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

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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 check 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>
This commit is contained in:
Adhemerval Zanella 2021-09-27 16:07:08 -03:00
parent a4cf12360f
commit 21e0f45c7d
4 changed files with 354 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
sysdeps/unix/sysv/linux/Makefile
View File

@ -275,6 +275,9 @@ 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 \

11
sysdeps/unix/sysv/linux/convert_scm_timestamps.c
View File

@ -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;
@ -75,8 +77,6 @@ __convert_scm_timestamps (struct msghdr *msg, socklen_t msgsize)
tvts[1] = tmp[1];
break;
}
last = cmsg;
}
if (last == NULL || type == 0)
@ -88,10 +88,11 @@ __convert_scm_timestamps (struct msghdr *msg, socklen_t msgsize)
return;
}
/* Zero memory for the new cmsghdr, required by CMSG_NXTHDR. */
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);

1
sysdeps/unix/sysv/linux/tst-socket-timestamp-time64.c Normal file
View File

@ -0,0 +1 @@
#include "tst-socket-timestamp.c"

344
sysdeps/unix/sysv/linux/tst-socket-timestamp.c Normal file
View File

@ -0,0 +1,344 @@
/* Check recvmsg/recvmmsg 64-bit timestamp support.
Copyright (C) 2021 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 send and 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));
return 0;
}
static void
do_recvmsg_slack_ancillary (bool use_multi_call, int s, void *cmsg,
size_t slack, size_t tsize, int exp_msg)
{
int msg;
struct iovec iov =
{
.iov_base = &msg,
.iov_len = sizeof (msg)
};
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 (msg, exp_msg);
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;
}
}
/* If there is not timestamp in the ancilliary data, recvmsg should set
the flag inidcating it. */
if (exp_timestamp && !timestamp)
TEST_VERIFY (mmhdr.msg_hdr.msg_flags & MSG_TRUNC);
else
TEST_COMPARE (timestamp, exp_timestamp);
}
/* Check if the extra ancillary space is correctly handled by recvmsg and
recvmmsg: if there is no extra space for the 64-bit timestamp the syscall
should set MSG_TRUNC flag, otherwise an extra cmsghdr with the converted
timestamp is appended at the message control 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;
}
}
/* If there is no timestamp in the ancillary data, recvmsg should set
the flag to indicate it. */
if (!timestamp)
TEST_VERIFY (mmhdr.msg_hdr.msg_flags & MSG_TRUNC);
else
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>