commit e098446037da532d4a250efac9a813bc22f3669f

Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>

Date:   Mon Jan 24 08:55:53 2022 -0300

    linux: Fix ancillary 64-bit time timestamp conversion (BZ #28349, BZ#28350)

    The __convert_scm_timestamps only updates the control message last

    pointer for SOL_SOCKET type, so if the message control buffer contains

    multiple ancillary message types the converted timestamp one might

    overwrite a valid message.

    The test checks if the extra ancillary space is correctly handled

    by recvmsg/recvmmsg, where if there is no extra space for the 64-bit

    time_t converted message the control buffer should be marked with

    MSG_TRUNC.  It also check if recvmsg/recvmmsg handle correctly multiple

    ancillary data.

    Checked on x86_64-linux and on i686-linux-gnu on both 5.11 and

    4.15 kernel.

    Co-authored-by: Fabian Vogt <fvogt@suse.de>

    Reviewed-by: Florian Weimer <fweimer@redhat.com>

    (cherry picked from commit 8fba672472ae0055387e9315fc2eddfa6775ca79)

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile

index cdc01a3f023ec09a..7c75e22c6d0e9ff5 100644

--- a/sysdeps/unix/sysv/linux/Makefile

+++ b/sysdeps/unix/sysv/linux/Makefile

@@ -273,6 +273,9 @@ sysdep_routines += cmsg_nxthdr

 CFLAGS-recvmmsg.c = -fexceptions -fasynchronous-unwind-tables

 CFLAGS-sendmmsg.c = -fexceptions -fasynchronous-unwind-tables

+tests += tst-socket-timestamp

+tests-time64 += tst-socket-timestamp-time64

+

 tests-special += $(objpfx)tst-socket-consts.out

 $(objpfx)tst-socket-consts.out: ../sysdeps/unix/sysv/linux/tst-socket-consts.py

 	PYTHONPATH=../scripts \

diff --git a/sysdeps/unix/sysv/linux/convert_scm_timestamps.c b/sysdeps/unix/sysv/linux/convert_scm_timestamps.c

index 00c934c4135f0d42..5d3c4199e0b32944 100644

--- a/sysdeps/unix/sysv/linux/convert_scm_timestamps.c

+++ b/sysdeps/unix/sysv/linux/convert_scm_timestamps.c

@@ -54,6 +54,8 @@ __convert_scm_timestamps (struct msghdr *msg, socklen_t msgsize)

        cmsg != NULL;

        cmsg = CMSG_NXTHDR (msg, cmsg))

     {

+      last = cmsg;

+

       if (cmsg->cmsg_level != SOL_SOCKET)

 	continue;

@@ -75,11 +77,9 @@ __convert_scm_timestamps (struct msghdr *msg, socklen_t msgsize)

 	  tvts[1] = tmp[1];

 	  break;

 	}

-

-      last = cmsg;

     }

-  if (last == NULL || type == 0)

+  if (type == 0)

     return;

   if (CMSG_SPACE (sizeof tvts) > msgsize - msg->msg_controllen)

@@ -88,10 +88,12 @@ __convert_scm_timestamps (struct msghdr *msg, socklen_t msgsize)

       return;

     }

+  /* Zero memory for the new cmsghdr, so reading cmsg_len field

+     by CMSG_NXTHDR does not trigger UB.  */

+  memset (msg->msg_control + msg->msg_controllen, 0,

+	  CMSG_SPACE (sizeof tvts));

   msg->msg_controllen += CMSG_SPACE (sizeof tvts);

-  cmsg = CMSG_NXTHDR(msg, last);

-  if (cmsg == NULL)

-    return;

+  cmsg = CMSG_NXTHDR (msg, last);

   cmsg->cmsg_level = SOL_SOCKET;

   cmsg->cmsg_type = type;

   cmsg->cmsg_len = CMSG_LEN (sizeof tvts);

diff --git a/sysdeps/unix/sysv/linux/tst-socket-timestamp-time64.c b/sysdeps/unix/sysv/linux/tst-socket-timestamp-time64.c

new file mode 100644

index 0000000000000000..ae424c2a70026cf5

--- /dev/null

+++ b/sysdeps/unix/sysv/linux/tst-socket-timestamp-time64.c

@@ -0,0 +1 @@

+#include "tst-socket-timestamp.c"

diff --git a/sysdeps/unix/sysv/linux/tst-socket-timestamp.c b/sysdeps/unix/sysv/linux/tst-socket-timestamp.c

new file mode 100644

index 0000000000000000..9c2e76f7e27bd312

--- /dev/null

+++ b/sysdeps/unix/sysv/linux/tst-socket-timestamp.c

@@ -0,0 +1,336 @@

+/* Check recvmsg/recvmmsg 64-bit timestamp support.

+   Copyright (C) 2022 Free Software Foundation, Inc.

+   This file is part of the GNU C Library.

+

+   The GNU C Library is free software; you can redistribute it and/or

+   modify it under the terms of the GNU Lesser General Public

+   License as published by the Free Software Foundation; either

+   version 2.1 of the License, or (at your option) any later version.

+

+   The GNU C Library is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+   Lesser General Public License for more details.

+

+   You should have received a copy of the GNU Lesser General Public

+   License along with the GNU C Library; if not, see

+   <https://www.gnu.org/licenses/>.  */

+

+#include <array_length.h>

+#include <arpa/inet.h>

+#include <errno.h>

+#include <string.h>

+#include <stdio.h>

+#include <support/check.h>

+#include <support/next_to_fault.h>

+#include <support/support.h>

+#include <support/test-driver.h>

+#include <support/xunistd.h>

+#include <support/xsocket.h>

+#include <sys/mman.h>

+

+/* Some extra space added for ancillary data, it might be used to convert

+   32-bit timestamp to 64-bit for _TIME_BITS=64.  */

+enum { slack_max_size = 64 };

+static const int slack[] = { 0, 4, 8, 16, 32, slack_max_size };

+

+static bool support_64_timestamp;

+/* AF_INET socket and address used to receive data.  */

+static int srv;

+static struct sockaddr_in srv_addr;

+

+static int

+do_sendto (const struct sockaddr_in *addr, int nmsgs)

+{

+  int s = xsocket (AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);

+  xconnect (s, (const struct sockaddr *) addr, sizeof (*addr));

+

+  for (int i = 0; i < nmsgs; i++)

+    xsendto (s, &i, sizeof (i), 0, (const struct sockaddr *) addr,

+	     sizeof (*addr));

+

+  xclose (s);

+

+  return 0;

+}

+

+static void

+do_recvmsg_slack_ancillary (bool use_multi_call, int s, void *cmsg,

+			    size_t slack, size_t tsize, int exp_payload)

+{

+  int payload;

+  struct iovec iov =

+    {

+      .iov_base = &payload,

+      .iov_len = sizeof (payload)

+    };

+  size_t msg_controllen = CMSG_SPACE (tsize) + slack;

+  char *msg_control = cmsg - msg_controllen;

+  memset (msg_control, 0x55, msg_controllen);

+  struct mmsghdr mmhdr =

+    {

+      .msg_hdr =

+      {

+        .msg_name = NULL,

+        .msg_namelen = 0,

+        .msg_iov = &iov,

+        .msg_iovlen = 1,

+        .msg_control = msg_control,

+        .msg_controllen = msg_controllen

+      },

+    };

+

+  int r;

+  if (use_multi_call)

+    {

+      r = recvmmsg (s, &mmhdr, 1, 0, NULL);

+      if (r >= 0)

+	r = mmhdr.msg_len;

+    }

+  else

+    r = recvmsg (s, &mmhdr.msg_hdr, 0);

+  TEST_COMPARE (r, sizeof (int));

+  TEST_COMPARE (payload, exp_payload);

+

+  if (cmsg == NULL)

+    return;

+

+  /* A timestamp is expected if 32-bit timestamp are used (support in every

+     configuration) or if underlying kernel support 64-bit timestamps.

+     Otherwise recvmsg will need extra space do add the 64-bit timestamp.  */

+  bool exp_timestamp;

+  if (sizeof (time_t) == 4 || support_64_timestamp)

+    exp_timestamp = true;

+   else

+    exp_timestamp = slack >= CMSG_SPACE (tsize);

+

+  bool timestamp = false;

+  for (struct cmsghdr *cmsg = CMSG_FIRSTHDR (&mmhdr.msg_hdr);

+       cmsg != NULL;

+       cmsg = CMSG_NXTHDR (&mmhdr.msg_hdr, cmsg))

+    {

+      if (cmsg->cmsg_level != SOL_SOCKET)

+	continue;

+      if (cmsg->cmsg_type == SCM_TIMESTAMP

+	  && cmsg->cmsg_len == CMSG_LEN (sizeof (struct timeval)))

+	{

+	  struct timeval tv;

+	  memcpy (&tv, CMSG_DATA (cmsg), sizeof (tv));

+	  if (test_verbose)

+	    printf ("SCM_TIMESTAMP:   {%jd, %jd}\n", (intmax_t)tv.tv_sec,

+		    (intmax_t)tv.tv_usec);

+	  timestamp = true;

+	}

+      else if (cmsg->cmsg_type == SCM_TIMESTAMPNS

+	       && cmsg->cmsg_len == CMSG_LEN (sizeof (struct timespec)))

+	{

+	  struct timespec ts;

+	  memcpy (&ts, CMSG_DATA (cmsg), sizeof (ts));

+	  if (test_verbose)

+	    printf ("SCM_TIMESTAMPNS: {%jd, %jd}\n", (intmax_t)ts.tv_sec,

+		    (intmax_t)ts.tv_nsec);

+	  timestamp = true;

+	}

+    }

+

+  TEST_COMPARE (timestamp, exp_timestamp);

+}

+

+/* Check if the extra ancillary space is correctly handled by recvmsg and

+   recvmmsg with different extra space for the ancillaty buffer.  */

+static void

+do_test_slack_space (void)

+{

+  /* Setup the ancillary data buffer with an extra page with PROT_NONE to

+     check the possible timestamp conversion on some systems.  */

+  struct support_next_to_fault nf =

+    support_next_to_fault_allocate (slack_max_size);

+  void *msgbuf = nf.buffer + slack_max_size;

+

+  /* Enable the timestamp using struct timeval precision.  */

+  {

+    int r = setsockopt (srv, SOL_SOCKET, SO_TIMESTAMP, &(int){1},

+			sizeof (int));

+    TEST_VERIFY_EXIT (r != -1);

+  }

+  /* Check recvmsg.  */

+  do_sendto (&srv_addr, array_length (slack));

+  for (int s = 0; s < array_length (slack); s++)

+    {

+      memset (nf.buffer, 0x55, nf.length);

+      do_recvmsg_slack_ancillary (false, srv, msgbuf, slack[s],

+				  sizeof (struct timeval), s);

+    }

+  /* Check recvmmsg.  */

+  do_sendto (&srv_addr, array_length (slack));

+  for (int s = 0; s < array_length (slack); s++)

+    {

+      memset (nf.buffer, 0x55, nf.length);

+      do_recvmsg_slack_ancillary (true, srv, msgbuf, slack[s],

+				  sizeof (struct timeval), s);

+    }

+

+  /* Now enable timestamp using a higher precision, it overwrites the previous

+     precision.  */

+  {

+    int r = setsockopt (srv, SOL_SOCKET, SO_TIMESTAMPNS, &(int){1},

+			sizeof (int));

+    TEST_VERIFY_EXIT (r != -1);

+  }

+  /* Check recvmsg.  */

+  do_sendto (&srv_addr, array_length (slack));

+  for (int s = 0; s < array_length (slack); s++)

+    do_recvmsg_slack_ancillary (false, srv, msgbuf, slack[s],

+				sizeof (struct timespec), s);

+  /* Check recvmmsg.  */

+  do_sendto (&srv_addr, array_length (slack));

+  for (int s = 0; s < array_length (slack); s++)

+    do_recvmsg_slack_ancillary (true, srv, msgbuf, slack[s],

+				sizeof (struct timespec), s);

+

+  support_next_to_fault_free (&nf);

+}

+

+/* Check if the converted 64-bit timestamp is correctly appended when there

+   are multiple ancillary messages.  */

+static void

+do_recvmsg_multiple_ancillary (bool use_multi_call, int s, void *cmsg,

+			       size_t cmsgsize, int exp_msg)

+{

+  int msg;

+  struct iovec iov =

+    {

+      .iov_base = &msg,

+      .iov_len = sizeof (msg)

+    };

+  size_t msgs = cmsgsize;

+  struct mmsghdr mmhdr =

+    {

+      .msg_hdr =

+      {

+        .msg_name = NULL,

+        .msg_namelen = 0,

+        .msg_iov = &iov,

+        .msg_iovlen = 1,

+        .msg_controllen = msgs,

+        .msg_control = cmsg,

+      },

+    };

+

+  int r;

+  if (use_multi_call)

+    {

+      r = recvmmsg (s, &mmhdr, 1, 0, NULL);

+      if (r >= 0)

+	r = mmhdr.msg_len;

+    }

+  else

+    r = recvmsg (s, &mmhdr.msg_hdr, 0);

+  TEST_COMPARE (r, sizeof (int));

+  TEST_COMPARE (msg, exp_msg);

+

+  if (cmsg == NULL)

+    return;

+

+  bool timestamp = false;

+  bool origdstaddr = false;

+  for (struct cmsghdr *cmsg = CMSG_FIRSTHDR (&mmhdr.msg_hdr);

+       cmsg != NULL;

+       cmsg = CMSG_NXTHDR (&mmhdr.msg_hdr, cmsg))

+    {

+      if (cmsg->cmsg_level == SOL_IP

+	  && cmsg->cmsg_type == IP_ORIGDSTADDR

+	  && cmsg->cmsg_len >= CMSG_LEN (sizeof (struct sockaddr_in)))

+	{

+	  struct sockaddr_in sa;

+	  memcpy (&sa, CMSG_DATA (cmsg), sizeof (sa));

+	  if (test_verbose)

+	    {

+	      char str[INET_ADDRSTRLEN];

+	      inet_ntop (AF_INET, &sa.sin_addr, str, INET_ADDRSTRLEN);

+	      printf ("IP_ORIGDSTADDR:  %s:%d\n", str, ntohs (sa.sin_port));

+	    }

+	  origdstaddr = sa.sin_addr.s_addr == srv_addr.sin_addr.s_addr

+			&& sa.sin_port == srv_addr.sin_port;

+	}

+      if (cmsg->cmsg_level == SOL_SOCKET

+	  && cmsg->cmsg_type == SCM_TIMESTAMP

+	  && cmsg->cmsg_len >= CMSG_LEN (sizeof (struct timeval)))

+	{

+	  struct timeval tv;

+	  memcpy (&tv, CMSG_DATA (cmsg), sizeof (tv));

+	  if (test_verbose)

+	    printf ("SCM_TIMESTAMP:   {%jd, %jd}\n", (intmax_t)tv.tv_sec,

+		    (intmax_t)tv.tv_usec);

+	  timestamp = true;

+	}

+    }

+

+  TEST_COMPARE (timestamp, true);

+  TEST_COMPARE (origdstaddr, true);

+}

+

+static void

+do_test_multiple_ancillary (void)

+{

+  {

+    int r = setsockopt (srv, SOL_SOCKET, SO_TIMESTAMP, &(int){1},

+			sizeof (int));

+    TEST_VERIFY_EXIT (r != -1);

+  }

+  {

+    int r = setsockopt (srv, IPPROTO_IP, IP_RECVORIGDSTADDR, &(int){1},

+			sizeof (int));

+    TEST_VERIFY_EXIT (r != -1);

+  }

+

+  /* Enougth data for default SO_TIMESTAMP, the IP_RECVORIGDSTADDR, and the

+     extra 64-bit SO_TIMESTAMP.  */

+  enum { msgbuflen = CMSG_SPACE (2 * sizeof (uint64_t))

+		     + CMSG_SPACE (sizeof (struct sockaddr_in))

+		     + CMSG_SPACE (2 * sizeof (uint64_t)) };

+  char msgbuf[msgbuflen];

+

+  enum { nmsgs = 8 };

+  /* Check recvmsg.  */

+  do_sendto (&srv_addr, nmsgs);

+  for (int s = 0; s < nmsgs; s++)

+    do_recvmsg_multiple_ancillary (false, srv, msgbuf, msgbuflen, s);

+  /* Check recvmmsg.  */

+  do_sendto (&srv_addr, nmsgs);

+  for (int s = 0; s < nmsgs; s++)

+    do_recvmsg_multiple_ancillary (true, srv, msgbuf, msgbuflen, s);

+}

+

+static int

+do_test (void)

+{

+  srv = xsocket (AF_INET, SOCK_DGRAM, 0);

+  srv_addr = (struct sockaddr_in) {

+    .sin_family = AF_INET,

+    .sin_addr = {.s_addr = htonl (INADDR_LOOPBACK) },

+  };

+  xbind (srv, (struct sockaddr *) &srv_addr, sizeof (srv_addr));

+  {

+    socklen_t sa_len = sizeof (srv_addr);

+    xgetsockname (srv, (struct sockaddr *) &srv_addr, &sa_len);

+    TEST_VERIFY (sa_len == sizeof (srv_addr));

+  }

+

+  TEST_COMPARE (recvmsg (-1, NULL, 0), -1);

+  TEST_COMPARE (errno, EBADF);

+  TEST_COMPARE (recvmmsg (-1, NULL, 0, 0, NULL), -1);

+  TEST_COMPARE (errno, EBADF);

+

+  /* If underlying kernel does not support   */

+  support_64_timestamp = support_socket_so_timestamp_time64 (srv);

+

+  do_test_slack_space ();

+  do_test_multiple_ancillary ();

+

+  xclose (srv);

+

+  return 0;

+}

+

+#include <support/test-driver.c>