From 4b15da44e742871206582f6aa2997b009648f02f Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Fri, 18 Mar 2016 11:31:17 -0400 Subject: [PATCH] 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 --- fs/nfsd/blocklayoutxdr.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/nfsd/blocklayoutxdr.c b/fs/nfsd/blocklayoutxdr.c index ca1883668810..6c3b316f932e 100644 --- a/fs/nfsd/blocklayoutxdr.c +++ b/fs/nfsd/blocklayoutxdr.c @@ -105,18 +105,22 @@ nfsd4_block_decode_layoutupdate(__be32 *p, u32 len, struct iomap **iomapp, 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; } -- 2.45.2