diff options
| -rw-r--r-- | docs/tools/virtiofsd.rst | 3 | ||||
| -rw-r--r-- | tools/virtiofsd/helper.c | 1 | ||||
| -rw-r--r-- | tools/virtiofsd/passthrough_ll.c | 115 |
3 files changed, 118 insertions, 1 deletions
diff --git a/docs/tools/virtiofsd.rst b/docs/tools/virtiofsd.rst index a6c3502710..c4ac7fdf38 100644 --- a/docs/tools/virtiofsd.rst +++ b/docs/tools/virtiofsd.rst @@ -101,6 +101,9 @@ Options Enable/disable extended attributes (xattr) on files and directories. The default is ``no_xattr``. + * posix_acl|no_posix_acl - + Enable/disable posix acl support. Posix ACLs are disabled by default`. + .. option:: --socket-path=PATH Listen on vhost-user UNIX domain socket at PATH. diff --git a/tools/virtiofsd/helper.c b/tools/virtiofsd/helper.c index 5e98ed702b..a8295d975a 100644 --- a/tools/virtiofsd/helper.c +++ b/tools/virtiofsd/helper.c @@ -186,6 +186,7 @@ void fuse_cmdline_help(void) " to virtiofsd from guest applications.\n" " default: no_allow_direct_io\n" " -o announce_submounts Announce sub-mount points to the guest\n" + " -o posix_acl/no_posix_acl Enable/Disable posix_acl. (default: disabled)\n" ); } diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 6e30fd9113..38b2af8599 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -175,7 +175,7 @@ struct lo_data { int user_killpriv_v2, killpriv_v2; /* If set, virtiofsd is responsible for setting umask during creation */ bool change_umask; - int posix_acl; + int user_posix_acl, posix_acl; }; static const struct fuse_opt lo_opts[] = { @@ -208,6 +208,8 @@ static const struct fuse_opt lo_opts[] = { { "announce_submounts", offsetof(struct lo_data, announce_submounts), 1 }, { "killpriv_v2", offsetof(struct lo_data, user_killpriv_v2), 1 }, { "no_killpriv_v2", offsetof(struct lo_data, user_killpriv_v2), 0 }, + { "posix_acl", offsetof(struct lo_data, user_posix_acl), 1 }, + { "no_posix_acl", offsetof(struct lo_data, user_posix_acl), 0 }, FUSE_OPT_END }; static bool use_syslog = false; @@ -706,6 +708,32 @@ static void lo_init(void *userdata, struct fuse_conn_info *conn) conn->want &= ~FUSE_CAP_HANDLE_KILLPRIV_V2; lo->killpriv_v2 = 0; } + + if (lo->user_posix_acl == 1) { + /* + * User explicitly asked for this option. Enable it unconditionally. + * If connection does not have this capability, print error message + * now. It will fail later in fuse_lowlevel.c + */ + if (!(conn->capable & FUSE_CAP_POSIX_ACL) || + !(conn->capable & FUSE_CAP_DONT_MASK) || + !(conn->capable & FUSE_CAP_SETXATTR_EXT)) { + fuse_log(FUSE_LOG_ERR, "lo_init: Can not enable posix acl." + " kernel does not support FUSE_POSIX_ACL, FUSE_DONT_MASK" + " or FUSE_SETXATTR_EXT capability.\n"); + } else { + fuse_log(FUSE_LOG_DEBUG, "lo_init: enabling posix acl\n"); + } + + conn->want |= FUSE_CAP_POSIX_ACL | FUSE_CAP_DONT_MASK | + FUSE_CAP_SETXATTR_EXT; + lo->change_umask = true; + lo->posix_acl = true; + } else { + /* User either did not specify anything or wants it disabled */ + fuse_log(FUSE_LOG_DEBUG, "lo_init: disabling posix_acl\n"); + conn->want &= ~FUSE_CAP_POSIX_ACL; + } } static void lo_getattr(fuse_req_t req, fuse_ino_t ino, @@ -2783,6 +2811,63 @@ static int xattr_map_server(const struct lo_data *lo, const char *server_name, assert(fchdir_res == 0); \ } while (0) +static bool block_xattr(struct lo_data *lo, const char *name) +{ + /* + * If user explicitly enabled posix_acl or did not provide any option, + * do not block acl. Otherwise block system.posix_acl_access and + * system.posix_acl_default xattrs. + */ + if (lo->user_posix_acl) { + return false; + } + if (!strcmp(name, "system.posix_acl_access") || + !strcmp(name, "system.posix_acl_default")) + return true; + + return false; +} + +/* + * Returns number of bytes in xattr_list after filtering on success. This + * could be zero as well if nothing is left after filtering. + * + * Returns negative error code on failure. + * xattr_list is modified in place. + */ +static int remove_blocked_xattrs(struct lo_data *lo, char *xattr_list, + unsigned in_size) +{ + size_t out_index, in_index; + + /* + * As of now we only filter out acl xattrs. If acls are enabled or + * they have not been explicitly disabled, there is nothing to + * filter. + */ + if (lo->user_posix_acl) { + return in_size; + } + + out_index = 0; + in_index = 0; + while (in_index < in_size) { + char *in_ptr = xattr_list + in_index; + + /* Length of current attribute name */ + size_t in_len = strlen(xattr_list + in_index) + 1; + + if (!block_xattr(lo, in_ptr)) { + if (in_index != out_index) { + memmove(xattr_list + out_index, xattr_list + in_index, in_len); + } + out_index += in_len; + } + in_index += in_len; + } + return out_index; +} + static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, size_t size) { @@ -2796,6 +2881,11 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, int saverr; int fd = -1; + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name = NULL; name = in_name; if (lo->xattrmap) { @@ -2986,6 +3076,12 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) goto out; } } + + ret = remove_blocked_xattrs(lo, value, ret); + if (ret <= 0) { + saverr = -ret; + goto out; + } fuse_reply_buf(req, value, ret); } else { /* @@ -3026,6 +3122,11 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *in_name, bool cap_fsetid_dropped = false; struct lo_cred old = {}; + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name = NULL; name = in_name; if (lo->xattrmap) { @@ -3118,6 +3219,11 @@ static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *in_name) int saverr; int fd = -1; + if (block_xattr(lo, in_name)) { + fuse_reply_err(req, EOPNOTSUPP); + return; + } + mapped_name = NULL; name = in_name; if (lo->xattrmap) { @@ -3795,6 +3901,7 @@ int main(int argc, char *argv[]) .allow_direct_io = 0, .proc_self_fd = -1, .user_killpriv_v2 = -1, + .user_posix_acl = -1, }; struct lo_map_elem *root_elem; struct lo_map_elem *reserve_elem; @@ -3923,6 +4030,12 @@ int main(int argc, char *argv[]) exit(1); } + if (lo.user_posix_acl == 1 && !lo.xattr) { + fuse_log(FUSE_LOG_ERR, "Can't enable posix ACLs. xattrs are disabled." + "\n"); + exit(1); + } + lo.use_statx = true; se = fuse_session_new(&args, &lo_oper, sizeof(lo_oper), &lo); |