diff options
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/kern/kern_loader.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/sys/kern/kern_loader.c b/sys/kern/kern_loader.c index 73dc8c7..53ba8c2 100644 --- a/sys/kern/kern_loader.c +++ b/sys/kern/kern_loader.c @@ -58,10 +58,10 @@ int loader_load(struct vas vas, const void *dataptr, struct auxval *auxv, { const Elf64_Ehdr *hdr = dataptr; Elf64_Phdr *phdr; - vm_prot_t prot = 0; + vm_prot_t prot = PROT_USER; uintptr_t physmem; - uintptr_t map_addr; + uintptr_t max_addr, map_addr; size_t misalign, page_count; int status; @@ -93,6 +93,24 @@ int loader_load(struct vas vas, const void *dataptr, struct auxval *auxv, misalign = phdr->p_vaddr & (GRANULE - 1); page_count = __DIV_ROUNDUP(phdr->p_memsz + misalign, GRANULE); + max_addr = phdr->p_vaddr + (GRANULE * page_count); + + /* + * We are assuming this is a user program that we are loading. + * All user programs should be on the lower half of the address + * space. We will check that before we begin doing anything here. + * + * We are also going to check if the virtual address the program + * header refers to overflows into the higher half. If anything + * goes into the higher half, we won't simply drop the phdr, + * we'll instead assume caller error and return -EINVAL. + */ + if (phdr->p_vaddr >= VM_HIGHER_HALF) { + return -EINVAL; + } else if (max_addr >= VM_HIGHER_HALF) { + /* Overflows into higher half */ + return -EINVAL; + } physmem = vm_alloc_pageframe(page_count); |