diff options
| author | Alexander Gordeev <agordeev@linux.ibm.com> | 2020-05-14 13:41:03 +1000 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2020-05-14 20:12:30 +1000 |
| commit | 3b01cce1abe2e78c4c5bb2ee39e5c3a412dae5d4 (patch) | |
| tree | 3c713bfd7ad3ca22e08316250a98cc9dcdd89a55 | |
| parent | 376b9fe72ee6e9415441e3350762c6dbd03e6cf6 (diff) | |
| download | linux-3b01cce1abe2e78c4c5bb2ee39e5c3a412dae5d4.tar.gz linux-3b01cce1abe2e78c4c5bb2ee39e5c3a412dae5d4.tar.xz | |
mm/mmap.c: add more sanity checks to get_unmapped_area()
Generic get_unmapped_area() function does sanity checks of address and
length of the area to be mapped. Yet, it lacks checking against
mmap_min_addr and mmap_end limits.
At the same time the default implementation of functions
arch_get_unmapped_area[_topdown]() and some architecture callbacks do
mmap_min_addr and mmap_end checks on their own.
Put additional checks into the generic code and do not let architecture
callbacks to get away with a possible area outside of the allowed limits.
That could also relieve arch_get_unmapped_area[_topdown]() callbacks of
own address and length sanity checks.
Link: http://lkml.kernel.org/r/d14f2cff3c891ef2c4b0337d737c6f04beacb124.1584958099.git.agordeev@linux.ibm.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
| -rw-r--r-- | mm/mmap.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 82c381fd8daa..854aefd90cd9 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2208,12 +2208,13 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); + const unsigned long mmap_end = arch_get_mmap_end(addr); unsigned long error = arch_mmap_check(addr, len, flags); if (error) return error; /* Careful about overflows.. */ - if (len > TASK_SIZE) + if (len > mmap_end - mmap_min_addr) return -ENOMEM; get_area = current->mm->get_unmapped_area; @@ -2234,7 +2235,7 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, if (IS_ERR_VALUE(addr)) return addr; - if (addr > TASK_SIZE - len) + if ((addr < mmap_min_addr) || (addr > mmap_end - len)) return -ENOMEM; if (offset_in_page(addr)) return -EINVAL; |