From 9b18370ea52be677ada3d0c174b122cc73aa507c Mon Sep 17 00:00:00 2001 From: Nikola Livic Date: Wed, 30 Jun 2021 21:03:24 +0800 Subject: [PATCH] pNFS/flexfiles: fix incorrect size check in decode_nfs_fh() stable inclusion from linux-4.19.191 commit f27638a92f77d8107efbaf48a0d3bfa24da8cdad -------------------------------- [ Upstream commit ed34695e15aba74f45247f1ee2cf7e09d449f925 ] We (adam zabrocki, alexander matrosov, alexander tereshkin, maksym bazalii) observed the check: if (fh->size > sizeof(struct nfs_fh)) should not use the size of the nfs_fh struct which includes an extra two bytes from the size field. struct nfs_fh { unsigned short size; unsigned char data[NFS_MAXFHSIZE]; } but should determine the size from data[NFS_MAXFHSIZE] so the memcpy will not write 2 bytes beyond destination. The proposed fix is to compare against the NFS_MAXFHSIZE directly, as is done elsewhere in fs code base. Fixes: d67ae825a59d ("pnfs/flexfiles: Add the FlexFile Layout Driver") Signed-off-by: Nikola Livic Signed-off-by: Dan Carpenter Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin Signed-off-by: Yang Yingliang --- fs/nfs/flexfilelayout/flexfilelayout.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c index e0fe9a0f1bf1..81843dd8b0ee 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -101,7 +101,7 @@ static int decode_nfs_fh(struct xdr_stream *xdr, struct nfs_fh *fh) if (unlikely(!p)) return -ENOBUFS; fh->size = be32_to_cpup(p++); - if (fh->size > sizeof(struct nfs_fh)) { + if (fh->size > NFS_MAXFHSIZE) { printk(KERN_ERR "NFS flexfiles: Too big fh received %d\n", fh->size); return -EOVERFLOW; -- GitLab