The patch titled
Subject: mm/mmap.c: do not allow mappings outside of allowed limits
has been added to the -mm tree. Its filename is
mm-mmapc-do-not-allow-mappings-outside-of-allowed-limits.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-mmapc-do-not-allow-mappings-outside-of-allowed-limits.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-mmapc-do-not-allow-mappings-outside-of-allowed-limits.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Subject: mm/mmap.c: do not allow mappings outside of allowed limits
It is possible to request a fixed mapping address below mmap_min_addr and
succeed. This update adds early checks of mmap_min_addr and mmap_end
boundaries and fixes the above issue.
Link: http://lkml.kernel.org/r/d6da1319114a331095052638f0ffa3ccb0be58f1.1584958099.git.agordeev@xxxxxxxxxxxxx
Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
--- a/mm/mmap.c~mm-mmapc-do-not-allow-mappings-outside-of-allowed-limits
+++ a/mm/mmap.c
@@ -62,6 +62,14 @@
#define arch_mmap_check(addr, len, flags) (0)
#endif
+#ifndef arch_get_mmap_end
+#define arch_get_mmap_end(addr) (TASK_SIZE)
+#endif
+
+#ifndef arch_get_mmap_base
+#define arch_get_mmap_base(addr, base) (base)
+#endif
+
#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN;
const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX;
@@ -1369,6 +1377,7 @@ unsigned long do_mmap(struct file *file,
unsigned long pgoff, unsigned long *populate,
struct list_head *uf)
{
+ const unsigned long mmap_end = arch_get_mmap_end(addr);
struct mm_struct *mm = current->mm;
int pkey = 0;
@@ -1391,8 +1400,12 @@ unsigned long do_mmap(struct file *file,
if (flags & MAP_FIXED_NOREPLACE)
flags |= MAP_FIXED;
- if (!(flags & MAP_FIXED))
+ if (flags & MAP_FIXED) {
+ if ((addr < mmap_min_addr) || (addr > mmap_end))
+ return -ENOMEM;
+ } else {
addr = round_hint_to_min(addr);
+ }
/* Careful about overflows.. */
len = PAGE_ALIGN(len);
@@ -2089,14 +2102,6 @@ unsigned long vm_unmapped_area(struct vm
return addr;
}
-#ifndef arch_get_mmap_end
-#define arch_get_mmap_end(addr) (TASK_SIZE)
-#endif
-
-#ifndef arch_get_mmap_base
-#define arch_get_mmap_base(addr, base) (base)
-#endif
-
/* Get an address range which is currently unmapped.
* For shmat() with addr=0.
*
_
Patches currently in -mm which might be from agordeev@xxxxxxxxxxxxx are
mm-mmapc-add-more-sanity-checks-to-get_unmapped_area.patch
mm-mmapc-do-not-allow-mappings-outside-of-allowed-limits.patch
