From 948ce73b31fdb0860bcec4b8e62b14e88234f98a Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Thu, 27 Jan 2022 16:45:18 -0300 Subject: 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 --- sysdeps/unix/sysv/linux/recvmsg.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) (limited to 'sysdeps/unix/sysv/linux/recvmsg.c') diff --git a/sysdeps/unix/sysv/linux/recvmsg.c b/sysdeps/unix/sysv/linux/recvmsg.c index 53e567ed31..401d415b2c 100644 --- a/sysdeps/unix/sysv/linux/recvmsg.c +++ b/sysdeps/unix/sysv/linux/recvmsg.c @@ -20,29 +20,41 @@ #include #include +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) -- cgit v1.2.3-70-g09d2