Commit 2ba7fae3 authored by Peter Maydell's avatar Peter Maydell Committed by Riku Voipio
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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: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarRiku Voipio <riku.voipio@linaro.org>
parent 700fa58e

linux-user/syscall.c

+5 −0
Original line number Diff line number Diff line
@@ -11501,6 +11501,11 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
        int maxevents = arg3;

        int timeout = arg4;



        if (maxevents <= 0 || maxevents > TARGET_EP_MAX_EVENTS) {

            ret = -TARGET_EINVAL;

            break;

        }



        target_ep = lock_user(VERIFY_WRITE, arg2,

                              maxevents * sizeof(struct target_epoll_event), 1);

        if (!target_ep) {

linux-user/syscall_defs.h

+3 −0
Original line number Diff line number Diff line
@@ -2585,6 +2585,9 @@ struct target_epoll_event { 
    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;