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.
Signed-off-by: Arnd Bergmann arnd@arndb.de --- include/linux/compat.h | 5 ++++- include/linux/socket.h | 15 ++++++++++++++- kernel/sys_ni.c | 1 + net/compat.c | 14 +++++++------- net/socket.c | 39 +++++++++++++++++++++++++++++++++++++-- 5 files changed, 63 insertions(+), 11 deletions(-)
diff --git a/include/linux/compat.h b/include/linux/compat.h index ab0b1f48dc5b..0ede0543b84f 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -867,7 +867,10 @@ 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 compat_timespec __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..65b8db095f1d 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -2,8 +2,8 @@ #ifndef _LINUX_SOCKET_H #define _LINUX_SOCKET_H
- #include <asm/socket.h> /* arch-dependent defines */ +#include <linux/errno.h> #include <linux/sockios.h> /* the SIOCxxx I/O controls */ #include <linux/uio.h> /* iovec support */ #include <linux/types.h> /* pid_t */ @@ -349,6 +349,7 @@ extern int move_addr_to_kernel(void __user *uaddr, int ulen, struct sockaddr_sto extern int put_cmsg(struct msghdr*, int level, int type, int len, void *data);
struct timespec64; +struct compat_timespec;
/* The __sys_...msg variants allow MSG_CMSG_COMPAT iff * forbid_cmsg_compat==false @@ -359,6 +360,18 @@ 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); +#ifdef CONFIG_COMPAT_32BIT_TIME +extern int __compat_sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, + unsigned int vlen, unsigned int flags, + struct compat_timespec __user *timeout); +#else +static inline int __compat_sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, + unsigned int vlen, unsigned int flags, + struct compat_timespec __user *timeout) +{ + return -EINVAL; +} +#endif extern int __sys_sendmmsg(int fd, struct mmsghdr __user *mmsg, unsigned int vlen, unsigned int flags, bool forbid_cmsg_compat); diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index df556175be50..c3fdba58565a 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -285,6 +285,7 @@ COND_SYSCALL(perf_event_open); COND_SYSCALL(accept4); COND_SYSCALL(recvmmsg); 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 0380fbb9a321..5af2af1b9723 100644 --- a/net/compat.c +++ b/net/compat.c @@ -812,9 +812,9 @@ 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, +static int __compat_sys_recvmmsg_time64(int fd, struct compat_mmsghdr __user *mmsg, unsigned int vlen, unsigned int flags, - struct compat_timespec __user *timeout) + struct __kernel_timespec __user *timeout) { int datagrams; struct timespec64 ktspec; @@ -823,22 +823,22 @@ static int __compat_sys_recvmmsg(int fd, struct compat_mmsghdr __user *mmsg, return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen, flags | MSG_CMSG_COMPAT, NULL);
- if (compat_get_timespec64(&ktspec, timeout)) + if (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)) + if (datagrams > 0 && put_timespec64(&ktspec, timeout)) datagrams = -EFAULT;
return datagrams; }
-COMPAT_SYSCALL_DEFINE5(recvmmsg, int, fd, struct compat_mmsghdr __user *, mmsg, +COMPAT_SYSCALL_DEFINE5(recvmmsg_time64, int, fd, struct compat_mmsghdr __user *, mmsg, unsigned int, vlen, unsigned int, flags, - struct compat_timespec __user *, timeout) + struct __kernel_timespec __user *, timeout) { - return __compat_sys_recvmmsg(fd, mmsg, vlen, flags, timeout); + return __compat_sys_recvmmsg_time64(fd, mmsg, vlen, flags, timeout); }
COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args) diff --git a/net/socket.c b/net/socket.c index c0838a278cfd..f4b6be81c6af 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2473,6 +2473,37 @@ SYSCALL_DEFINE5(recvmmsg, int, fd, struct mmsghdr __user *, mmsg, return do_sys_recvmmsg(fd, mmsg, vlen, flags, timeout); }
+#ifdef CONFIG_COMPAT_32BIT_TIME +int __compat_sys_recvmmsg(int fd, struct mmsghdr __user *mmsg, + unsigned int vlen, unsigned int flags, + struct compat_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; +} + +COMPAT_SYSCALL_DEFINE5(recvmmsg, int, fd, struct mmsghdr __user *, mmsg, + unsigned int, vlen, unsigned int, flags, + struct compat_timespec __user *, timeout) +{ + return __compat_sys_recvmmsg(fd, mmsg, vlen, flags, timeout); +} +#endif + #ifdef __ARCH_WANT_SYS_SOCKETCALL /* Argument list sizes for sys_socketcall */ #define AL(x) ((x) * sizeof(unsigned long)) @@ -2590,8 +2621,12 @@ 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 = do_sys_recvmmsg(a0, (struct mmsghdr __user *)a1, a[2], + a[3], (struct __kernel_timespec __user *)a[4]); + else + err = __compat_sys_recvmmsg(a0, (struct mmsghdr __user *)a1, a[2], + a[3], (struct compat_timespec __user *)a[4]); break; case SYS_ACCEPT4: err = __sys_accept4(a0, (struct sockaddr __user *)a1,