diff options
| -rw-r--r-- | linux-user/syscall.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index fccf9f0a26..7c108abcf2 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -6636,11 +6636,22 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, p2 = lock_user(VERIFY_WRITE, arg2, arg3, 0); if (!p || !p2) { ret = -TARGET_EFAULT; + } else if (!arg3) { + /* Short circuit this for the magic exe check. */ + ret = -TARGET_EINVAL; } else if (is_proc_myself((const char *)p, "exe")) { char real[PATH_MAX], *temp; temp = realpath(exec_path, real); - ret = temp == NULL ? get_errno(-1) : strlen(real) ; - snprintf((char *)p2, arg3, "%s", real); + /* Return value is # of bytes that we wrote to the buffer. */ + if (temp == NULL) { + ret = get_errno(-1); + } else { + /* Don't worry about sign mismatch as earlier mapping + * logic would have thrown a bad address error. */ + ret = MIN(strlen(real), arg3); + /* We cannot NUL terminate the string. */ + memcpy(p2, real, ret); + } } else { ret = get_errno(readlink(path(p), p2, arg3)); } |