From 21cb47be6fb9ece7e6ee63f6780986faa384a77c Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:25 +0100 Subject: inode: make init and permission helpers idmapped mount aware The inode_owner_or_capable() helper determines whether the caller is the owner of the inode or is capable with respect to that inode. Allow it to handle idmapped mounts. If the inode is accessed through an idmapped mount it according to 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. Similarly, allow the inode_init_owner() helper to handle idmapped mounts. It initializes a new inode on idmapped mounts by mapping the fsuid and fsgid of the caller from the mount's user namespace. 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/20210121131959.646623-7-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/hugetlbfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/hugetlbfs/inode.c') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index b5c109703daa..6737929e443c 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -836,7 +836,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb, struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode); inode->i_ino = get_next_ino(); - inode_init_owner(inode, dir, mode); + inode_init_owner(&init_user_ns, inode, dir, mode); lockdep_set_class(&inode->i_mapping->i_mmap_rwsem, &hugetlbfs_i_mmap_rwsem_key); inode->i_mapping->a_ops = &hugetlbfs_aops; -- cgit v1.2.3 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/hugetlbfs/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/hugetlbfs/inode.c') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 6737929e443c..327e572b4e00 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -761,7 +761,7 @@ static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) BUG_ON(!inode); - error = setattr_prepare(dentry, attr); + error = setattr_prepare(&init_user_ns, dentry, attr); if (error) return error; @@ -780,7 +780,7 @@ static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) return error; } - setattr_copy(inode, attr); + setattr_copy(&init_user_ns, inode, attr); mark_inode_dirty(inode); return 0; } -- cgit v1.2.3 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/hugetlbfs/inode.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-) (limited to 'fs/hugetlbfs/inode.c') diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 327e572b4e00..c5c32eb59498 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -751,7 +751,8 @@ out: return error; } -static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) +static int hugetlbfs_setattr(struct user_namespace *mnt_userns, + struct dentry *dentry, struct iattr *attr) { struct inode *inode = d_inode(dentry); struct hstate *h = hstate_inode(inode); @@ -898,33 +899,39 @@ static int do_hugetlbfs_mknod(struct inode *dir, return error; } -static int hugetlbfs_mknod(struct inode *dir, - struct dentry *dentry, umode_t mode, dev_t dev) +static int hugetlbfs_mknod(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode, dev_t dev) { return do_hugetlbfs_mknod(dir, dentry, mode, dev, false); } -static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) +static int hugetlbfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir, + struct dentry *dentry, umode_t mode) { - int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); + int retval = hugetlbfs_mknod(&init_user_ns, dir, dentry, + mode | S_IFDIR, 0); if (!retval) inc_nlink(dir); return retval; } -static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) +static int hugetlbfs_create(struct user_namespace *mnt_userns, + struct inode *dir, struct dentry *dentry, + umode_t mode, bool excl) { - return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); + return hugetlbfs_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0); } -static int hugetlbfs_tmpfile(struct inode *dir, - struct dentry *dentry, umode_t mode) +static int hugetlbfs_tmpfile(struct user_namespace *mnt_userns, + struct inode *dir, struct dentry *dentry, + umode_t mode) { return do_hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0, true); } -static int hugetlbfs_symlink(struct inode *dir, - struct dentry *dentry, const char *symname) +static int hugetlbfs_symlink(struct user_namespace *mnt_userns, + struct inode *dir, struct dentry *dentry, + const char *symname) { struct inode *inode; int error = -ENOSPC; -- cgit v1.2.3