This is a note to let you know that I've just added the patch titled
nfsd: Limit end of page list when decoding NFSv4 WRITE
to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-limit-end-of-page-list-when-decoding-nfsv4-write.patch
and it can be found in the queue-4.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From fc788f64f1f3eb31e87d4f53bcf1ab76590d5838 Mon Sep 17 00:00:00 2001
From: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Fri, 18 Aug 2017 11:12:19 -0400
Subject: nfsd: Limit end of page list when decoding NFSv4 WRITE
From: Chuck Lever <chuck.lever@xxxxxxxxxx>
commit fc788f64f1f3eb31e87d4f53bcf1ab76590d5838 upstream.
When processing an NFSv4 WRITE operation, argp->end should never
point past the end of the data in the final page of the page list.
Otherwise, nfsd4_decode_compound can walk into uninitialized memory.
More critical, nfsd4_decode_write is failing to increment argp->pagelen
when it increments argp->pagelist. This can cause later xdr decoders
to assume more data is available than really is, which can cause server
crashes on malformed requests.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4xdr.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -144,7 +144,7 @@ static void next_decode_page(struct nfsd
argp->p = page_address(argp->pagelist[0]);
argp->pagelist++;
if (argp->pagelen < PAGE_SIZE) {
- argp->end = argp->p + (argp->pagelen>>2);
+ argp->end = argp->p + XDR_QUADLEN(argp->pagelen);
argp->pagelen = 0;
} else {
argp->end = argp->p + (PAGE_SIZE>>2);
@@ -1279,9 +1279,7 @@ nfsd4_decode_write(struct nfsd4_compound
argp->pagelen -= pages * PAGE_SIZE;
len -= pages * PAGE_SIZE;
- argp->p = (__be32 *)page_address(argp->pagelist[0]);
- argp->pagelist++;
- argp->end = argp->p + XDR_QUADLEN(PAGE_SIZE);
+ next_decode_page(argp);
}
argp->p += XDR_QUADLEN(len);
Patches currently in stable-queue which might be from chuck.lever@xxxxxxxxxx are
queue-4.12/nfsd-limit-end-of-page-list-when-decoding-nfsv4-write.patch