kern: proc: Check argc after checking envblk

Fixes a crash with using this syscall

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/src/sys/os/os_proc.c b/src/sys/os/os_proc.c
index 565c663..582c077 100644
--- a/src/sys/os/os_proc.c
+++ b/src/sys/os/os_proc.c
@@ -432,13 +432,12 @@ sys_getargv(struct syscall_args *scargs)
     struct penv_blk *envblk;
     char *arg;
 
-    if (argno >= envblk->argc) {
-        return -EINVAL;
-    }
-
     if ((envblk = self->envblk) == NULL) {
         return -EIO;
     }
+    if (argno >= envblk->argc) {
+        return -EINVAL;
+    }
 
     arg = envblk->argv[argno];
     return copyoutstr(arg, u_buf, maxlen);