From 3181bac135b7cf9c23f7755f5e207e5ec2c50054 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Tue, 25 Jan 2022 16:36:22 -0500 Subject: [PATCH] NFSD: Clamp WRITE offsets BugLink: https://bugs.launchpad.net/bugs/1966118 commit 6260d9a56ab352b54891ec66ab0eced57d55abc6 upstream. Ensure that a client cannot specify a WRITE range that falls in a byte range outside what the kernel's internal types (such as loff_t, which is signed) can represent. The kiocb iterators, invoked in nfsd_vfs_write(), should properly limit write operations to within the underlying file system's s_maxbytes. Cc: stable@vger.kernel.org Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Stefan Bader --- fs/nfsd/nfs3proc.c | 5 +++++ fs/nfsd/nfs4proc.c | 5 +++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c index cea68d8411ac..bb97c020c96b 100644 --- a/fs/nfsd/nfs3proc.c +++ b/fs/nfsd/nfs3proc.c @@ -195,6 +195,11 @@ nfsd3_proc_write(struct svc_rqst *rqstp) (unsigned long long) argp->offset, argp->stable? " stable" : ""); + resp->status = nfserr_fbig; + if (argp->offset > (u64)OFFSET_MAX || + argp->offset + argp->len > (u64)OFFSET_MAX) + return rpc_success; + fh_copy(&resp->fh, &argp->fh); resp->committed = argp->stable; nvecs = svc_fill_write_vector(rqstp, rqstp->rq_arg.pages, diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index 4798667af647..452ed633a2c7 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -992,8 +992,9 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, unsigned long cnt; int nvecs; - if (write->wr_offset >= OFFSET_MAX) - return nfserr_inval; + if (write->wr_offset > (u64)OFFSET_MAX || + write->wr_offset + write->wr_buflen > (u64)OFFSET_MAX) + return nfserr_fbig; cnt = write->wr_buflen; trace_nfsd_write_start(rqstp, &cstate->current_fh, -- 2.39.5