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| author | Mike Kravetz <mike.kravetz@oracle.com> | 2018-03-23 02:17:13 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-06-01 02:30:03 +0300 |
| commit | 131802b8292d35e8a407469c485565b199ed79cf (patch) | |
| tree | 4c1a5124ef047f2b5b7125f563c84b7722980230 /mm | |
| parent | 4cba2554682469496ff48536d50c399110d20043 (diff) | |
| download | linux-131802b8292d35e8a407469c485565b199ed79cf.tar.xz | |
hugetlbfs: check for pgoff value overflow
commit 63489f8e821144000e0bdca7e65a8d1cc23a7ee7 upstream.
A vma with vm_pgoff large enough to overflow a loff_t type when
converted to a byte offset can be passed via the remap_file_pages system
call. The hugetlbfs mmap routine uses the byte offset to calculate
reservations and file size.
A sequence such as:
mmap(0x20a00000, 0x600000, 0, 0x66033, -1, 0);
remap_file_pages(0x20a00000, 0x600000, 0, 0x20000000000000, 0);
will result in the following when task exits/file closed,
kernel BUG at mm/hugetlb.c:749!
Call Trace:
hugetlbfs_evict_inode+0x2f/0x40
evict+0xcb/0x190
__dentry_kill+0xcb/0x150
__fput+0x164/0x1e0
task_work_run+0x84/0xa0
exit_to_usermode_loop+0x7d/0x80
do_syscall_64+0x18b/0x190
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
The overflowed pgoff value causes hugetlbfs to try to set up a mapping
with a negative range (end < start) that leaves invalid state which
causes the BUG.
The previous overflow fix to this code was incomplete and did not take
the remap_file_pages system call into account.
[mike.kravetz@oracle.com: v3]
Link: http://lkml.kernel.org/r/20180309002726.7248-1-mike.kravetz@oracle.com
[akpm@linux-foundation.org: include mmdebug.h]
[akpm@linux-foundation.org: fix -ve left shift count on sh]
Link: http://lkml.kernel.org/r/20180308210502.15952-1-mike.kravetz@oracle.com
Fixes: 045c7a3f53d9 ("hugetlbfs: fix offset overflow in hugetlbfs mmap")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Nic Losby <blurbdust@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
- Use a conditional WARN() instead of VM_WARN()
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/hugetlb.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 390f0ac4eed6..a489d9338ac4 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -18,6 +18,7 @@ #include <linux/bootmem.h> #include <linux/sysfs.h> #include <linux/slab.h> +#include <linux/mmdebug.h> #include <linux/rmap.h> #include <linux/swap.h> #include <linux/swapops.h> @@ -3097,6 +3098,14 @@ int hugetlb_reserve_pages(struct inode *inode, struct hstate *h = hstate_inode(inode); struct hugepage_subpool *spool = subpool_inode(inode); + /* This should never happen */ + if (from > to) { +#ifdef CONFIG_DEBUG_VM + WARN(1, "%s called with a negative range\n", __func__); +#endif + return -EINVAL; + } + /* * Only apply hugepage reservation if asked. At fault time, an * attempt will be made for VM_NORESERVE to allocate a page |