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Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 43/43] afs: Use fs_context to pass parameters over automount From: David Howells To: viro@zeniv.linux.org.uk Cc: "Eric W. Biederman" , linux-fsdevel@vger.kernel.org, dhowells@redhat.com, torvalds@linux-foundation.org, ebiederm@xmission.com, linux-security-module@vger.kernel.org Date: Tue, 19 Feb 2019 16:34:26 +0000 Message-ID: <155059406610.12449.7679699218753072978.stgit@warthog.procyon.org.uk> In-Reply-To: <155059366914.12449.4669870128936536848.stgit@warthog.procyon.org.uk> References: <155059366914.12449.4669870128936536848.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Tue, 19 Feb 2019 16:34:28 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Alter the AFS automounting code to create and modify an fs_context struct when parameterising a new mount triggered by an AFS mountpoint rather than constructing device name and option strings. Also remove the cell=, vol= and rwpath options as they are then redundant. The reason they existed is because the 'device name' may be derived literally from a mountpoint object in the filesystem, so default cell and parent-type information needed to be passed in by some other method from the automount routines. The vol= option didn't end up being used. Signed-off-by: David Howells cc: Eric W. Biederman Signed-off-by: Al Viro --- fs/afs/internal.h | 1 fs/afs/mntpt.c | 148 ++++++++++++++++++++++++++++------------------------- fs/afs/super.c | 40 +------------- 3 files changed, 80 insertions(+), 109 deletions(-) diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 3ed0550a2e29..bb1f244b2b3a 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -37,7 +37,6 @@ struct pagevec; struct afs_call; struct afs_fs_context { - bool rwpath; /* T if the parent should be considered R/W */ bool force; /* T to force cell type */ bool autocell; /* T if set auto mount operation */ bool dyn_root; /* T if dynamic root */ diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c index b3f41d27590b..eecd8b699186 100644 --- a/fs/afs/mntpt.c +++ b/fs/afs/mntpt.c @@ -48,6 +48,8 @@ static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out); static unsigned long afs_mntpt_expiry_timeout = 10 * 60; +static const char afs_root_volume[] = "root.cell"; + /* * no valid lookup procedure on this sort of dir */ @@ -69,108 +71,112 @@ static int afs_mntpt_open(struct inode *inode, struct file *file) } /* - * create a vfsmount to be automounted + * Set the parameters for the proposed superblock. */ -static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt) +static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt) { - struct afs_super_info *as; - struct vfsmount *mnt; - struct afs_vnode *vnode; - struct page *page; - char *devname, *options; - bool rwpath = false; + struct afs_fs_context *ctx = fc->fs_private; + struct afs_super_info *src_as = AFS_FS_S(mntpt->d_sb); + struct afs_vnode *vnode = AFS_FS_I(d_inode(mntpt)); + struct afs_cell *cell; + const char *p; int ret; - _enter("{%pd}", mntpt); - - BUG_ON(!d_inode(mntpt)); - - ret = -ENOMEM; - devname = (char *) get_zeroed_page(GFP_KERNEL); - if (!devname) - goto error_no_devname; - - options = (char *) get_zeroed_page(GFP_KERNEL); - if (!options) - goto error_no_options; + if (fc->net_ns != src_as->net_ns) { + put_net(fc->net_ns); + fc->net_ns = get_net(src_as->net_ns); + } - vnode = AFS_FS_I(d_inode(mntpt)); + if (src_as->volume && src_as->volume->type == AFSVL_RWVOL) { + ctx->type = AFSVL_RWVOL; + ctx->force = true; + } + if (ctx->cell) { + afs_put_cell(ctx->net, ctx->cell); + ctx->cell = NULL; + } if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) { /* if the directory is a pseudo directory, use the d_name */ - static const char afs_root_cell[] = ":root.cell."; unsigned size = mntpt->d_name.len; - ret = -ENOENT; - if (size < 2 || size > AFS_MAXCELLNAME) - goto error_no_page; + if (size < 2) + return -ENOENT; + p = mntpt->d_name.name; if (mntpt->d_name.name[0] == '.') { - devname[0] = '%'; - memcpy(devname + 1, mntpt->d_name.name + 1, size - 1); - memcpy(devname + size, afs_root_cell, - sizeof(afs_root_cell)); - rwpath = true; - } else { - devname[0] = '#'; - memcpy(devname + 1, mntpt->d_name.name, size); - memcpy(devname + size + 1, afs_root_cell, - sizeof(afs_root_cell)); + size--; + p++; + ctx->type = AFSVL_RWVOL; + ctx->force = true; } + if (size > AFS_MAXCELLNAME) + return -ENAMETOOLONG; + + cell = afs_lookup_cell(ctx->net, p, size, NULL, false); + if (IS_ERR(cell)) { + pr_err("kAFS: unable to lookup cell '%pd'\n", mntpt); + return PTR_ERR(cell); + } + ctx->cell = cell; + + ctx->volname = afs_root_volume; + ctx->volnamesz = sizeof(afs_root_volume) - 1; } else { /* read the contents of the AFS special symlink */ + struct page *page; loff_t size = i_size_read(d_inode(mntpt)); char *buf; - ret = -EINVAL; + if (src_as->cell) + ctx->cell = afs_get_cell(src_as->cell); + if (size > PAGE_SIZE - 1) - goto error_no_page; + return -EINVAL; page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL); - if (IS_ERR(page)) { - ret = PTR_ERR(page); - goto error_no_page; - } + if (IS_ERR(page)) + return PTR_ERR(page); if (PageError(page)) { ret = afs_bad(AFS_FS_I(d_inode(mntpt)), afs_file_error_mntpt); - goto error; + put_page(page); + return ret; } - buf = kmap_atomic(page); - memcpy(devname, buf, size); - kunmap_atomic(buf); + buf = kmap(page); + ret = vfs_parse_fs_string(fc, "source", buf, size); + kunmap(page); put_page(page); - page = NULL; + if (ret < 0) + return ret; } - /* work out what options we want */ - as = AFS_FS_S(mntpt->d_sb); - if (as->cell) { - memcpy(options, "cell=", 5); - strcpy(options + 5, as->cell->name); - if ((as->volume && as->volume->type == AFSVL_RWVOL) || rwpath) - strcat(options, ",rwpath"); - } + return 0; +} - /* try and do the mount */ - _debug("--- attempting mount %s -o %s ---", devname, options); - mnt = vfs_submount(mntpt, &afs_fs_type, devname, options); - _debug("--- mount result %p ---", mnt); +/* + * create a vfsmount to be automounted + */ +static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt) +{ + struct fs_context *fc; + struct vfsmount *mnt; + int ret; - free_page((unsigned long) devname); - free_page((unsigned long) options); - _leave(" = %p", mnt); - return mnt; + BUG_ON(!d_inode(mntpt)); -error: - put_page(page); -error_no_page: - free_page((unsigned long) options); -error_no_options: - free_page((unsigned long) devname); -error_no_devname: - _leave(" = %d", ret); - return ERR_PTR(ret); + fc = fs_context_for_submount(&afs_fs_type, mntpt); + if (IS_ERR(fc)) + return ERR_CAST(fc); + + ret = afs_mntpt_set_params(fc, mntpt); + if (!ret) + mnt = fc_mount(fc); + else + mnt = ERR_PTR(ret); + + put_fs_context(fc); + return mnt; } /* diff --git a/fs/afs/super.c b/fs/afs/super.c index e1a7a8085262..a07af1ab488d 100644 --- a/fs/afs/super.c +++ b/fs/afs/super.c @@ -66,20 +66,14 @@ static atomic_t afs_count_active_inodes; enum afs_param { Opt_autocell, - Opt_cell, Opt_dyn, - Opt_rwpath, Opt_source, - Opt_vol, }; static const struct fs_parameter_spec afs_param_specs[] = { fsparam_flag ("autocell", Opt_autocell), - fsparam_string("cell", Opt_cell), fsparam_flag ("dyn", Opt_dyn), - fsparam_flag ("rwpath", Opt_rwpath), fsparam_string("source", Opt_source), - fsparam_string("vol", Opt_vol), {} }; @@ -202,8 +196,8 @@ static int afs_show_options(struct seq_file *m, struct dentry *root) * * This can be one of the following: * "%[cell:]volume[.]" R/W volume - * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0), - * or R/W (rwpath=1) volume + * "#[cell:]volume[.]" R/O or R/W volume (R/O parent), + * or R/W (R/W parent) volume * "%[cell:]volume.readonly" R/O volume * "#[cell:]volume.readonly" R/O volume * "%[cell:]volume.backup" Backup volume @@ -234,9 +228,7 @@ static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param) } /* determine the type of volume we're looking for */ - ctx->type = AFSVL_ROVOL; - ctx->force = false; - if (ctx->rwpath || name[0] == '%') { + if (name[0] == '%') { ctx->type = AFSVL_RWVOL; ctx->force = true; } @@ -305,7 +297,6 @@ static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param) { struct fs_parse_result result; struct afs_fs_context *ctx = fc->fs_private; - struct afs_cell *cell; int opt; opt = fs_parse(fc, &afs_fs_parameters, param, &result); @@ -313,21 +304,6 @@ static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param) return opt; switch (opt) { - case Opt_cell: - if (param->size <= 0) - return -EINVAL; - if (param->size > AFS_MAXCELLNAME) - return -ENAMETOOLONG; - - rcu_read_lock(); - cell = afs_lookup_cell_rcu(ctx->net, param->string, param->size); - rcu_read_unlock(); - if (IS_ERR(cell)) - return PTR_ERR(cell); - afs_put_cell(ctx->net, ctx->cell); - ctx->cell = cell; - break; - case Opt_source: return afs_parse_source(fc, param); @@ -339,13 +315,6 @@ static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param) ctx->dyn_root = true; break; - case Opt_rwpath: - ctx->rwpath = true; - break; - - case Opt_vol: - return invalf(fc, "'vol' param is obsolete"); - default: return -EINVAL; } @@ -616,9 +585,6 @@ static int afs_init_fs_context(struct fs_context *fc) struct afs_fs_context *ctx; struct afs_cell *cell; - if (current->nsproxy->net_ns != &init_net) - return -EINVAL; - ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL); if (!ctx) return -ENOMEM;