diff options
| -rw-r--r-- | tools/virtiofsd/passthrough_ll.c | 229 |
1 files changed, 200 insertions, 29 deletions
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index e694980a53..e1c45bb420 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -234,6 +234,11 @@ static struct lo_inode *lo_find(struct lo_data *lo, struct stat *st, static int xattr_map_client(const struct lo_data *lo, const char *client_name, char **out_name); +#define FCHDIR_NOFAIL(fd) do { \ + int fchdir_res = fchdir(fd); \ + assert(fchdir_res == 0); \ + } while (0) + static bool is_dot_or_dotdot(const char *name) { return name[0] == '.' && @@ -288,7 +293,6 @@ static bool is_fscreate_usable(struct lo_data *lo) } /* Helpers to set/reset fscreate */ -__attribute__((unused)) static int open_set_proc_fscreate(struct lo_data *lo, const void *ctx, size_t ctxlen, int *fd) { @@ -316,7 +320,6 @@ out: return err; } -__attribute__((unused)) static void close_reset_proc_fscreate(int fd) { if ((write(fd, NULL, 0)) == -1) { @@ -1354,16 +1357,103 @@ static void lo_restore_cred_gain_cap(struct lo_cred *old, bool restore_umask, } } +static int do_mknod_symlink_secctx(fuse_req_t req, struct lo_inode *dir, + const char *name, const char *secctx_name) +{ + int path_fd, err; + char procname[64]; + struct lo_data *lo = lo_data(req); + + if (!req->secctx.ctxlen) { + return 0; + } + + /* Open newly created element with O_PATH */ + path_fd = openat(dir->fd, name, O_PATH | O_NOFOLLOW); + err = path_fd == -1 ? errno : 0; + if (err) { + return err; + } + sprintf(procname, "%i", path_fd); + FCHDIR_NOFAIL(lo->proc_self_fd); + /* Set security context. This is not atomic w.r.t file creation */ + err = setxattr(procname, secctx_name, req->secctx.ctx, req->secctx.ctxlen, + 0); + if (err) { + err = errno; + } + FCHDIR_NOFAIL(lo->root.fd); + close(path_fd); + return err; +} + +static int do_mknod_symlink(fuse_req_t req, struct lo_inode *dir, + const char *name, mode_t mode, dev_t rdev, + const char *link) +{ + int err, fscreate_fd = -1; + const char *secctx_name = req->secctx.name; + struct lo_cred old = {}; + struct lo_data *lo = lo_data(req); + char *mapped_name = NULL; + bool secctx_enabled = req->secctx.ctxlen; + bool do_fscreate = false; + + if (secctx_enabled && lo->xattrmap) { + err = xattr_map_client(lo, req->secctx.name, &mapped_name); + if (err < 0) { + return -err; + } + secctx_name = mapped_name; + } + + /* + * If security xattr has not been remapped and selinux is enabled on + * host, set fscreate and no need to do a setxattr() after file creation + */ + if (secctx_enabled && !mapped_name && lo->use_fscreate) { + do_fscreate = true; + err = open_set_proc_fscreate(lo, req->secctx.ctx, req->secctx.ctxlen, + &fscreate_fd); + if (err) { + goto out; + } + } + + err = lo_change_cred(req, &old, lo->change_umask && !S_ISLNK(mode)); + if (err) { + goto out; + } + + err = mknod_wrapper(dir->fd, name, link, mode, rdev); + err = err == -1 ? errno : 0; + lo_restore_cred(&old, lo->change_umask && !S_ISLNK(mode)); + if (err) { + goto out; + } + + if (!do_fscreate) { + err = do_mknod_symlink_secctx(req, dir, name, secctx_name); + if (err) { + unlinkat(dir->fd, name, S_ISDIR(mode) ? AT_REMOVEDIR : 0); + } + } +out: + if (fscreate_fd != -1) { + close_reset_proc_fscreate(fscreate_fd); + } + g_free(mapped_name); + return err; +} + static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent, const char *name, mode_t mode, dev_t rdev, const char *link) { - int res; int saverr; struct lo_data *lo = lo_data(req); struct lo_inode *dir; struct fuse_entry_param e; - struct lo_cred old = {}; if (is_empty(name)) { fuse_reply_err(req, ENOENT); @@ -1381,21 +1471,11 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent, return; } - saverr = lo_change_cred(req, &old, lo->change_umask && !S_ISLNK(mode)); + saverr = do_mknod_symlink(req, dir, name, mode, rdev, link); if (saverr) { goto out; } - res = mknod_wrapper(dir->fd, name, link, mode, rdev); - - saverr = errno; - - lo_restore_cred(&old, lo->change_umask && !S_ISLNK(mode)); - - if (res == -1) { - goto out; - } - saverr = lo_do_lookup(req, parent, name, &e, NULL); if (saverr) { goto out; @@ -2071,13 +2151,16 @@ static int lo_do_open(struct lo_data *lo, struct lo_inode *inode, return 0; } -static int do_lo_create(fuse_req_t req, struct lo_inode *parent_inode, - const char *name, mode_t mode, - struct fuse_file_info *fi, int* open_fd) +static int do_create_nosecctx(fuse_req_t req, struct lo_inode *parent_inode, + const char *name, mode_t mode, + struct fuse_file_info *fi, int *open_fd) { - int err = 0, fd; + int err, fd; struct lo_cred old = {}; struct lo_data *lo = lo_data(req); + int flags; + + flags = fi->flags | O_CREAT | O_EXCL; err = lo_change_cred(req, &old, lo->change_umask); if (err) { @@ -2085,13 +2168,106 @@ static int do_lo_create(fuse_req_t req, struct lo_inode *parent_inode, } /* Try to create a new file but don't open existing files */ - fd = openat(parent_inode->fd, name, fi->flags | O_CREAT | O_EXCL, mode); - if (fd == -1) { - err = errno; - } else { + fd = openat(parent_inode->fd, name, flags, mode); + err = fd == -1 ? errno : 0; + lo_restore_cred(&old, lo->change_umask); + if (!err) { *open_fd = fd; } - lo_restore_cred(&old, lo->change_umask); + return err; +} + +static int do_create_secctx_fscreate(fuse_req_t req, + struct lo_inode *parent_inode, + const char *name, mode_t mode, + struct fuse_file_info *fi, int *open_fd) +{ + int err = 0, fd = -1, fscreate_fd = -1; + struct lo_data *lo = lo_data(req); + + err = open_set_proc_fscreate(lo, req->secctx.ctx, req->secctx.ctxlen, + &fscreate_fd); + if (err) { + return err; + } + + err = do_create_nosecctx(req, parent_inode, name, mode, fi, &fd); + + close_reset_proc_fscreate(fscreate_fd); + if (!err) { + *open_fd = fd; + } + return err; +} + +static int do_create_secctx_noatomic(fuse_req_t req, + struct lo_inode *parent_inode, + const char *name, mode_t mode, + struct fuse_file_info *fi, + const char *secctx_name, int *open_fd) +{ + int err = 0, fd = -1; + + err = do_create_nosecctx(req, parent_inode, name, mode, fi, &fd); + if (err) { + goto out; + } + + /* Set security context. This is not atomic w.r.t file creation */ + err = fsetxattr(fd, secctx_name, req->secctx.ctx, req->secctx.ctxlen, 0); + err = err == -1 ? errno : 0; +out: + if (!err) { + *open_fd = fd; + } else { + if (fd != -1) { + close(fd); + unlinkat(parent_inode->fd, name, 0); + } + } + return err; +} + +static int do_lo_create(fuse_req_t req, struct lo_inode *parent_inode, + const char *name, mode_t mode, + struct fuse_file_info *fi, int *open_fd) +{ + struct lo_data *lo = lo_data(req); + char *mapped_name = NULL; + int err; + const char *ctxname = req->secctx.name; + bool secctx_enabled = req->secctx.ctxlen; + + if (secctx_enabled && lo->xattrmap) { + err = xattr_map_client(lo, req->secctx.name, &mapped_name); + if (err < 0) { + return -err; + } + + ctxname = mapped_name; + } + + if (secctx_enabled) { + /* + * If security.selinux has not been remapped and selinux is enabled, + * use fscreate to set context before file creation. + * Otherwise fallback to non-atomic method of file creation + * and xattr settting. + */ + if (!mapped_name && lo->use_fscreate) { + err = do_create_secctx_fscreate(req, parent_inode, name, mode, fi, + open_fd); + goto out; + } + + err = do_create_secctx_noatomic(req, parent_inode, name, mode, fi, + ctxname, open_fd); + } else { + err = do_create_nosecctx(req, parent_inode, name, mode, fi, open_fd); + } + +out: + g_free(mapped_name); return err; } @@ -2935,11 +3111,6 @@ static int xattr_map_server(const struct lo_data *lo, const char *server_name, return -ENODATA; } -#define FCHDIR_NOFAIL(fd) do { \ - int fchdir_res = fchdir(fd); \ - assert(fchdir_res == 0); \ - } while (0) - static bool block_xattr(struct lo_data *lo, const char *name) { /* |