Snap for 6838321 from be4e18d619edcc8f09534a4ec84428cf23b09a13 to mainline-releaser_aml_301500702android-mainline-12.0.0_r55android-mainline-11.0.0_r9android-mainline-11.0.0_r8android-mainline-11.0.0_r7android-mainline-11.0.0_r6android-mainline-11.0.0_r5android-mainline-11.0.0_r45android-mainline-11.0.0_r4android-mainline-11.0.0_r33android-mainline-11.0.0_r3android-mainline-11.0.0_r29android-mainline-11.0.0_r19android-mainline-11.0.0_r10android11-mainline-sparse-2021-jan-releaseandroid11-mainline-sparse-2020-dec-releaseandroid11-mainline-release

Change-Id: Iaf330670367c7004be4cf5c1201774de9c97030c

3 files changed, 33 insertions, 6 deletions

diff --git a/libc/bionic/ifaddrs.cpp b/libc/bionic/ifaddrs.cpp
index e89b0bf11..153633353 100644
--- a/libc/bionic/ifaddrs.cpp
+++ b/libc/bionic/ifaddrs.cpp
@@ -28,6 +28,7 @@
 
 #include <ifaddrs.h>
 
+#include <async_safe/log.h>
 #include <cutils/misc.h>           // FIRST_APPLICATION_UID
 #include <errno.h>
 #include <linux/if_packet.h>
@@ -205,12 +206,12 @@ static void __getifaddrs_callback(void* context, nlmsghdr* hdr) {
     new_addr->interface_index = static_cast<int>(msg->ifa_index);
 
     // If this is a known interface, copy what we already know.
+    // If we don't know about this interface yet, we try to resolve the name and flags using ioctl
+    // calls during postprocessing.
     if (known_addr != nullptr) {
       strcpy(new_addr->name, known_addr->name);
       new_addr->ifa.ifa_name = new_addr->name;
       new_addr->ifa.ifa_flags = known_addr->ifa.ifa_flags;
-    } else {
-      new_addr->ifa.ifa_flags = msg->ifa_flags;
     }
 
     // Go through the various bits of information and find the name, address
@@ -271,10 +272,34 @@ static void resolve_or_remove_nameless_interfaces(ifaddrs** list) {
     } else {
       prev_addr = addr;
     }
+
     addr = reinterpret_cast<ifaddrs_storage*>(next_addr);
   }
 }
 
+static void get_interface_flags_via_ioctl(ifaddrs** list) {
+  ScopedFd s(socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0));
+  if (s.get() == -1) {
+    async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+                          "socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC) failed in ifaddrs: %s",
+                          strerror(errno));
+    return;
+  }
+
+  for (ifaddrs_storage* addr = reinterpret_cast<ifaddrs_storage*>(*list); addr != nullptr;
+       addr = reinterpret_cast<ifaddrs_storage*>(addr->ifa.ifa_next)) {
+    ifreq ifr = {};
+    strlcpy(ifr.ifr_name, addr->ifa.ifa_name, sizeof(ifr.ifr_name));
+    if (ioctl(s.get(), SIOCGIFFLAGS, &ifr) != -1) {
+      addr->ifa.ifa_flags = ifr.ifr_flags;
+    } else {
+      async_safe_format_log(ANDROID_LOG_ERROR, "libc",
+                            "ioctl(SIOCGIFFLAGS) for \"%s\" failed in ifaddrs: %s",
+                            addr->ifa.ifa_name, strerror(errno));
+    }
+  }
+}
+
 int getifaddrs(ifaddrs** out) {
   // We construct the result directly into `out`, so terminate the list.
   *out = nullptr;
@@ -303,6 +328,9 @@ int getifaddrs(ifaddrs** out) {
     // If we weren't able to depend on GETLINK messages, it's possible some
     // interfaces never got their name set. Resolve them using if_indextoname or remove them.
     resolve_or_remove_nameless_interfaces(out);
+    // Similarly, without GETLINK messages, interfaces will not have their flags set.
+    // Resolve them using the SIOCGIFFLAGS ioctl call.
+    get_interface_flags_via_ioctl(out);
   }
 
   return 0;
diff --git a/libc/dns/resolv/res_send.c b/libc/dns/resolv/res_send.c
index a645a6b4a..fa81e6dc5 100644
--- a/libc/dns/resolv/res_send.c
+++ b/libc/dns/resolv/res_send.c
@@ -948,6 +948,8 @@ send_vc(res_state statp, struct __res_params* params,
 			else
 				break;
 		}
+		// return size should never exceed container size
+		resplen = anssiz;
 	}
 	/*
 	 * If the calling applicating has bailed out of
@@ -960,7 +962,7 @@ send_vc(res_state statp, struct __res_params* params,
 		DprintQ((statp->options & RES_DEBUG) ||
 			(statp->pfcode & RES_PRF_REPLY),
 			(stdout, ";; old answer (unexpected):\n"),
-			ans, (resplen > anssiz) ? anssiz: resplen);
+			ans, resplen);
 		goto read_len;
 	}
 
diff --git a/tests/cfi_test.cpp b/tests/cfi_test.cpp
index 792f917b2..e0ae3afc7 100644
--- a/tests/cfi_test.cpp
+++ b/tests/cfi_test.cpp
@@ -95,9 +95,6 @@ TEST(cfi_test, basic) {
   EXPECT_EQ(get_global_address(), get_last_address());
   EXPECT_EQ(c, get_count());
 
-  // CFI check for a stack address. This is always invalid and gets the process killed.
-  EXPECT_DEATH(__cfi_slowpath(45, reinterpret_cast<void*>(&c)), "");
-
   // CFI check for a heap address.
   // It's possible that this allocation could wind up in the same CFI granule as
   // an unchecked library, which means the below might not crash. To force a