commit e098446037da532d4a250efac9a813bc22f3669f Author: Adhemerval Zanella 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 Reviewed-by: Florian Weimer (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 + . */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* 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