add check for wrapping of address + size in exec()

5625ae49 · MikeCAT · Frans Kaashoek · 67a7f959 · 5625ae49
--- a/exec.c
+++ b/exec.c
@@ -44,6 +44,8 @@ exec(char *path, char **argv)
      continue;
    if(ph.memsz < ph.filesz)
      goto bad;
+    if(ph.vaddr + ph.memsz < ph.vaddr)
+      goto bad;
    if((sz = allocuvm(pgdir, sz, ph.vaddr + ph.memsz)) == 0)
      goto bad;
    if(ph.vaddr % PGSIZE != 0)