linux-user: Check for bad event numbers in epoll_wait
The kernel checks that the maxevents parameter to epoll_wait
is non-negative and not larger than EP_MAX_EVENTS. Add this
check to our implementation, so that:
* we fail these cases EINVAL rather than EFAULT
* we don't pass negative or overflowing values to the
lock_user() size calculation
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index c0e5cb0..5c19c5c 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -2585,6 +2585,9 @@
abi_uint events;
target_epoll_data_t data;
} TARGET_EPOLL_PACKED;
+
+#define TARGET_EP_MAX_EVENTS (INT_MAX / sizeof(struct target_epoll_event))
+
#endif
struct target_rlimit64 {
uint64_t rlim_cur;
