commit 489d0b8b32548bc569cd3067aebf98b030720753

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

Date:   Thu Jan 27 16:45:18 2022 -0300

    Linux: Only generate 64 bit timestamps for 64 bit time_t recvmsg/recvmmsg

    The timestamps created by __convert_scm_timestamps only make sense for

    64 bit time_t programs, 32 bit time_t programs will ignore 64 bit time_t

    timestamps since SO_TIMESTAMP will be defined to old values (either by

    glibc or kernel headers).

    Worse, if the buffer is not suffice MSG_CTRUNC is set to indicate it

    (which breaks some programs [1]).

    This patch makes only 64 bit time_t recvmsg and recvmmsg to call

    __convert_scm_timestamps.  Also, the assumption to called it is changed

    from __ASSUME_TIME64_SYSCALLS to __TIMESIZE != 64 since the setsockopt

    might be called by libraries built without __TIME_BITS=64.  The

    MSG_CTRUNC is only set for the 64 bit symbols, it should happen only

    if 64 bit time_t programs run older kernels.

    Checked on x86_64-linux-gnu and i686-linux-gnu.

    [1] https://github.com/systemd/systemd/pull/20567

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

    (cherry picked from commit 948ce73b31fdb0860bcec4b8e62b14e88234f98a)

diff --git a/include/sys/socket.h b/include/sys/socket.h

index a1d749f9fa7b9257..6e4cf5077fb885a9 100644

--- a/include/sys/socket.h

+++ b/include/sys/socket.h

@@ -98,15 +98,21 @@ extern int __sendmmsg (int __fd, struct mmsghdr *__vmessages,

 libc_hidden_proto (__sendmmsg)

 #endif

-/* Receive a message as described by MESSAGE from socket FD.

-   Returns the number of bytes read or -1 for errors.  */

 extern ssize_t __libc_recvmsg (int __fd, struct msghdr *__message,

 			       int __flags);

 extern ssize_t __recvmsg (int __fd, struct msghdr *__message,

 			  int __flags) attribute_hidden;

 #if __TIMESIZE == 64

+# define __libc_recvmsg64 __libc_recvmsg

+# define __recvmsg64  __recvmsg

 # define __recvmmsg64 __recvmmsg

 #else

+extern ssize_t __libc_recvmsg64 (int __fd, struct msghdr *__message,

+				 int __flags);

+extern ssize_t __recvmsg64 (int __fd, struct msghdr *__message,

+			    int __flags);

+/* Receive a message as described by MESSAGE from socket FD.

+   Returns the number of bytes read or -1 for errors.  */

 extern int __recvmmsg64 (int __fd, struct mmsghdr *vmessages,

 			 unsigned int vlen, int flags,

 			 struct __timespec64 *timeout);

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

index 7c75e22c6d0e9ff5..0657f4003e7116c6 100644

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

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

@@ -273,8 +273,14 @@ 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 += \

+  tst-socket-timestamp \

+  tst-socket-timestamp-compat \

+  # tests

+tests-time64 += \

+  tst-socket-timestamp-time64 \

+  tst-socket-timestamp-compat-time64

+  # tests-time64

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

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

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

index 5cd107ffa9be0699..fca9f6582db67fd7 100644

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

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

@@ -20,9 +20,9 @@

 #include <sysdep.h>

 #include <socketcall.h>

-int

-__recvmmsg64 (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,

-	      struct __timespec64 *timeout)

+static int

+recvmmsg_syscall (int fd, struct mmsghdr *vmessages, unsigned int vlen,

+		  int flags, struct __timespec64 *timeout)

 {

 #ifndef __NR_recvmmsg_time64

 # define __NR_recvmmsg_time64 __NR_recvmmsg

@@ -45,12 +45,6 @@ __recvmmsg64 (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,

       pts32 = &ts3;;

     }

-  socklen_t csize[IOV_MAX];

-  if (vlen > IOV_MAX)

-    vlen = IOV_MAX;

-  for (int i = 0; i < vlen; i++)

-    csize[i] = vmessages[i].msg_hdr.msg_controllen;

-

 # ifdef __ASSUME_RECVMMSG_SYSCALL

   r = SYSCALL_CANCEL (recvmmsg, fd, vmessages, vlen, flags, pts32);

 # else

@@ -60,11 +54,31 @@ __recvmmsg64 (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,

     {

       if (timeout != NULL)

         *timeout = valid_timespec_to_timespec64 (ts32);

+    }

+#endif

+  return r;

+}

+

+int

+__recvmmsg64 (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,

+	      struct __timespec64 *timeout)

+{

+#if __TIMESIZE != 64

+  socklen_t csize[IOV_MAX];

+  if (vlen > IOV_MAX)

+    vlen = IOV_MAX;

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

+    csize[i] = vmessages[i].msg_hdr.msg_controllen;

+#endif

+  int r = recvmmsg_syscall (fd, vmessages, vlen, flags, timeout);

+#if __TIMESIZE != 64

+  if (r > 0)

+    {

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

         __convert_scm_timestamps (&vmessages[i].msg_hdr, csize[i]);

     }

-#endif /* __ASSUME_TIME64_SYSCALLS  */

+#endif

   return r;

 }

 #if __TIMESIZE != 64

@@ -80,7 +94,7 @@ __recvmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags,

       ts64 = valid_timespec_to_timespec64 (*timeout);

       pts64 = &ts6;;

     }

-  int r = __recvmmsg64 (fd, vmessages, vlen, flags, pts64);

+  int r = recvmmsg_syscall (fd, vmessages, vlen, flags, pts64);

   if (r >= 0 && timeout != NULL)

     /* The remanining timeout will be always less the input TIMEOUT.  */

     *timeout = valid_timespec64_to_timespec (ts64);

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

index 07212f7c8641a921..c4b4704fd65d80c1 100644

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

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

@@ -20,29 +20,41 @@

 #include <sysdep-cancel.h>

 #include <socketcall.h>

+static int

+__recvmsg_syscall (int fd, struct msghdr *msg, int flags)

+{

+#ifdef __ASSUME_RECVMSG_SYSCALL

+  return SYSCALL_CANCEL (recvmsg, fd, msg, flags);

+#else

+  return SOCKETCALL_CANCEL (recvmsg, fd, msg, flags);

+#endif

+}

+

 ssize_t

-__libc_recvmsg (int fd, struct msghdr *msg, int flags)

+__libc_recvmsg64 (int fd, struct msghdr *msg, int flags)

 {

   ssize_t r;

-#ifndef __ASSUME_TIME64_SYSCALLS

+#if __TIMESIZE != 64

   socklen_t orig_controllen = msg != NULL ? msg->msg_controllen : 0;

 #endif

-#ifdef __ASSUME_RECVMSG_SYSCALL

-  r = SYSCALL_CANCEL (recvmsg, fd, msg, flags);

-#else

-  r = SOCKETCALL_CANCEL (recvmsg, fd, msg, flags);

-#endif

+  r = __recvmsg_syscall (fd, msg, flags);

-#ifndef __ASSUME_TIME64_SYSCALLS

+#if __TIMESIZE != 64

   if (r >= 0 && orig_controllen != 0)

     __convert_scm_timestamps (msg, orig_controllen);

 #endif

   return r;

 }

-weak_alias (__libc_recvmsg, recvmsg)

-weak_alias (__libc_recvmsg, __recvmsg)

 #if __TIMESIZE != 64

-weak_alias (__recvmsg, __recvmsg64)

+weak_alias (__libc_recvmsg64, __recvmsg64)

+

+ssize_t

+__libc_recvmsg (int fd, struct msghdr *msg, int flags)

+{

+  return __recvmsg_syscall (fd, msg, flags);

+}

 #endif

+weak_alias (__libc_recvmsg, recvmsg)

+weak_alias (__libc_recvmsg, __recvmsg)

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

new file mode 100644

index 0000000000000000..96a0bef0bf4a908b

--- /dev/null

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

@@ -0,0 +1 @@

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

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

new file mode 100644

index 0000000000000000..de261dae5a6385cf

--- /dev/null

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

@@ -0,0 +1,265 @@

+/* 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 <arpa/inet.h>

+#include <string.h>

+#include <support/check.h>

+#include <support/xsocket.h>

+#include <support/xunistd.h>

+#include <stdbool.h>

+

+/* 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 payload)

+{

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

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

+

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

+	   sizeof (*addr));

+

+  xclose (s);

+

+  return 0;

+}

+

+static void

+do_recvmsg_ancillary (bool use_multi_call, struct mmsghdr *mmhdr,

+		      void *msgbuf, size_t msgbuflen, int exp_payload)

+{

+  int payload;

+  struct iovec iov =

+    {

+      .iov_base = &payload,

+      .iov_len = sizeof (payload)

+    };

+  mmhdr->msg_hdr.msg_name = NULL;

+  mmhdr->msg_hdr.msg_iov = &iov;

+  mmhdr->msg_hdr.msg_iovlen = 1;

+  mmhdr->msg_hdr.msg_control = msgbuf;

+  mmhdr->msg_hdr.msg_controllen = msgbuflen;

+

+  int r;

+  if (use_multi_call)

+    {

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

+      if (r >= 0)

+	r = mmhdr->msg_len;

+    }

+  else

+    r = recvmsg (srv, &mmhdr->msg_hdr, 0);

+  TEST_COMPARE (r, sizeof (int));

+  TEST_COMPARE (payload, exp_payload);

+}

+

+/* Check if recvmsg create the additional 64 bit timestamp if only 32 bit

+   is enabled for 64 bit recvmsg symbol.  */

+static void

+do_test_large_buffer (bool mc)

+{

+  struct mmsghdr mmhdr = { 0 };

+  /* It should be large enought for either timeval/timespec and the

+     64 time type as well.  */

+

+  union

+  {

+    struct cmsghdr cmsghdr;

+    char msgbuf[512];

+  } control;

+

+  /* Enable 32 bit timeval precision and check if no 64 bit timeval stamp

+     is created.  */

+  {

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

+			sizeof (int));

+    TEST_VERIFY_EXIT (r != -1);

+

+    do_sendto (&srv_addr, 42);

+    do_recvmsg_ancillary (mc, &mmhdr, &control, sizeof control, 42);

+

+    bool found_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 (sizeof (time_t) > 4 && cmsg->cmsg_type == SO_TIMESTAMP_NEW)

+	found_timestamp = true;

+      else

+	TEST_VERIFY (cmsg->cmsg_type != SO_TIMESTAMP_NEW);

+    }

+

+    TEST_COMPARE (found_timestamp, sizeof (time_t) > 4);

+  }

+

+  /* Same as before, but for timespec.  */

+  {

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

+			sizeof (int));

+    TEST_VERIFY_EXIT (r != -1);

+

+    do_sendto (&srv_addr, 42);

+    do_recvmsg_ancillary (mc, &mmhdr, &control, sizeof control, 42);

+

+    bool found_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 (sizeof (time_t) > 4 && cmsg->cmsg_type == SO_TIMESTAMPNS_NEW)

+	found_timestamp = true;

+      else

+	TEST_VERIFY (cmsg->cmsg_type != SO_TIMESTAMPNS_NEW);

+    }

+

+    TEST_COMPARE (found_timestamp, sizeof (time_t) > 4);

+  }

+}

+

+/* Check if recvmsg does not create the additional 64 bit timestamp if

+   only 32 bit timestamp is enabled if the ancillary buffer is not large

+   enought.  Also checks if MSG_CTRUNC is set iff for 64 bit recvmsg

+   symbol.  */

+static void

+do_test_small_buffer (bool mc)

+{

+  struct mmsghdr mmhdr = { 0 };

+

+  /* Enable 32 bit timeval precision and check if no 64 bit timeval stamp

+     is created.  */

+  {

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

+			sizeof (int));

+    TEST_VERIFY_EXIT (r != -1);

+

+    union

+    {

+      struct cmsghdr cmsghdr;

+      char msgbuf[CMSG_SPACE (sizeof (struct timeval))];

+    } control;

+

+    do_sendto (&srv_addr, 42);

+    do_recvmsg_ancillary (mc, &mmhdr, &control, sizeof control, 42);

+

+    bool found_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 (sizeof (time_t) > 4 && cmsg->cmsg_type == SO_TIMESTAMP_NEW)

+	found_timestamp = true;

+      else

+	TEST_VERIFY (cmsg->cmsg_type != SO_TIMESTAMP_NEW);

+    }

+

+    if (sizeof (time_t) > 4)

+      {

+	TEST_VERIFY ((mmhdr.msg_hdr.msg_flags & MSG_CTRUNC));

+	TEST_COMPARE (found_timestamp, 0);

+      }

+    else

+      {

+	TEST_VERIFY (!(mmhdr.msg_hdr.msg_flags & MSG_CTRUNC));

+	TEST_COMPARE (found_timestamp, 0);

+      }

+  }

+

+  /* Same as before, but for timespec.  */

+  {

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

+			sizeof (int));

+    TEST_VERIFY_EXIT (r != -1);

+

+    union

+    {

+      struct cmsghdr cmsghdr;

+      char msgbuf[CMSG_SPACE (sizeof (struct timespec))];

+    } control;

+

+    do_sendto (&srv_addr, 42);

+    do_recvmsg_ancillary (mc, &mmhdr, &control, sizeof control, 42);

+

+    bool found_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 (sizeof (time_t) > 4 && cmsg->cmsg_type == SO_TIMESTAMPNS_NEW)

+	found_timestamp = true;

+      else

+	TEST_VERIFY (cmsg->cmsg_type != SO_TIMESTAMPNS_NEW);

+    }

+

+    if (sizeof (time_t) > 4)

+      {

+	TEST_VERIFY ((mmhdr.msg_hdr.msg_flags & MSG_CTRUNC));

+	TEST_COMPARE (found_timestamp, 0);

+      }

+    else

+      {

+	TEST_VERIFY ((mmhdr.msg_hdr.msg_flags & MSG_CTRUNC) == 0);

+	TEST_COMPARE (found_timestamp, 0);

+      }

+  }

+}

+

+static int

+do_test (void)

+{

+  /* This test only make sense for ABIs that support 32 bit time_t socket

+     timestampss.  */

+  if (sizeof (time_t) > 4 && __WORDSIZE == 64)

+    return 0;

+

+  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));

+  }

+

+  /* Check recvmsg;  */

+  do_test_large_buffer (false);

+  do_test_small_buffer (false);

+  /* Check recvmmsg.  */

+  do_test_large_buffer (true);

+  do_test_small_buffer (true);

+

+  return 0;

+}

+

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