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UDP-RECVFROM with fork sometimes terminated - handle EINTR on recvmsg()

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This commit is contained in:
Gerhard Rieger 2022-08-13 12:04:38 +02:00
parent 9502d092a2
commit 45d87df2fd
3 changed files with 40 additions and 25 deletions
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5
CHANGES
View file

@ -4,6 +4,11 @@ Corrections:
terminating \0 Byte was written behind the last position.
Thanks to Martin Liška for sending the address sanitizer report.
UDP-RECVFROM with fork sometimes terminated when multiple packets
arrived. This issue was introduced with a bug fix in version 1.7.4.0.
Reason was not handling EAGAIN on recvmsg().
Thanks to Jamie McQuillan for reporting this issue.
Porting:
OpenSSL, at least 1.1 on Ubuntu, crashed with SIGSEGV under certain
conditions: client connection to server with certificate with empty

39
xio-socket.c
View file

@ -693,6 +693,7 @@ int xioopen_socket_datagram(int argc, const char *argv[], struct opt *opts,
#endif /* WITH_GENERICSOCKET */
/* EINTR not handled specially */
int xiogetpacketinfo(int fd)
{
#if defined(MSG_ERRQUEUE)
@ -1245,6 +1246,7 @@ void xiosigaction_hasread(int signum
return;
}
if (pid == xio_waitingfor) {
xio_waitingfor = 0; /* so this child will not set hashappened again */
xio_hashappened = true;
xio_childstatus = WEXITSTATUS(status);
Debug("xiosigaction_hasread() ->");
@ -1284,6 +1286,7 @@ void xiosigaction_hasread(int signum
PH_INIT, PH_PREBIND, PH_BIND, PH_PASTBIND, PH_EARLY, PH_PREOPEN, PH_FD,
PH_CONNECTED, PH_LATE, PH_LATE2
OPT_FORK, OPT_SO_TYPE, OPT_SO_PROTOTYPE, cloexec, OPT_RANGE, tcpwrap
EINTR is not handled specially.
*/
int _xioopen_dgram_recvfrom(struct single *xfd, int xioflags,
struct sockaddr *us, socklen_t uslen,
@ -1413,6 +1416,7 @@ int _xioopen_dgram_recvfrom(struct single *xfd, int xioflags,
socklen_t palen = sizeof(_peername); /* peer address size */
char ctrlbuff[1024]; /* ancillary messages */
struct msghdr msgh = {0};
int rc;
socket_init(pf, pa);
@ -1423,6 +1427,7 @@ int _xioopen_dgram_recvfrom(struct single *xfd, int xioflags,
drop = true;
}
Info("Recvfrom: Checking/waiting for next packet");
/* loop until select()/poll() returns valid */
do {
struct pollfd readfd;
@ -1455,15 +1460,15 @@ int _xioopen_dgram_recvfrom(struct single *xfd, int xioflags,
#if HAVE_STRUCT_MSGHDR_MSGCONTROLLEN
msgh.msg_controllen = sizeof(ctrlbuff);
#endif
if (xiogetpacketsrc(xfd->fd,
while ((rc = xiogetpacketsrc(xfd->fd,
&msgh,
MSG_PEEK
#ifdef MSG_TRUNC
|MSG_TRUNC
#endif
) < 0) {
return STAT_RETRYLATER;
}
)) < 0 &&
errno == EINTR) ;
if (rc < 0) return STAT_RETRYLATER;
palen = msgh.msg_namelen;
Notice1("receiving packet from %s"/*"src"*/,
@ -1534,24 +1539,21 @@ int _xioopen_dgram_recvfrom(struct single *xfd, int xioflags,
break;
}
/* server: continue loop with listen */
xio_waitingfor = pid;
do {
#if HAVE_PSELECT
{
{
struct timespec timeout = { LONG_MAX, 0 };
Pselect(0, NULL, NULL, NULL, &timeout, &oldset);
Sigprocmask(SIG_SETMASK, &oldset, NULL);
}
}
#else /* ! HAVE_PSELECT */
/* now we are ready to handle signals */
Sigprocmask(SIG_SETMASK, &oldset, NULL);
while (!xio_hashappened) {
Sleep(1); /* any signal speeds up return */
}
/* now we are ready to handle signals */
Sigprocmask(SIG_SETMASK, &oldset, NULL);
Sleep(1); /* any signal speeds up return */
#endif /* ! HAVE_PSELECT */
xio_waitingfor = 0; /* so this child will not set hashappened again */
} while (!xio_hashappened) ;
xio_hashappened = false;
if (xio_childstatus != 0) {
@ -1676,9 +1678,12 @@ int retropt_socket_pf(struct opt *opts, int *pf) {
}
/* this function calls recvmsg(..., MSG_PEEK, ...) to obtain information about
the arriving packet. in msgh the msg_name pointer must refer to an (empty)
sockaddr storage. */
/* This function calls recvmsg(..., MSG_PEEK, ...) to obtain information about
the arriving packet, thus it does not "consume" the packet.
In msgh the msg_name pointer must refer to an (empty) sockaddr storage.
Returns STAT_OK on success, or STAT_RETRYLATER when an error occurred,
including EINTR.
*/
int xiogetpacketsrc(int fd, struct msghdr *msgh, int flags) {
char peekbuff[1];
#if HAVE_STRUCT_IOVEC

21
xioread.c
View file

@ -119,6 +119,7 @@ ssize_t xioread(xiofile_t *file, void *buff, size_t bufsiz) {
socklen_t fromlen = sizeof(from);
char infobuff[256];
char ctrlbuff[1024]; /* ancillary messages */
int rc;
msgh.msg_name = &from;
msgh.msg_namelen = fromlen;
@ -128,14 +129,16 @@ ssize_t xioread(xiofile_t *file, void *buff, size_t bufsiz) {
#if HAVE_STRUCT_MSGHDR_MSGCONTROLLEN
msgh.msg_controllen = sizeof(ctrlbuff);
#endif
if (xiogetpacketsrc(pipe->fd, &msgh,
while ((rc = xiogetpacketsrc(pipe->fd, &msgh,
MSG_PEEK
#ifdef MSG_TRUNC
|MSG_TRUNC
#endif
) < 0) {
return -1;
}
)) < 0 &&
errno == EINTR) ;
if (rc < 0) return -1;
do {
bytes =
Recvfrom(pipe->fd, buff, bufsiz, 0, &from.soa, &fromlen);
@ -319,6 +322,7 @@ ssize_t xioread(xiofile_t *file, void *buff, size_t bufsiz) {
char infobuff[256];
struct msghdr msgh = {0};
char ctrlbuff[1024]; /* ancillary messages */
int rc;
socket_init(pipe->para.socket.la.soa.sa_family, &from);
/* get source address */
@ -330,14 +334,15 @@ ssize_t xioread(xiofile_t *file, void *buff, size_t bufsiz) {
#if HAVE_STRUCT_MSGHDR_MSGCONTROLLEN
msgh.msg_controllen = sizeof(ctrlbuff);
#endif
if (xiogetpacketsrc(pipe->fd, &msgh,
while ((rc = xiogetpacketsrc(pipe->fd, &msgh,
MSG_PEEK
#ifdef MSG_TRUNC
|MSG_TRUNC
#endif
) < 0) {
return -1;
}
)) < 0 &&
errno == EINTR) ;
if (rc < 0) return -1;
xiodopacketinfo(&msgh, true, false);
if (xiocheckpeer(pipe, &from, &pipe->para.socket.la) < 0) {
Recvfrom(pipe->fd, buff, bufsiz, 0, &from.soa, &fromlen); /* drop */