* [PATCH v5 2/2] linux: Fix ancillary 64-bit time timestamp conversion (BZ #28349, BZ#28350)
2022-01-24 12:28 [PATCH v5 0/2] Fix 64-bit time_t ancillary socket conversion Adhemerval Zanella
2022-01-24 12:28 ` [PATCH v5 1/2] support: Add support_socket_so_timestamp_time64 Adhemerval Zanella
@ 2022-01-24 12:28 ` Adhemerval Zanella
1 sibling, 0 replies; 3+ messages in thread
From: Adhemerval Zanella @ 2022-01-24 12:28 UTC (permalink / raw)
To: libc-alpha, Florian Weimer
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>
---
sysdeps/unix/sysv/linux/Makefile | 3 +
.../unix/sysv/linux/convert_scm_timestamps.c | 12 +-
.../sysv/linux/tst-socket-timestamp-time64.c | 1 +
.../unix/sysv/linux/tst-socket-timestamp.c | 340 ++++++++++++++++++
4 files changed, 351 insertions(+), 5 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/tst-socket-timestamp-time64.c
create mode 100644 sysdeps/unix/sysv/linux/tst-socket-timestamp.c
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 7ca9350c99..4c80ff809c 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -277,6 +277,9 @@ 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 580eb4be84..b4268a2079 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;
@@ -75,8 +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 +88,12 @@ __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 0000000000..ae424c2a70
--- /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 0000000000..548be29812
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-socket-timestamp.c
@@ -0,0 +1,340 @@
+/* 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 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: 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. */
+ 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>
--
2.32.0
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