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author | Arnd Bergmann <arnd@arndb.de> | 2018-04-18 13:43:52 +0200 |
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committer | Arnd Bergmann <arnd@arndb.de> | 2018-12-18 16:13:04 +0100 |
commit | e11d4284e2f4de5048c6d1787c82226f0a198292 (patch) | |
tree | bc52de794fd0fc90e2842a9d680239d6c3e9c215 /net/socket.c | |
parent | y2038: futex: Add support for __kernel_timespec (diff) | |
download | linux-e11d4284e2f4de5048c6d1787c82226f0a198292.tar.xz linux-e11d4284e2f4de5048c6d1787c82226f0a198292.zip |
y2038: socket: Add compat_sys_recvmmsg_time64
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>
Diffstat (limited to 'net/socket.c')
-rw-r--r-- | net/socket.c | 62 |
1 files changed, 46 insertions, 16 deletions
diff --git a/net/socket.c b/net/socket.c index 593826e11a53..f137a96628f1 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 @@ out_put: 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) + return 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 <= 0) + return datagrams; + + 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, |