recvmmsg() takes two arguments to pointers of structures that differ between 32-bit and 64-bit architectures: mmsghdr and timespec.
For y2038 compatbility, we are changing the native system call from timespec to __kernel_timespec with a 64-bit time_t (in another patch), and use the existing compat system call on both 32-bit and 64-bit architectures for compatibility with traditional 32-bit user space.
As we now have two variants of recvmmsg() for 32-bit tasks that are both different from the variant that we use on 64-bit tasks, this means we also require two compat system calls!
The solution I picked is to flip things around: The existing compat_sys_recvmmsg() call gets moved from net/compat.c into net/socket.c and now handles the case for old user space on all architectures that have set CONFIG_COMPAT_32BIT_TIME. A new compat_sys_recvmmsg_time64() call gets added in the old place for 64-bit architectures only, this one handles the case of a compat mmsghdr structure combined with __kernel_timespec.
In the indirect sys_socketcall(), we now need to call either do_sys_recvmmsg() or __compat_sys_recvmmsg(), depending on what kind of architecture we are on. For compat_sys_socketcall(), no such change is needed, we always call __compat_sys_recvmmsg().
I decided to not add a new SYS_RECVMMSG_TIME64 socketcall: Any libc implementation for 64-bit time_t will need significant changes including an updated asm/unistd.h, and it seems better to consistently use the separate syscalls that configuration, leaving the socketcall only for backward compatibility with 32-bit time_t based libc.
The naming is asymmetric for the moment, so both existing syscalls entry points keep their names, while the new ones are recvmmsg_time32 and compat_recvmmsg_time64 respectively. I expect that we will rename the compat syscalls later as we start using generated syscall tables everywhere and add these entry points.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- include/linux/compat.h | 5 +++- include/linux/socket.h | 9 ++++-- include/linux/syscalls.h | 3 ++ kernel/sys_ni.c | 2 ++ net/compat.c | 34 ++++++++-------------- net/socket.c | 62 +++++++++++++++++++++++++++++----------- 6 files changed, 73 insertions(+), 42 deletions(-)
diff --git a/include/linux/compat.h b/include/linux/compat.h index 8be8daa38c9a..72969d303434 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -893,7 +893,10 @@ asmlinkage long compat_sys_move_pages(pid_t pid, compat_ulong_t nr_pages, asmlinkage long compat_sys_rt_tgsigqueueinfo(compat_pid_t tgid, compat_pid_t pid, int sig, struct compat_siginfo __user *uinfo); -asmlinkage long compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg, +asmlinkage long compat_sys_recvmmsg_time64(int fd, struct compat_mmsghdr __user *mmsg, + unsigned vlen, unsigned int flags, + struct __kernel_timespec __user *timeout); +asmlinkage long compat_sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned vlen, unsigned int flags, struct old_timespec32 __user *timeout); asmlinkage long compat_sys_wait4(compat_pid_t pid, diff --git a/include/linux/socket.h b/include/linux/socket.h index 8b571e9b9f76..333b5df8a1b2 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -348,7 +348,8 @@ struct ucred { extern int move_addr_to_kernel(void __user *uaddr, int ulen, struct sockaddr_storage *kaddr); extern int put_cmsg(struct msghdr*, int level, int type, int len, void *data);
-struct timespec64; +struct __kernel_timespec; +struct old_timespec32;
/* The __sys_...msg variants allow MSG_CMSG_COMPAT iff * forbid_cmsg_compat==false @@ -357,8 +358,10 @@ extern long __sys_recvmsg(int fd, struct user_msghdr __user *msg, unsigned int flags, bool forbid_cmsg_compat); extern long __sys_sendmsg(int fd, struct user_msghdr __user *msg, unsigned int flags, bool forbid_cmsg_compat); -extern int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, - unsigned int flags, struct timespec64 *timeout); +extern int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, + unsigned int vlen, unsigned int flags, + struct __kernel_timespec __user *timeout, + struct old_timespec32 __user *timeout32); extern int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, unsigned int flags, bool forbid_cmsg_compat); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 247ad9eca955..03cda6793be3 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -843,6 +843,9 @@ asmlinkage long sys_accept4(int, struct sockaddr __user *, int __user *, int); asmlinkage long sys_recvmmsg(int fd, struct mmsghdr __user *msg, unsigned int vlen, unsigned flags, struct __kernel_timespec __user *timeout); +asmlinkage long sys_recvmmsg_time32(int fd, struct mmsghdr __user *msg, + unsigned int vlen, unsigned flags, + struct old_timespec32 __user *timeout);
asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr, int options, struct rusage __user *ru); diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index df556175be50..ab9d0e3c6d50 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -284,7 +284,9 @@ COND_SYSCALL_COMPAT(move_pages); COND_SYSCALL(perf_event_open); COND_SYSCALL(accept4); COND_SYSCALL(recvmmsg); +COND_SYSCALL(recvmmsg_time32); COND_SYSCALL_COMPAT(recvmmsg); +COND_SYSCALL_COMPAT(recvmmsg_time64);
/* * Architecture specific syscalls: see further below diff --git a/net/compat.c b/net/compat.c index 47a614b370cd..f7084780a8f8 100644 --- a/net/compat.c +++ b/net/compat.c @@ -810,34 +810,23 @@ COMPAT_SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, buf, compat_size_t, len return __compat_sys_recvfrom(fd, buf, len, flags, addr, addrlen); }
-static int __compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg, - unsigned int vlen, unsigned int flags, - struct old_timespec32 __user *timeout) +COMPAT_SYSCALL_DEFINE5(recvmmsg_time64, int, fd, struct compat_mmsghdr __user *, mmsg, + unsigned int, vlen, unsigned int, flags, + struct __kernel_timespec __user *, timeout) { - int datagrams; - struct timespec64 ktspec; - - if (timeout == NULL) - return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen, - flags | MSG_CMSG_COMPAT, NULL); - - if (compat_get_timespec64(&ktspec, timeout)) - return -EFAULT; - - datagrams = __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen, - flags | MSG_CMSG_COMPAT, &ktspec); - if (datagrams > 0 && compat_put_timespec64(&ktspec, timeout)) - datagrams = -EFAULT; - - return datagrams; + return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen, + flags | MSG_CMSG_COMPAT, timeout, NULL); }
+#ifdef CONFIG_COMPAT_32BIT_TIME COMPAT_SYSCALL_DEFINE5(recvmmsg, int, fd, struct compat_mmsghdr __user *, mmsg, unsigned int, vlen, unsigned int, flags, struct old_timespec32 __user *, timeout) { - return __compat_sys_recvmmsg(fd, mmsg, vlen, flags, timeout); + return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen, + flags | MSG_CMSG_COMPAT, NULL, timeout); } +#endif
COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args) { @@ -925,8 +914,9 @@ COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args) ret = __compat_sys_recvmsg(a0, compat_ptr(a1), a[2]); break; case SYS_RECVMMSG: - ret = __compat_sys_recvmmsg(a0, compat_ptr(a1), a[2], a[3], - compat_ptr(a[4])); + ret = __sys_recvmmsg(a0, compat_ptr(a1), a[2], + a[3] | MSG_CMSG_COMPAT, NULL, + compat_ptr(a[4])); break; case SYS_ACCEPT4: ret = __sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), a[3]); diff --git a/net/socket.c b/net/socket.c index 593826e11a53..f6a2d3a7b611 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2341,8 +2341,9 @@ SYSCALL_DEFINE3(recvmsg, int, fd, struct user_msghdr __user *, msg, * Linux recvmmsg interface */
-int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, - unsigned int flags, struct timespec64 *timeout) +static int do_recvmmsg(int fd, struct mmsghdr __user *mmsg, + unsigned int vlen, unsigned int flags, + struct timespec64 *timeout) { int fput_needed, err, datagrams; struct socket *sock; @@ -2451,25 +2452,32 @@ int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, return datagrams; }
-static int do_sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, - unsigned int vlen, unsigned int flags, - struct __kernel_timespec __user *timeout) +int __sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, + unsigned int vlen, unsigned int flags, + struct __kernel_timespec __user *timeout, + struct old_timespec32 __user *timeout32) { int datagrams; struct timespec64 timeout_sys;
- if (flags & MSG_CMSG_COMPAT) - return -EINVAL; - - if (!timeout) - return __sys_recvmmsg(fd, mmsg, vlen, flags, NULL); + if (timeout && get_timespec64(&timeout_sys, timeout)) + return -EFAULT;
- if (get_timespec64(&timeout_sys, timeout)) + if (timeout32 && get_old_timespec32(&timeout_sys, timeout32)) return -EFAULT;
- datagrams = __sys_recvmmsg(fd, mmsg, vlen, flags, &timeout_sys); + if (!timeout && !timeout32) + do_recvmmsg(fd, mmsg, vlen, flags, NULL); + + datagrams = do_recvmmsg(fd, mmsg, vlen, flags, &timeout_sys);
- if (datagrams > 0 && put_timespec64(&timeout_sys, timeout)) + if (!datagrams) + return 0; + + if (timeout && put_timespec64(&timeout_sys, timeout)) + datagrams = -EFAULT; + + if (timeout32 && put_old_timespec32(&timeout_sys, timeout32)) datagrams = -EFAULT;
return datagrams; @@ -2479,8 +2487,23 @@ SYSCALL_DEFINE5(recvmmsg, int, fd, struct mmsghdr __user *, mmsg, unsigned int, vlen, unsigned int, flags, struct __kernel_timespec __user *, timeout) { - return do_sys_recvmmsg(fd, mmsg, vlen, flags, timeout); + if (flags & MSG_CMSG_COMPAT) + return -EINVAL; + + return __sys_recvmmsg(fd, mmsg, vlen, flags, timeout, NULL); +} + +#ifdef CONFIG_COMPAT_32BIT_TIME +SYSCALL_DEFINE5(recvmmsg_time32, int, fd, struct mmsghdr __user *, mmsg, + unsigned int, vlen, unsigned int, flags, + struct old_timespec32 __user *, timeout) +{ + if (flags & MSG_CMSG_COMPAT) + return -EINVAL; + + return __sys_recvmmsg(fd, mmsg, vlen, flags, NULL, timeout); } +#endif
#ifdef __ARCH_WANT_SYS_SOCKETCALL /* Argument list sizes for sys_socketcall */ @@ -2600,8 +2623,15 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args) a[2], true); break; case SYS_RECVMMSG: - err = do_sys_recvmmsg(a0, (struct mmsghdr __user *)a1, a[2], - a[3], (struct __kernel_timespec __user *)a[4]); + if (IS_ENABLED(CONFIG_64BIT) || !IS_ENABLED(CONFIG_64BIT_TIME)) + err = __sys_recvmmsg(a0, (struct mmsghdr __user *)a1, + a[2], a[3], + (struct __kernel_timespec __user *)a[4], + NULL); + else + err = __sys_recvmmsg(a0, (struct mmsghdr __user *)a1, + a[2], a[3], NULL, + (struct old_timespec32 __user *)a[4]); break; case SYS_ACCEPT4: err = __sys_accept4(a0, (struct sockaddr __user *)a1,