linux-user: Fix 'utimensat()' implementation

Implementation of syscall 'utimensat()' in 'syscall.c' uses functions
target_to_host/host_to_target_timespec() to convert values of
'struct timespec' between host and target. However, the implementation
doesn't check whether the conversion succeeds and thus can cause an
inappropriate error or succeed unappropriately instead of setting errno
EFAULT ('Bad address') which is supposed to be set in these cases.

This was confirmed with the LTP test for utimensat ('testcases/utimensat')
which fails for test cases when the errno EFAULT is expected. After changes
from this patch, the test passes for all test cases.

Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20200811113101.6636-1-Filip.Bozuta@syrmia.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index bbb61a59c72fbdf3ff45b3e2ca1ed1c277a3ada7..b4a7b605f3d4ca6d063d66914b9796e8a5d6cef7 100644 (file)
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -11919,8 +11919,13 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
             if (!arg3) {
                 tsp = NULL;
             } else {
-                target_to_host_timespec(ts, arg3);
-                target_to_host_timespec(ts+1, arg3+sizeof(struct target_timespec));
+                if (target_to_host_timespec(ts, arg3)) {
+                    return -TARGET_EFAULT;
+                }
+                if (target_to_host_timespec(ts + 1, arg3 +
+                                            sizeof(struct target_timespec))) {
+                    return -TARGET_EFAULT;
+                }
                 tsp = ts;
             }
             if (!arg2)