[PATCH] linux-user: properly check flags in openat2

[Andreas Schwab <schwab@suse.de>]

target_to_host_bitmask truncates the bitmask to int.  Check that the upper
half of the flags do not have any bits set.

Signed-off-by: Andreas Schwab <schwab@suse.de>
---
 linux-user/syscall.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 8469b81878..667aea6a03 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8822,6 +8822,10 @@ static int do_openat2(CPUArchState *cpu_env, abi_long dirfd,
         }
         return ret;
     }
+    if (tswap64(how.flags) >> 32) {
+        return -TARGET_EINVAL;
+    }
+
     pathname = lock_user_string(guest_pathname);
     if (!pathname) {
         return -TARGET_EFAULT;
-- 
2.53.0


-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
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