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Fix compat_sys_sigpending breakage 

The latest change of compat_sys_sigpending in commit 8f13621abc
("sigpending(): move compat to native") has broken it in two ways.

First, it tries to write 4 bytes more than userspace expects:
sizeof(old_sigset_t) == sizeof(long) == 8 instead of
sizeof(compat_old_sigset_t) == sizeof(u32) == 4.

Second, on big endian architectures these bytes are being written in the
wrong order.

This bug was found by strace test suite.

Reported-by: Anatoly Pugachev <matorola@gmail.com>
Inspired-by: Eugene Syromyatnikov <evgsyr@gmail.com>
Fixes: 8f13621abc ("sigpending(): move compat to native")
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Dmitry V. Levin 2017-08-05 23:00:50 +03:00 committed by Linus Torvalds
parent 0fdd951c9b
commit fbb77611e9
1 changed files with 7 additions and 4 deletions
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11
kernel/signal.c
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@ -3303,12 +3303,15 @@ SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32)
{
#ifdef __BIG_ENDIAN
sigset_t set;
int err = do_sigpending(&set, sizeof(old_sigset_t));
if (err == 0)
if (copy_to_user(set32, &set, sizeof(old_sigset_t)))
err = -EFAULT;
int err = do_sigpending(&set, sizeof(set.sig[0]));
if (!err)
err = put_user(set.sig[0], set32);
return err;
#else
return sys_rt_sigpending((sigset_t __user *)set32, sizeof(*set32));
#endif
}
#endif