The patch titled
Subject: proc/kcore: don't bounds check against address 0
has been removed from the -mm tree. Its filename was
proc-kcore-dont-bounds-check-against-address-0.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Laura Abbott <labbott@xxxxxxxxxx>
Subject: proc/kcore: don't bounds check against address 0
The existing kcore code checks for bad addresses against __va(0) with the
assumption that this is the lowest address on the system. This may not
hold true on some systems (e.g. arm64) and produce overflows and crashes.
Switch to using other functions to validate the address range.
It's currently only seen on arm64 and it's not clear if anyone wants to
use that particular combination on a stable release. So this is not
urgent for stable.
Link: http://lkml.kernel.org/r/20180501201143.15121-1-labbott@xxxxxxxxxx
Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
Tested-by: Dave Anderson <anderson@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>a
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/kcore.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)
diff -puN fs/proc/kcore.c~proc-kcore-dont-bounds-check-against-address-0 fs/proc/kcore.c
--- a/fs/proc/kcore.c~proc-kcore-dont-bounds-check-against-address-0
+++ a/fs/proc/kcore.c
@@ -209,25 +209,34 @@ kclist_add_private(unsigned long pfn, un
{
struct list_head *head = (struct list_head *)arg;
struct kcore_list *ent;
+ struct page *p;
+
+ if (!pfn_valid(pfn))
+ return 1;
+
+ p = pfn_to_page(pfn);
+ if (!memmap_valid_within(pfn, p, page_zone(p)))
+ return 1;
ent = kmalloc(sizeof(*ent), GFP_KERNEL);
if (!ent)
return -ENOMEM;
- ent->addr = (unsigned long)__va((pfn << PAGE_SHIFT));
+ ent->addr = (unsigned long)page_to_virt(p);
ent->size = nr_pages << PAGE_SHIFT;
- /* Sanity check: Can happen in 32bit arch...maybe */
- if (ent->addr < (unsigned long) __va(0))
+ if (!virt_addr_valid(ent->addr))
goto free_out;
/* cut not-mapped area. ....from ppc-32 code. */
if (ULONG_MAX - ent->addr < ent->size)
ent->size = ULONG_MAX - ent->addr;
- /* cut when vmalloc() area is higher than direct-map area */
- if (VMALLOC_START > (unsigned long)__va(0)) {
- if (ent->addr > VMALLOC_START)
- goto free_out;
+ /*
+ * We've already checked virt_addr_valid so we know this address
+ * is a valid pointer, therefore we can check against it to determine
+ * if we need to trim
+ */
+ if (VMALLOC_START > ent->addr) {
if (VMALLOC_START - ent->addr < ent->size)
ent->size = VMALLOC_START - ent->addr;
}
_
Patches currently in -mm which might be from labbott@xxxxxxxxxx are
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