>From 94195ce5b06915846d14eaa35d9274c0315b46a0 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 4 Oct 2012 13:34:45 -0700 Subject: [PATCH 1/4] userns: Allow for fuse filesystems outside the initial user namespace Signed-off-by: "Eric W. Biederman" --- fs/fuse/dev.c | 10 +++++----- fs/fuse/dir.c | 41 ++++++++++++++++++++++++++++++----------- fs/fuse/fuse_i.h | 3 +++ fs/fuse/inode.c | 10 ++++++++-- 4 files changed, 46 insertions(+), 18 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index ca887314aba9..e01f30c51b3c 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -124,10 +124,10 @@ static void __fuse_put_request(struct fuse_req *req) atomic_dec(&req->count); } -static void fuse_req_init_context(struct fuse_req *req) +static void fuse_req_init_context(struct fuse_conn *fc, struct fuse_req *req) { - req->in.h.uid = from_kuid_munged(&init_user_ns, current_fsuid()); - req->in.h.gid = from_kgid_munged(&init_user_ns, current_fsgid()); + req->in.h.uid = from_kuid_munged(fc->user_ns, current_fsuid()); + req->in.h.gid = from_kgid_munged(fc->user_ns, current_fsgid()); req->in.h.pid = current->pid; } @@ -168,7 +168,7 @@ static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages, goto out; } - fuse_req_init_context(req); + fuse_req_init_context(fc, req); req->waiting = 1; req->background = for_background; return req; @@ -257,7 +257,7 @@ struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc, if (!req) req = get_reserved_req(fc, file); - fuse_req_init_context(req); + fuse_req_init_context(fc, req); req->waiting = 1; req->background = 0; return req; diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index de1d84af9f7c..d74c75a057cd 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -886,7 +886,7 @@ static int fuse_link(struct dentry *entry, struct inode *newdir, return err; } -static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr, +static int fuse_fillattr(struct inode *inode, struct fuse_attr *attr, struct kstat *stat) { unsigned int blkbits; @@ -905,8 +905,12 @@ static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr, stat->ino = attr->ino; stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777); stat->nlink = attr->nlink; - stat->uid = make_kuid(&init_user_ns, attr->uid); - stat->gid = make_kgid(&init_user_ns, attr->gid); + stat->uid = make_kuid(fc->user_ns, attr->uid); + if (!uid_valid(stat->uid)) + return -EOVERFLOW; + stat->gid = make_kgid(fc->user_ns, attr->gid); + if (!gid_valid(stat->gid)) + return -EOVERFLOW; stat->rdev = inode->i_rdev; stat->atime.tv_sec = attr->atime; stat->atime.tv_nsec = attr->atimensec; @@ -923,6 +927,7 @@ static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr, blkbits = inode->i_sb->s_blocksize_bits; stat->blksize = 1 << blkbits; + return 0; } static int fuse_do_getattr(struct inode *inode, struct kstat *stat, @@ -973,7 +978,8 @@ static int fuse_do_getattr(struct inode *inode, struct kstat *stat, attr_timeout(&outarg), attr_version); if (stat) - fuse_fillattr(inode, &outarg.attr, stat); + err = fuse_fillattr(inode, &outarg.attr, + stat); } } return err; @@ -1556,17 +1562,25 @@ static bool update_mtime(unsigned ivalid, bool trust_local_mtime) return true; } -static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg, - bool trust_local_cmtime) +static int iattr_to_fattr(struct fuse_conn *fc, struct iattr *iattr, + struct fuse_setattr_in *arg, bool trust_local_cmtime) { unsigned ivalid = iattr->ia_valid; if (ivalid & ATTR_MODE) arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode; - if (ivalid & ATTR_UID) - arg->valid |= FATTR_UID, arg->uid = from_kuid(&init_user_ns, iattr->ia_uid); - if (ivalid & ATTR_GID) - arg->valid |= FATTR_GID, arg->gid = from_kgid(&init_user_ns, iattr->ia_gid); + if (ivalid & ATTR_UID) { + arg->valid |= FATTR_UID; + arg->uid = from_kuid(fc->user_ns, iattr->ia_uid); + if (arg->uid == (uid_t)-1) + return -EOVERFLOW; + } + if (ivalid & ATTR_GID) { + arg->valid |= FATTR_GID; + arg->gid = from_kgid(fc->user_ns, iattr->ia_gid); + if (arg->gid == (gid_t)-1) + return -EOVERFLOW; + } if (ivalid & ATTR_SIZE) arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size; if (ivalid & ATTR_ATIME) { @@ -1588,6 +1602,7 @@ static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg, arg->ctime = iattr->ia_ctime.tv_sec; arg->ctimensec = iattr->ia_ctime.tv_nsec; } + return 0; } /* @@ -1741,7 +1756,11 @@ int fuse_do_setattr(struct inode *inode, struct iattr *attr, memset(&inarg, 0, sizeof(inarg)); memset(&outarg, 0, sizeof(outarg)); - iattr_to_fattr(attr, &inarg, trust_local_cmtime); + err = iattr_to_fattr(fc, attr, &inarg, trust_local_cmtime); + if (err) { + goto error; + } + if (file) { struct fuse_file *ff = file->private_data; inarg.valid |= FATTR_FH; diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index e8e47a6ab518..e7dbbb5d62b4 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -598,6 +598,9 @@ struct fuse_conn { /** Read/write semaphore to hold when accessing sb. */ struct rw_semaphore killsb; + + /** User namespace to communicate uids and gids to the fuse daemon */ + struct user_namespace *user_ns; }; static inline struct fuse_conn *get_fuse_conn_super(struct super_block *sb) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 03246cd9d47a..894288f7ad67 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -20,6 +20,7 @@ #include #include #include +#include MODULE_AUTHOR("Miklos Szeredi "); MODULE_DESCRIPTION("Filesystem in Userspace"); @@ -577,8 +578,8 @@ static int fuse_show_options(struct seq_file *m, struct dentry *root) struct super_block *sb = root->d_sb; struct fuse_conn *fc = get_fuse_conn_super(sb); - seq_printf(m, ",user_id=%u", from_kuid_munged(&init_user_ns, fc->user_id)); - seq_printf(m, ",group_id=%u", from_kgid_munged(&init_user_ns, fc->group_id)); + seq_printf(m, ",user_id=%u", from_kuid_munged(fc->user_ns, fc->user_id)); + seq_printf(m, ",group_id=%u", from_kgid_munged(fc->user_ns, fc->group_id)); if (fc->flags & FUSE_DEFAULT_PERMISSIONS) seq_puts(m, ",default_permissions"); if (fc->flags & FUSE_ALLOW_OTHER) @@ -616,6 +617,7 @@ void fuse_conn_init(struct fuse_conn *fc) fc->initialized = 0; fc->attr_version = 1; get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key)); + fc->user_ns = get_user_ns(current_user_ns()); } EXPORT_SYMBOL_GPL(fuse_conn_init); @@ -624,6 +626,8 @@ void fuse_conn_put(struct fuse_conn *fc) if (atomic_dec_and_test(&fc->count)) { if (fc->destroy_req) fuse_request_free(fc->destroy_req); + put_user_ns(fc->user_ns); + fc->user_ns = NULL; fc->release(fc); } } @@ -1033,6 +1037,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_time_gran = 1; sb->s_export_op = &fuse_export_operations; + sb->s_user_ns = get_user_ns(current_user_ns()); file = fget(d.fd); err = -EINVAL; @@ -1149,6 +1154,7 @@ static void fuse_kill_sb_anon(struct super_block *sb) } kill_anon_super(sb); + put_user_ns(sb->s_user_ns); } static struct file_system_type fuse_fs_type = { -- 1.9.1