nfsd: better layoutupdate bounds-checking
You could add any multiple of 2^32/PNFS_SCSI_RANGE_SIZE to nr_iomaps and
still pass this check. You'd probably still fail the following kcalloc,
but best to be paranoid since this is from-the-wire data.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/blocklayoutxdr.c b/fs/nfsd/blocklayoutxdr.c
index ca18836..6c3b316 100644
--- a/fs/nfsd/blocklayoutxdr.c
+++ b/fs/nfsd/blocklayoutxdr.c
@@ -105,18 +105,22 @@
u32 block_size)
{
struct iomap *iomaps;
- u32 nr_iomaps, expected, i;
+ u32 nr_iomaps, i;
if (len < sizeof(u32)) {
dprintk("%s: extent array too small: %u\n", __func__, len);
return -EINVAL;
}
+ len -= sizeof(u32);
+ if (len % PNFS_BLOCK_EXTENT_SIZE) {
+ dprintk("%s: extent array invalid: %u\n", __func__, len);
+ return -EINVAL;
+ }
nr_iomaps = be32_to_cpup(p++);
- expected = sizeof(__be32) + nr_iomaps * PNFS_BLOCK_EXTENT_SIZE;
- if (len != expected) {
+ if (nr_iomaps != len / PNFS_BLOCK_EXTENT_SIZE) {
dprintk("%s: extent array size mismatch: %u/%u\n",
- __func__, len, expected);
+ __func__, len, nr_iomaps);
return -EINVAL;
}