add overflow check for vaddr

src/elf.rs

@@ -12,6 +12,7 @@ pub enum Error {
     BadMagic,
     BadType,
     BadMachine,
+    BadAddr,
 }
 
 struct Phdr {
@@ -101,7 +102,8 @@ pub fn load(elf: Vec<u8>, mem: &mut [u8]) -> Result<u32, Error> {
             continue;
         }
 
-        let vaddr = (phdr.vaddr - RAM_BASE) as usize;
+        if let Some(vaddr) = phdr.vaddr.checked_sub(RAM_BASE) {
+            let vaddr = vaddr as usize;
             let memsz = phdr.memsz as usize;
 
             let pos = rdr.position();
@@ -110,6 +112,9 @@ pub fn load(elf: Vec<u8>, mem: &mut [u8]) -> Result<u32, Error> {
                 return Err(Error::Eof);
             }
             rdr.set_position(pos);
+        } else {
+            return Err(Error::BadAddr);
+        }
     }
 
     Ok(entry)

src/lib.rs

@@ -336,6 +336,7 @@ pub fn run(path: String) -> Result<()> {
             elf::Error::BadMagic => bail!("bad magic"),
             elf::Error::BadType => bail!("invalid executable"),
             elf::Error::BadMachine => bail!("foreign elf architecture"),
+            elf::Error::BadAddr => bail!("bad virt address offset"),
         },
     };