *attr) +affs_notify_change(struct user_namespace *mnt_userns, struct dentry *dentry, + struct iattr *attr) { struct inode *inode = d_inode(dentry); int error; diff --git a/fs/affs/namei.c b/fs/affs/namei.c index 41c5749f4db7..9ad22befce28 100644 --- a/fs/affs/namei.c +++ b/fs/affs/namei.c @@ -242,7 +242,8 @@ affs_unlink(struct inode *dir, struct dentry *dentry) } int -affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) +affs_create(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode, bool excl) { struct super_block *sb = dir->i_sb; struct inode *inode; @@ -273,7 +274,8 @@ affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) } int -affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) +affs_mkdir(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode) { struct inode *inode; int error; @@ -311,7 +313,8 @@ affs_rmdir(struct inode *dir, struct dentry *dentry) } int -affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) +affs_symlink(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, const char *symname) { struct super_block *sb = dir->i_sb; struct buffer_head *bh; @@ -498,9 +501,9 @@ done: return retval; } -int affs_rename2(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry, - unsigned int flags) +int affs_rename2(struct user_namespace *mnt_userns, struct inode *old_dir, + struct dentry *old_dentry, struct inode *new_dir, + struct dentry *new_dentry, unsigned int flags) { if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) -- cgit v1.2.1