Add ELF header sanity check

aswaterman · aswaterman · commit 1f326d6ed85e · 2024-04-17T14:56:20.000-07:00
diff --git a/pk/elf.c b/pk/elf.c
@@ -76,6 +76,8 @@ void load_elf(const char* fn, elf_info* info)
       panic("not a statically linked ELF program");
     }
     if(ph[i].p_type == PT_LOAD && ph[i].p_memsz) {
+      if (ph[i].p_filesz > ph[i].p_memsz)
+        goto fail;
       uintptr_t prepad = ph[i].p_vaddr % RISCV_PGSIZE;
       uintptr_t vaddr = ph[i].p_vaddr + bias;
       if (vaddr + ph[i].p_memsz > info->brk_min)

Original file line number	Diff line number	Diff line change
`@@ -76,6 +76,8 @@ void load_elf(const char* fn, elf_info* info)`
`76`	`76`	`panic("not a statically linked ELF program");`
`77`	`77`	`}`
`78`	`78`	`if(ph[i].p_type == PT_LOAD && ph[i].p_memsz) {`
	`79`	`+ if (ph[i].p_filesz > ph[i].p_memsz)`
	`80`	`+ goto fail;`
`79`	`81`	`uintptr_t prepad = ph[i].p_vaddr % RISCV_PGSIZE;`
`80`	`82`	`uintptr_t vaddr = ph[i].p_vaddr + bias;`
`81`	`83`	`if (vaddr + ph[i].p_memsz > info->brk_min)`