The patch titled
Subject: pagemap: hide physical addresses from non-privileged users
has been added to the -mm tree. Its filename is
pagemap-hide-physical-addresses-from-non-privileged-users.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/pagemap-hide-physical-addresses-from-non-privileged-users.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/pagemap-hide-physical-addresses-from-non-privileged-users.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
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------------------------------------------------------
From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Subject: pagemap: hide physical addresses from non-privileged users
This patch makes pagemap readable for normal users and hides physical
addresses from them. For some use-cases PFN isn't required at all.
See http://lkml.kernel.org/r/1425935472-17949-1-git-send-email-kirill@xxxxxxxxxxxxx
Fixes: ab676b7d6fbf ("pagemap: do not leak physical addresses to non-privileged userspace")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Mark Williamson <mwilliamson@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff -puN fs/proc/task_mmu.c~pagemap-hide-physical-addresses-from-non-privileged-users fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~pagemap-hide-physical-addresses-from-non-privileged-users
+++ a/fs/proc/task_mmu.c
@@ -940,6 +940,7 @@ typedef struct {
struct pagemapread {
int pos, len; /* units: PM_ENTRY_BYTES, not bytes */
pagemap_entry_t *buffer;
+ bool show_pfn;
};
#define PAGEMAP_WALK_SIZE (PMD_SIZE)
@@ -1016,7 +1017,8 @@ static pagemap_entry_t pte_to_pagemap_en
struct page *page = NULL;
if (pte_present(pte)) {
- frame = pte_pfn(pte);
+ if (pm->show_pfn)
+ frame = pte_pfn(pte);
flags |= PM_PRESENT;
page = vm_normal_page(vma, addr, pte);
if (pte_soft_dirty(pte))
@@ -1066,8 +1068,9 @@ static int pagemap_pmd_range(pmd_t *pmdp
*/
if (pmd_present(pmd)) {
flags |= PM_PRESENT;
- frame = pmd_pfn(pmd) +
- ((addr & ~PMD_MASK) >> PAGE_SHIFT);
+ if (pm->show_pfn)
+ frame = pmd_pfn(pmd) +
+ ((addr & ~PMD_MASK) >> PAGE_SHIFT);
}
for (; addr != end; addr += PAGE_SIZE) {
@@ -1076,7 +1079,7 @@ static int pagemap_pmd_range(pmd_t *pmdp
err = add_to_pagemap(addr, &pme, pm);
if (err)
break;
- if (flags & PM_PRESENT)
+ if (pm->show_pfn && (flags & PM_PRESENT))
frame++;
}
spin_unlock(ptl);
@@ -1130,8 +1133,9 @@ static int pagemap_hugetlb_range(pte_t *
flags |= PM_FILE;
flags |= PM_PRESENT;
- frame = pte_pfn(pte) +
- ((addr & ~hmask) >> PAGE_SHIFT);
+ if (pm->show_pfn)
+ frame = pte_pfn(pte) +
+ ((addr & ~hmask) >> PAGE_SHIFT);
}
for (; addr != end; addr += PAGE_SIZE) {
@@ -1140,7 +1144,7 @@ static int pagemap_hugetlb_range(pte_t *
err = add_to_pagemap(addr, &pme, pm);
if (err)
return err;
- if (flags & PM_PRESENT)
+ if (pm->show_pfn && (flags & PM_PRESENT))
frame++;
}
@@ -1199,6 +1203,9 @@ static ssize_t pagemap_read(struct file
if (!count)
goto out_mm;
+ /* do not disclose physical addresses: attack vector */
+ pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN);
+
pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY);
ret = -ENOMEM;
@@ -1268,10 +1275,6 @@ static int pagemap_open(struct inode *in
{
struct mm_struct *mm;
- /* do not disclose physical addresses: attack vector */
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
mm = proc_mem_open(inode, PTRACE_MODE_READ);
if (IS_ERR(mm))
return PTR_ERR(mm);
_
Patches currently in -mm which might be from khlebnikov@xxxxxxxxxxxxxx are
pagemap-check-permissions-and-capabilities-at-open-time.patch
pagemap-switch-to-the-new-format-and-do-some-cleanup.patch
pagemap-rework-hugetlb-and-thp-report.patch
pagemap-hide-physical-addresses-from-non-privileged-users.patch
pagemap-add-mmap-exclusive-bit-for-marking-pages-mapped-only-here.patch
pagemap-add-mmap-exclusive-bit-for-marking-pages-mapped-only-here-fix.patch
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