Don't buffer IPT_SO_SET_REPLACE syscalls because that doesn't work

rr-debugger · Dec 26, 2023 · b8e921f · b8e921f
1 parent 2fdc856
commit b8e921f
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Showing 3 changed files with 35 additions and 24 deletions.
diff --git a/src/kernel_supplement.h b/src/kernel_supplement.h
@@ -277,8 +277,11 @@ struct rr_input_mask {
 
 // Defined in the ip_tables header for each protocol, but always to the same,
 // value, so it should be fine to set this here
-#ifndef SO_SET_REPLACE
-#define SO_SET_REPLACE 64
+#ifndef IPT_SO_SET_REPLACE
+#define IPT_SO_SET_REPLACE 64
+#endif
+#ifndef IPV6T_SO_SET_REPLACE
+#define IPV6T_SO_SET_REPLACE 64
 #endif
 
 #ifndef HCIGETDEVLIST

diff --git a/src/preload/syscallbuf.c b/src/preload/syscallbuf.c
@@ -111,6 +111,19 @@ struct btrfs_ioctl_clone_range_args {
 #define GRND_NONBLOCK 1
 #endif
 
+#ifndef SOL_IP
+#define SOL_IP 0
+#endif
+#ifndef SOL_IPV6
+#define SOL_IPV6 41
+#endif
+#ifndef IPT_SO_SET_REPLACE
+#define IPT_SO_SET_REPLACE 64
+#endif
+#ifndef IPV6T_SO_SET_REPLACE
+#define IPV6T_SO_SET_REPLACE 64
+#endif
+
 struct rr_rseq {
   uint32_t cpu_id_start;
   uint32_t cpu_id;
@@ -3395,6 +3408,11 @@ static long sys_setsockopt(struct syscall_info* call) {
     // Let rr intercept this (and probably disable it)
     return traced_raw_syscall(call);
   }
+  if ((level == SOL_IP && optname == IPT_SO_SET_REPLACE) ||
+      (level == SOL_IPV6 && optname == IPV6T_SO_SET_REPLACE)) {
+    // Let rr intercept this because it has output parameters :-(
+    return traced_raw_syscall(call);
+  }
 
   void* ptr = prep_syscall_for_fd(sockfd);
   long ret;

diff --git a/src/record_syscall.cc b/src/record_syscall.cc
@@ -976,28 +976,18 @@ static Switchable prepare_setsockopt(RecordTask* t,
     r.set_arg1(-1);
     t->set_regs(r);
   } else {
-    switch (args.level) {
-      case SOL_IP:
-      case SOL_IPV6:
-        switch (args.optname) {
-          case SO_SET_REPLACE: {
-            if (args.optlen < (ssize_t)sizeof(typename Arch::ipt_replace)) {
-              break;
-            }
-            auto repl_ptr =
-                args.optval.rptr().template cast<typename Arch::ipt_replace>();
-            syscall_state.mem_ptr_parameter(
-                REMOTE_PTR_FIELD(repl_ptr, counters),
-                t->read_mem(REMOTE_PTR_FIELD(repl_ptr, num_counters)) *
-                    sizeof(typename Arch::xt_counters));
-            break;
-          }
-          default:
-            break;
-        }
-        break;
-      default:
-        break;
+    if (args.level == SOL_IP && args.optname == IPT_SO_SET_REPLACE) {
+      if (args.optlen < (ssize_t)sizeof(typename Arch::ipt_replace)) {
+        return PREVENT_SWITCH;
+      }
+      auto repl_ptr =
+          args.optval.rptr().template cast<typename Arch::ipt_replace>();
+      syscall_state.mem_ptr_parameter(
+          REMOTE_PTR_FIELD(repl_ptr, counters),
+          t->read_mem(REMOTE_PTR_FIELD(repl_ptr, num_counters)) *
+              sizeof(typename Arch::xt_counters));
+    } else if (args.level == SOL_IPV6 && args.optname == IPV6T_SO_SET_REPLACE) {
+      FATAL() << "IPV6T_SO_SET_REPLACE not supported yet";
     }
   }
   return PREVENT_SWITCH;