Tenant Isolation

build/patches/nginx-1.31.2-tenant-isolation.patch

@@ -139,7 +139,7 @@
      ngx_memzero(&of, sizeof(ngx_open_file_info_t));
  
      of.read_ahead = clcf->read_ahead;
-@@ -278,6 +384,242 @@
+@@ -278,6 +384,231 @@
  }
  
  
@@ -213,14 +213,9 @@
 +        croot = slcf->tenant_isolation_root;
 +
 +        /*
-+         * Require a path-separator boundary immediately after the prefix, so a
++         * Require '/' (or end) right after the prefix so root "/home/u1" is not
-+         * docroot that merely shares a string prefix with the confinement root
++         * treated as a parent of "/home/u10/..." (would fail open). Length checked
-+         * (root "/home/u1" vs docroot "/home/u10/...") is not mistaken for being
++         * first to keep the read in bounds; a root ending in '/' implies it.
-+         * inside it -- otherwise `rel` would be computed against the wrong root
-+         * and the check would silently no-op (fail open). If the configured root
-+         * itself ends in '/', that boundary is already implied. The length guard
-+         * is evaluated first so the path->data[croot.len] read stays in bounds
-+         * (path->data is NUL-terminated at path->len).
 +         */
 +        if (path->len < croot.len
 +            || ngx_strncmp(path->data, croot.data, croot.len) != 0
@@ -301,10 +296,8 @@
 +    case ENFILE:
 +    case ENOMEM:
 +    case ESTALE:
-+        /* Not an escape verdict: a permission, fd/memory-exhaustion or stale-NFS
++        /* Not an escape: perm / fd exhaustion / stale NFS. Let nginx's own open
-+         * condition that stopped resolution before it could conclude. Let nginx's
++         * surface the real 403/500/503 instead of masking it as a 403. */
-+         * own open run so it surfaces the correct 403/500/503 rather than masking
-+         * it (or a transient hiccup) as a tenant_isolation 403. */
 +        return NGX_OK;
 +
 +    case EXDEV:   /* RESOLVE_BENEATH: resolution would escape the root */
@@ -318,11 +311,9 @@
 +    case EOPNOTSUPP:
 +    case EPERM:
 +    case EINVAL:
-+        /* openat2 unavailable or rejecting our resolve flags (old kernel, a
++        /* openat2 unavailable or rejecting our flags (old kernel / seccomp, e.g.
-+         * seccomp filter that ENOSYS/EPERMs it -- e.g. a hardened systemd unit --
++         * RestrictSUIDSGID). Latch to the realpath fallback instead of failing
-+         * or a kernel that predates RESOLVE_BENEATH). Latch and use the realpath
++         * open or 403-ing every request. */
-+         * containment check from now on rather than failing open or 403-ing every
-+         * request. */
 +        if (!openat2_unavailable) {
 +            openat2_unavailable = 1;
 +            ngx_log_error(NGX_LOG_WARN, r->connection->log, err,
@@ -334,10 +325,8 @@
 +        return ngx_http_static_tenant_check_realpath(r, root_buf, path);
 +
 +    default:
-+        /* Unexpected errno from openat2. Fail CLOSED: an escape we have no named
++        /* Unexpected errno: fail closed. Benign non-escape errnos are handled
-+         * case for must not be served. Benign resource/permission errnos that
++         * above, so treat anything here as a possible escape. */
-+         * genuinely mean "not an escape" are enumerated above, so reaching here
-+         * is anomalous -- deny and log rather than fall through to nginx. */
 +        ngx_log_error(NGX_LOG_ERR, r->connection->log, err,
 +                      "tenant_isolation: openat2 failed with an unexpected error "
 +                      "for \"%V\", denying", path);

build/raccoon.sh

@@ -244,18 +244,19 @@ function clean_install() {
         cd /opt/mod/; git clone --recurse-submodules https://github.com/wargio/naxsi.git naxsi
     fi
 
-    # NGX_MOD_ZSTD — Zstandard compression module from eilandert (maintained
+    # zstd module from https://github.com/theraw/zstd-nginx-module (NGX_MOD_ZSTD =
-    # fork of tokers/zstd-nginx-module, which has been abandoned since 0.1.1 in
+    # git tag). Extract with --strip-components=1 into a fixed local dir name so the
-    # 2023-10-23). Pinned via NGX_MOD_ZSTD; tarball pattern (dir name embeds
+    # --add-module path never depends on the archive's top folder; guard on config
-    # version → cache invalidates automatically when the pin moves).
+    # so a partial extract re-fetches.
-    #
+    if [ ! -f /opt/mod/zstd-nginx-module-${NGX_MOD_ZSTD}/config ]; then
-    # The fork ships the flush-loop CPU-spin fix we previously carried as
+        cd /opt/mod/
-    # build/patches/zstd-nginx-module-0.1.1-flush-cpu-spin.patch — see PR #23,
+        rm -rf zstd-nginx-module-${NGX_MOD_ZSTD}
-    # PR #49, and the "content-less flush completed" branch in
+        wget -O zstd-nginx-module-${NGX_MOD_ZSTD}.tar.gz \
-    # filter/ngx_http_zstd_filter_module.c. No local patching needed.
+            https://github.com/theraw/zstd-nginx-module/archive/refs/tags/${NGX_MOD_ZSTD}.tar.gz
-    if [ ! -d /opt/mod/zstd-nginx-module-${NGX_MOD_ZSTD} ]; then
+        mkdir -p zstd-nginx-module-${NGX_MOD_ZSTD}
-        cd /opt/mod/; wget https://github.com/eilandert/zstd-nginx-module/archive/refs/tags/${NGX_MOD_ZSTD}.tar.gz
+        tar xf zstd-nginx-module-${NGX_MOD_ZSTD}.tar.gz \
-        cd /opt/mod/; tar xf ${NGX_MOD_ZSTD}.tar.gz; rm -Rf ${NGX_MOD_ZSTD}.tar.gz
+            -C zstd-nginx-module-${NGX_MOD_ZSTD} --strip-components=1
+        rm -Rf zstd-nginx-module-${NGX_MOD_ZSTD}.tar.gz
     fi
 
     # END OF NGINX MODULES

build/trixie.sh

@@ -244,18 +244,19 @@ function clean_install() {
         cd /opt/mod/; git clone --recurse-submodules https://github.com/wargio/naxsi.git naxsi
     fi
 
-    # NGX_MOD_ZSTD — Zstandard compression module from eilandert (maintained
+    # zstd module from https://github.com/theraw/zstd-nginx-module (NGX_MOD_ZSTD =
-    # fork of tokers/zstd-nginx-module, which has been abandoned since 0.1.1 in
+    # git tag). Extract with --strip-components=1 into a fixed local dir name so the
-    # 2023-10-23). Pinned via NGX_MOD_ZSTD; tarball pattern (dir name embeds
+    # --add-module path never depends on the archive's top folder; guard on config
-    # version → cache invalidates automatically when the pin moves).
+    # so a partial extract re-fetches.
-    #
+    if [ ! -f /opt/mod/zstd-nginx-module-${NGX_MOD_ZSTD}/config ]; then
-    # The fork ships the flush-loop CPU-spin fix we previously carried as
+        cd /opt/mod/
-    # build/patches/zstd-nginx-module-0.1.1-flush-cpu-spin.patch — see PR #23,
+        rm -rf zstd-nginx-module-${NGX_MOD_ZSTD}
-    # PR #49, and the "content-less flush completed" branch in
+        wget -O zstd-nginx-module-${NGX_MOD_ZSTD}.tar.gz \
-    # filter/ngx_http_zstd_filter_module.c. No local patching needed.
+            https://github.com/theraw/zstd-nginx-module/archive/refs/tags/${NGX_MOD_ZSTD}.tar.gz
-    if [ ! -d /opt/mod/zstd-nginx-module-${NGX_MOD_ZSTD} ]; then
+        mkdir -p zstd-nginx-module-${NGX_MOD_ZSTD}
-        cd /opt/mod/; wget https://github.com/eilandert/zstd-nginx-module/archive/refs/tags/${NGX_MOD_ZSTD}.tar.gz
+        tar xf zstd-nginx-module-${NGX_MOD_ZSTD}.tar.gz \
-        cd /opt/mod/; tar xf ${NGX_MOD_ZSTD}.tar.gz; rm -Rf ${NGX_MOD_ZSTD}.tar.gz
+            -C zstd-nginx-module-${NGX_MOD_ZSTD} --strip-components=1
+        rm -Rf zstd-nginx-module-${NGX_MOD_ZSTD}.tar.gz
     fi
 
     # END OF NGINX MODULES

static/nginx/nginx.conf

@@ -59,19 +59,10 @@ http {
     open_file_cache_min_uses       2;
     open_file_cache_errors         on;
 
-    # Symlink backstop for tenant static files. Enforced by nginx at the SAME
+    # Symlink backstop for tenant_isolation, checked at the serving open(): catches
-    # open() that serves the file, so it complements the tenant_isolation patch
+    # the probe->open race and the paths the patch skips (gzip_static, autoindex,
-    # (docs/tenant-isolation.md) on the axes that patch cannot cover from its
+    # dav, mp4/flv). if_not_owner allows a tenant's own symlinks, blocks ones whose
-    # separate openat2 probe:
+    # target has a different owner (docroot/x -> /etc/passwd => 403).
-    #   * the probe->open TOCTOU window — a tenant that swaps a benign file for an
-    #     escaping symlink after the probe is still caught here, at serve time;
-    #   * the open paths the patch does not intercept — gzip_static, autoindex,
-    #     dav, mp4/flv — which all funnel through this same disable_symlinks check.
-    # `if_not_owner` (not `on`) is deliberate: it permits a tenant's OWN in-tree
-    # symlinks (e.g. Laravel's public/storage) while refusing a symlink whose
-    # target has a different owner (docroot/x -> /etc/passwd, root-owned => 403),
-    # which matches the tenant_isolation semantics. `from=$document_root` skips
-    # symlink checks on the docroot prefix itself (owned by the platform).
     disable_symlinks               if_not_owner from=$document_root;
 
     # ===================== TLS ============================ #

version

@@ -55,15 +55,7 @@ export NGX_MOD_LUA_LOCK="0.09"
 export NGX_MOD_LUA_SRCACHE="0.33"
 
 # https://github.com/eilandert/zstd-nginx-module/tags
-# Zstandard compression module. Chrome 123+ and Firefox 126+ send
+export NGX_MOD_ZSTD="v1.1"
-# `Accept-Encoding: zstd`; older clients fall back to brotli/gzip.
-# Switched from tokers/zstd-nginx-module (unmaintained since 0.1.1, 2023-10-23)
-# to eilandert/zstd-nginx-module, an actively maintained fork that has already
-# absorbed the flush-loop CPU-spin fix we previously carried as a local patch
-# (PR #23 + PR #49 + follow-up work — see filter/ngx_http_zstd_filter_module.c
-# in the fork for the "content-less flush completed" branch that supersedes
-# our patch).
-export NGX_MOD_ZSTD="0.90.6"
 
 # https://github.com/zlib-ng/zlib-ng/releases
 # Drop-in libz replacement with SIMD-accelerated DEFLATE. Built in --zlib-compat