#include <linux/rmap.h>
#include <linux/swap.h>
#include <linux/swapops.h>
+#include <linux/security.h>
#include <asm/elf.h>
#include <asm/uaccess.h>
};
struct pagemapread {
- int pos, len;
+ int pos, len; /* units: PM_ENTRY_BYTES, not bytes */
u64 *buffer;
+ bool show_pfn;
};
#define PM_ENTRY_BYTES sizeof(u64)
return swp_type(e) | (swp_offset(e) << MAX_SWAPFILES_SHIFT);
}
-static u64 pte_to_pagemap_entry(pte_t pte)
+static u64 pte_to_pagemap_entry(struct pagemapread *pm, pte_t pte)
{
u64 pme = 0;
if (is_swap_pte(pte))
pme = PM_PFRAME(swap_pte_to_pagemap_entry(pte))
| PM_PSHIFT(PAGE_SHIFT) | PM_SWAP;
else if (pte_present(pte))
- pme = PM_PFRAME(pte_pfn(pte))
+ pme = (pm->show_pfn ? PM_PFRAME(pte_pfn(pte)) : 0)
| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT;
return pme;
}
if (vma && (vma->vm_start <= addr) &&
!is_vm_hugetlb_page(vma)) {
pte = pte_offset_map(pmd, addr);
- pfn = pte_to_pagemap_entry(*pte);
+ pfn = pte_to_pagemap_entry(pm, *pte);
/* unmap before userspace copy */
pte_unmap(pte);
}
}
#ifdef CONFIG_HUGETLB_PAGE
-static u64 huge_pte_to_pagemap_entry(pte_t pte, int offset)
+static u64 huge_pte_to_pagemap_entry(struct pagemapread *pm, pte_t pte, int offset)
{
u64 pme = 0;
if (pte_present(pte))
- pme = PM_PFRAME(pte_pfn(pte) + offset)
+ pme = (pm->show_pfn ? PM_PFRAME(pte_pfn(pte) + offset) : 0)
| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT;
return pme;
}
for (; addr != end; addr += PAGE_SIZE) {
int offset = (addr & ~hmask) >> PAGE_SHIFT;
- pfn = huge_pte_to_pagemap_entry(*pte, offset);
+ pfn = huge_pte_to_pagemap_entry(pm, *pte, offset);
err = add_to_pagemap(addr, pfn, pm);
if (err)
return err;
if (!count)
goto out_task;
- pm.len = PM_ENTRY_BYTES * (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
- pm.buffer = kmalloc(pm.len, GFP_TEMPORARY);
+ /* do not disclose physical addresses: attack vector */
+ pm.show_pfn = !security_capable(&init_user_ns, file->f_cred,
+ CAP_SYS_ADMIN);
+
+ pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
+ pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY);
ret = -ENOMEM;
if (!pm.buffer)
goto out_task;