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Diffstat (limited to 'linux-user/syscall.c')
-rw-r--r--linux-user/syscall.c22
1 files changed, 18 insertions, 4 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 29bac79b61..d6605b8b50 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -9716,8 +9716,15 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
arg4 = arg5;
arg5 = arg6;
}
- if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0)))
- return -TARGET_EFAULT;
+ if (arg2 == 0 && arg3 == 0) {
+ /* Special-case NULL buffer and zero length, which should succeed */
+ p = 0;
+ } else {
+ p = lock_user(VERIFY_WRITE, arg2, arg3, 0);
+ if (!p) {
+ return -TARGET_EFAULT;
+ }
+ }
ret = get_errno(pread64(arg1, p, arg3, target_offset64(arg4, arg5)));
unlock_user(p, arg2, ret);
return ret;
@@ -9726,8 +9733,15 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
arg4 = arg5;
arg5 = arg6;
}
- if (!(p = lock_user(VERIFY_READ, arg2, arg3, 1)))
- return -TARGET_EFAULT;
+ if (arg2 == 0 && arg3 == 0) {
+ /* Special-case NULL buffer and zero length, which should succeed */
+ p = 0;
+ } else {
+ p = lock_user(VERIFY_READ, arg2, arg3, 1);
+ if (!p) {
+ return -TARGET_EFAULT;
+ }
+ }
ret = get_errno(pwrite64(arg1, p, arg3, target_offset64(arg4, arg5)));
unlock_user(p, arg2, 0);
return ret;