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/exfat/file.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/exfat') diff --git a/fs/exfat/file.c b/fs/exfat/file.c index a92478eabfa4..ace35aa8e64b 100644 --- a/fs/exfat/file.c +++ b/fs/exfat/file.c @@ -305,7 +305,7 @@ int exfat_setattr(struct dentry *dentry, struct iattr *attr) ATTR_TIMES_SET); } - error = setattr_prepare(dentry, attr); + error = setattr_prepare(&init_user_ns, dentry, attr); attr->ia_valid = ia_valid; if (error) goto out; @@ -340,7 +340,7 @@ int exfat_setattr(struct dentry *dentry, struct iattr *attr) up_write(&EXFAT_I(inode)->truncate_lock); } - setattr_copy(inode, attr); + setattr_copy(&init_user_ns, inode, attr); exfat_truncate_atime(&inode->i_atime); mark_inode_dirty(inode); -- cgit v1.2.1 From 0d56a4518d5eaf595a24ab2202e171330bb2ed72 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:30 +0100 Subject: stat: handle idmapped mounts The generic_fillattr() helper fills in the basic attributes associated with an inode. Enable it to handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace before we store the uid and gid. 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/20210121131959.646623-12-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Reviewed-by: James Morris Signed-off-by: Christian Brauner --- fs/exfat/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/exfat') diff --git a/fs/exfat/file.c b/fs/exfat/file.c index ace35aa8e64b..e9705b3295d3 100644 --- a/fs/exfat/file.c +++ b/fs/exfat/file.c @@ -273,7 +273,7 @@ int exfat_getattr(const struct path *path, struct kstat *stat, struct inode *inode = d_backing_inode(path->dentry); struct exfat_inode_info *ei = EXFAT_I(inode); - generic_fillattr(inode, stat); + generic_fillattr(&init_user_ns, inode, stat); exfat_truncate_atime(&stat->atime); stat->result_mask |= STATX_BTIME; stat->btime.tv_sec = ei->i_crtime.tv_sec; -- 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/exfat/exfat_fs.h | 8 +++++--- fs/exfat/file.c | 8 +++++--- fs/exfat/namei.c | 14 ++++++++------ 3 files changed, 18 insertions(+), 12 deletions(-) (limited to 'fs/exfat') diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index b8f0e829ecbd..d905bb9cd2ca 100644 --- a/fs/exfat/exfat_fs.h +++ b/fs/exfat/exfat_fs.h @@ -416,9 +416,11 @@ int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count); extern const struct file_operations exfat_file_operations; int __exfat_truncate(struct inode *inode, loff_t new_size); void exfat_truncate(struct inode *inode, loff_t size); -int exfat_setattr(struct dentry *dentry, struct iattr *attr); -int exfat_getattr(const struct path *path, struct kstat *stat, - unsigned int request_mask, unsigned int query_flags); +int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct iattr *attr); +int exfat_getattr(struct user_namespace *mnt_userns, const struct path *path, + struct kstat *stat, unsigned int request_mask, + unsigned int query_flags); int exfat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync); /* namei.c */ diff --git a/fs/exfat/file.c b/fs/exfat/file.c index e9705b3295d3..3aa6eb4de5e3 100644 --- a/fs/exfat/file.c +++ b/fs/exfat/file.c @@ -267,8 +267,9 @@ write_size: mutex_unlock(&sbi->s_lock); } -int exfat_getattr(const struct path *path, struct kstat *stat, - unsigned int request_mask, unsigned int query_flags) +int exfat_getattr(struct user_namespace *mnt_uerns, const struct path *path, + struct kstat *stat, unsigned int request_mask, + unsigned int query_flags) { struct inode *inode = d_backing_inode(path->dentry); struct exfat_inode_info *ei = EXFAT_I(inode); @@ -282,7 +283,8 @@ int exfat_getattr(const struct path *path, struct kstat *stat, return 0; } -int exfat_setattr(struct dentry *dentry, struct iattr *attr) +int exfat_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct iattr *attr) { struct exfat_sb_info *sbi = EXFAT_SB(dentry->d_sb); struct inode *inode = dentry->d_inode; diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c index 2932b23a3b6c..d9e8ec689c55 100644 --- a/fs/exfat/namei.c +++ b/fs/exfat/namei.c @@ -541,8 +541,8 @@ out: return ret; } -static int exfat_create(struct inode *dir, struct dentry *dentry, umode_t mode, - bool excl) +static int exfat_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; @@ -827,7 +827,8 @@ unlock: return err; } -static int exfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) +static int exfat_mkdir(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode) { struct super_block *sb = dir->i_sb; struct inode *inode; @@ -1318,9 +1319,10 @@ out: return ret; } -static int exfat_rename(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry, - unsigned int flags) +static int exfat_rename(struct user_namespace *mnt_userns, + struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry, + unsigned int flags) { struct inode *old_inode, *new_inode; struct super_block *sb = old_dir->i_sb; -- cgit v1.2.1