grpc: fix CVE-2023-33953

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

2 files changed, 225 insertions, 0 deletions

diff --git a/meta-oe/recipes-devtools/grpc/grpc/0001-backport-iomgr-EventEngine-Improve-server-handling-o.patch b/meta-oe/recipes-devtools/grpc/grpc/0001-backport-iomgr-EventEngine-Improve-server-handling-o.patch
new file mode 100644
index 0000000000..4488df172f
--- /dev/null
+++ b/meta-oe/recipes-devtools/grpc/grpc/0001-backport-iomgr-EventEngine-Improve-server-handling-o.patch
@@ -0,0 +1,224 @@
+From b3c105c59dfb7d932b36b0d9ac7ab62875ab23e8 Mon Sep 17 00:00:00 2001
+From: AJ Heller <hork@google.com>
+Date: Wed, 12 Jul 2023 18:42:09 -0700
+Subject: [PATCH] [backport][iomgr][EventEngine] Improve server handling of
+ file descriptor exhaustion (#33672)
+
+Backport of #33656
+
+CVE: CVE-2023-33953
+
+Upstream-Status: Backport [1e86ca5834b94cae7d5e6d219056c0fc895cf95d]
+The patch is backported with tweaks to fit 1.50.1.
+
+Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
+---
+ .../event_engine/posix_engine/posix_engine.h  |  1 +
+ src/core/lib/iomgr/tcp_server_posix.cc        | 51 ++++++++++++++-----
+ src/core/lib/iomgr/tcp_server_utils_posix.h   | 14 ++++-
+ .../iomgr/tcp_server_utils_posix_common.cc    | 22 ++++++++
+ 4 files changed, 73 insertions(+), 15 deletions(-)
+
+diff --git a/src/core/lib/event_engine/posix_engine/posix_engine.h b/src/core/lib/event_engine/posix_engine/posix_engine.h
+index eac6dfb4c5..866c04bcfa 100644
+--- a/src/core/lib/event_engine/posix_engine/posix_engine.h
++++ b/src/core/lib/event_engine/posix_engine/posix_engine.h
+@@ -97,6 +97,7 @@ class PosixEventEngine final : public EventEngine {
+       const DNSResolver::ResolverOptions& options) override;
+   void Run(Closure* closure) override;
+   void Run(absl::AnyInvocable<void()> closure) override;
++  // Caution!! The timer implementation cannot create any fds. See #20418.
+   TaskHandle RunAfter(Duration when, Closure* closure) override;
+   TaskHandle RunAfter(Duration when,
+                       absl::AnyInvocable<void()> closure) override;
+diff --git a/src/core/lib/iomgr/tcp_server_posix.cc b/src/core/lib/iomgr/tcp_server_posix.cc
+index d43113fb03..32be997cff 100644
+--- a/src/core/lib/iomgr/tcp_server_posix.cc
++++ b/src/core/lib/iomgr/tcp_server_posix.cc
+@@ -16,13 +16,17 @@
+  *
+  */
+ 
+-/* FIXME: "posix" files shouldn't be depending on _GNU_SOURCE */
++#include <grpc/support/port_platform.h>
++
++#include <utility>
++
++#include <grpc/support/atm.h>
++
++// FIXME: "posix" files shouldn't be depending on _GNU_SOURCE
+ #ifndef _GNU_SOURCE
+ #define _GNU_SOURCE
+ #endif
+ 
+-#include <grpc/support/port_platform.h>
+-
+ #include "src/core/lib/iomgr/port.h"
+ 
+ #ifdef GRPC_POSIX_SOCKET_TCP_SERVER
+@@ -44,6 +48,7 @@
+ #include "absl/strings/str_format.h"
+ 
+ #include <grpc/event_engine/endpoint_config.h>
++#include <grpc/event_engine/event_engine.h>
+ #include <grpc/support/alloc.h>
+ #include <grpc/support/log.h>
+ #include <grpc/support/sync.h>
+@@ -63,6 +68,8 @@
+ #include "src/core/lib/resource_quota/api.h"
+ 
+ static std::atomic<int64_t> num_dropped_connections{0};
++static constexpr grpc_core::Duration kRetryAcceptWaitTime{
++    grpc_core::Duration::Seconds(1)};
+ 
+ using ::grpc_event_engine::experimental::EndpointConfig;
+ 
+@@ -195,21 +202,35 @@ static void on_read(void* arg, grpc_error_handle err) {
+     if (fd < 0) {
+       if (errno == EINTR) {
+         continue;
+-      } else if (errno == EAGAIN || errno == ECONNABORTED ||
+-                 errno == EWOULDBLOCK) {
++      }
++      // When the process runs out of fds, accept4() returns EMFILE. When this
++      // happens, the connection is left in the accept queue until either a
++      // read event triggers the on_read callback, or time has passed and the
++      // accept should be re-tried regardless. This callback is not cancelled,
++      // so a spurious wakeup may occur even when there's nothing to accept.
++      // This is not a performant code path, but if an fd limit has been
++      // reached, the system is likely in an unhappy state regardless.
++      if (errno == EMFILE) {
+         grpc_fd_notify_on_read(sp->emfd, &sp->read_closure);
++        if (gpr_atm_full_xchg(&sp->retry_timer_armed, true)) return;
++        grpc_timer_init(&sp->retry_timer,
++                        grpc_core::Timestamp::Now() + kRetryAcceptWaitTime,
++                        &sp->retry_closure);
+         return;
++      }
++      if (errno == EAGAIN || errno == ECONNABORTED || errno == EWOULDBLOCK) {
++        grpc_fd_notify_on_read(sp->emfd, &sp->read_closure);
++        return;
++      }
++      gpr_mu_lock(&sp->server->mu);
++      if (!sp->server->shutdown_listeners) {
++        gpr_log(GPR_ERROR, "Failed accept4: %s", strerror(errno));
+       } else {
+-        gpr_mu_lock(&sp->server->mu);
+-        if (!sp->server->shutdown_listeners) {
+-          gpr_log(GPR_ERROR, "Failed accept4: %s", strerror(errno));
+-        } else {
+-          /* if we have shutdown listeners, accept4 could fail, and we
+-             needn't notify users */
+-        }
+-        gpr_mu_unlock(&sp->server->mu);
+-        goto error;
++        // if we have shutdown listeners, accept4 could fail, and we
++        // needn't notify users
+       }
++      gpr_mu_unlock(&sp->server->mu);
++      goto error;
+     }
+ 
+     if (sp->server->memory_quota->IsMemoryPressureHigh()) {
+@@ -403,6 +424,7 @@ static grpc_error_handle clone_port(grpc_tcp_listener* listener,
+     sp->port_index = listener->port_index;
+     sp->fd_index = listener->fd_index + count - i;
+     GPR_ASSERT(sp->emfd);
++    grpc_tcp_server_listener_initialize_retry_timer(sp);
+     while (listener->server->tail->next != nullptr) {
+       listener->server->tail = listener->server->tail->next;
+     }
+@@ -575,6 +597,7 @@ static void tcp_server_shutdown_listeners(grpc_tcp_server* s) {
+   if (s->active_ports) {
+     grpc_tcp_listener* sp;
+     for (sp = s->head; sp; sp = sp->next) {
++      grpc_timer_cancel(&sp->retry_timer);
+       grpc_fd_shutdown(sp->emfd,
+                        GRPC_ERROR_CREATE_FROM_STATIC_STRING("Server shutdown"));
+     }
+diff --git a/src/core/lib/iomgr/tcp_server_utils_posix.h b/src/core/lib/iomgr/tcp_server_utils_posix.h
+index 94faa2c17e..2e78ce555f 100644
+--- a/src/core/lib/iomgr/tcp_server_utils_posix.h
++++ b/src/core/lib/iomgr/tcp_server_utils_posix.h
+@@ -25,6 +25,7 @@
+ #include "src/core/lib/iomgr/resolve_address.h"
+ #include "src/core/lib/iomgr/socket_utils_posix.h"
+ #include "src/core/lib/iomgr/tcp_server.h"
++#include "src/core/lib/iomgr/timer.h"
+ #include "src/core/lib/resource_quota/memory_quota.h"
+ 
+ /* one listening port */
+@@ -47,6 +48,11 @@ typedef struct grpc_tcp_listener {
+      identified while iterating through 'next'. */
+   struct grpc_tcp_listener* sibling;
+   int is_sibling;
++  // If an accept4() call fails, a timer is started to drain the accept queue in
++  // case no further connection attempts reach the gRPC server.
++  grpc_closure retry_closure;
++  grpc_timer retry_timer;
++  gpr_atm retry_timer_armed;
+ } grpc_tcp_listener;
+ 
+ /* the overall server */
+@@ -126,4 +132,10 @@ grpc_error_handle grpc_tcp_server_prepare_socket(
+ /* Ruturn true if the platform supports ifaddrs */
+ bool grpc_tcp_server_have_ifaddrs(void);
+ 
+-#endif /* GRPC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H */
++// Initialize (but don't start) the timer and callback to retry accept4() on a
++// listening socket after file descriptors have been exhausted. This must be
++// called when creating a new listener.
++void grpc_tcp_server_listener_initialize_retry_timer(
++    grpc_tcp_listener* listener);
++
++#endif  // GRPC_SRC_CORE_LIB_IOMGR_TCP_SERVER_UTILS_POSIX_H
+diff --git a/src/core/lib/iomgr/tcp_server_utils_posix_common.cc b/src/core/lib/iomgr/tcp_server_utils_posix_common.cc
+index 73a6b943ec..0e671c6485 100644
+--- a/src/core/lib/iomgr/tcp_server_utils_posix_common.cc
++++ b/src/core/lib/iomgr/tcp_server_utils_posix_common.cc
+@@ -18,6 +18,8 @@
+ 
+ #include <grpc/support/port_platform.h>
+ 
++#include <grpc/support/atm.h>
++
+ #include "src/core/lib/iomgr/port.h"
+ 
+ #ifdef GRPC_POSIX_SOCKET_TCP_SERVER_UTILS_COMMON
+@@ -80,6 +82,24 @@ static int get_max_accept_queue_size(void) {
+   return s_max_accept_queue_size;
+ }
+ 
++static void listener_retry_timer_cb(void* arg, grpc_error_handle err) {
++  // Do nothing if cancelled.
++  if (!err.ok()) return;
++  grpc_tcp_listener* listener = static_cast<grpc_tcp_listener*>(arg);
++  gpr_atm_no_barrier_store(&listener->retry_timer_armed, false);
++  if (!grpc_fd_is_shutdown(listener->emfd)) {
++    grpc_fd_set_readable(listener->emfd);
++  }
++}
++
++void grpc_tcp_server_listener_initialize_retry_timer(
++    grpc_tcp_listener* listener) {
++  gpr_atm_no_barrier_store(&listener->retry_timer_armed, false);
++  grpc_timer_init_unset(&listener->retry_timer);
++  GRPC_CLOSURE_INIT(&listener->retry_closure, listener_retry_timer_cb, listener,
++                    grpc_schedule_on_exec_ctx);
++}
++
+ static grpc_error_handle add_socket_to_server(grpc_tcp_server* s, int fd,
+                                               const grpc_resolved_address* addr,
+                                               unsigned port_index,
+@@ -112,6 +132,8 @@ static grpc_error_handle add_socket_to_server(grpc_tcp_server* s, int fd,
+   sp->server = s;
+   sp->fd = fd;
+   sp->emfd = grpc_fd_create(fd, name.c_str(), true);
++  grpc_tcp_server_listener_initialize_retry_timer(sp);
++
+   memcpy(&sp->addr, addr, sizeof(grpc_resolved_address));
+   sp->port = port;
+   sp->port_index = port_index;
+-- 
+2.34.1
+
diff --git a/meta-oe/recipes-devtools/grpc/grpc_1.50.1.bb b/meta-oe/recipes-devtools/grpc/grpc_1.50.1.bb
index b3956ce40c..3cfd0210db 100644
--- a/meta-oe/recipes-devtools/grpc/grpc_1.50.1.bb
+++ b/meta-oe/recipes-devtools/grpc/grpc_1.50.1.bb
@@ -27,6 +27,7 @@ SRC_URI = "gitsm://github.com/grpc/grpc.git;protocol=https;name=grpc;branch=${BR
            file://0001-cmake-add-separate-export-for-plugin-targets.patch \
            file://0001-cmake-Link-with-libatomic-on-rv32-rv64.patch \
            file://0001-fix-CVE-2023-32732.patch \
+           file://0001-backport-iomgr-EventEngine-Improve-server-handling-o.patch \
            "
 # Fixes build with older compilers 4.8 especially on ubuntu 14.04
 CXXFLAGS:append:class-native = " -Wl,--no-as-needed"