From: Chuck Lever <chuck.lever@oracle.com> stable inclusion from stable-v5.10.220 commit 1726a39b0879acfb490b22dca643f26f4f907da9 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IADG80 CVE: CVE-2022-48827 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 0cb4d23ae08c48f6bf3c29a8e5c4a74b8388b960 ] Dan Aloni reports:

Due to commit 8cfb9015280d ("NFS: Always provide aligned buffers to the RPC read layers") on the client, a read of 0xfff is aligned up to server rsize of 0x1000.

As a result, in a test where the server has a file of size 0x7fffffffffffffff, and the client tries to read from the offset 0x7ffffffffffff000, the read causes loff_t overflow in the server and it returns an NFS code of EINVAL to the client. The client as a result indefinitely retries the request.

The Linux NFS client does not handle NFS?ERR_INVAL, even though all NFS specifications permit servers to return that status code for a READ. Instead of NFS?ERR_INVAL, have out-of-range READ requests succeed and return a short result. Set the EOF flag in the result to prevent the client from retrying the READ request. This behavior appears to be consistent with Solaris NFS servers. Note that NFSv3 and NFSv4 use u64 offset values on the wire. These must be converted to loff_t internally before use -- an implicit type cast is not adequate for this purpose. Otherwise VFS checks against sb->s_maxbytes do not work properly. Reported-by: Dan Aloni <dan.aloni@vastdata.com> Cc: stable@vger.kernel.org Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Conflicts: fs/nfsd/nfs3proc.c [Commit be63bd2ac6bb("NFSD: Update READ3arg decoder to use struct xdr_stream") modified the method of initializing resp->count] Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com> --- fs/nfsd/nfs3proc.c | 8 ++++++-- fs/nfsd/nfs4proc.c | 8 ++++++-- fs/nfsd/nfs4xdr.c | 8 ++------ 3 files changed, 14 insertions(+), 10 deletions(-) diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c index 981a4e4c9a3c..0b61080d6234 100644 --- a/fs/nfsd/nfs3proc.c +++ b/fs/nfsd/nfs3proc.c @@ -145,18 +145,22 @@ nfsd3_proc_read(struct svc_rqst *rqstp) struct nfsd3_readargs *argp = rqstp->rq_argp; struct nfsd3_readres *resp = rqstp->rq_resp; u32 max_blocksize = svc_max_payload(rqstp); - unsigned long cnt = min(argp->count, max_blocksize); dprintk("nfsd: READ(3) %s %lu bytes at %Lu\n", SVCFH_fmt(&argp->fh), (unsigned long) argp->count, (unsigned long long) argp->offset); + argp->count = min_t(u32, argp->count, max_blocksize); + if (argp->offset > (u64)OFFSET_MAX) + argp->offset = (u64)OFFSET_MAX; + if (argp->offset + argp->count > (u64)OFFSET_MAX) + argp->count = (u64)OFFSET_MAX - argp->offset; /* Obtain buffer pointer for payload. * 1 (status) + 22 (post_op_attr) + 1 (count) + 1 (eof) * + 1 (xdr opaque byte count) = 26 */ - resp->count = cnt; + resp->count = argp->count; svc_reserve_auth(rqstp, ((1 + NFS3_POST_OP_ATTR_WORDS + 3)<<2) + resp->count +4); fh_copy(&resp->fh, &argp->fh); diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index e84996c3867c..41dc517c934f 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -772,12 +772,16 @@ nfsd4_read(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, __be32 status; read->rd_nf = NULL; - if (read->rd_offset >= OFFSET_MAX) - return nfserr_inval; trace_nfsd_read_start(rqstp, &cstate->current_fh, read->rd_offset, read->rd_length); + read->rd_length = min_t(u32, read->rd_length, svc_max_payload(rqstp)); + if (read->rd_offset > (u64)OFFSET_MAX) + read->rd_offset = (u64)OFFSET_MAX; + if (read->rd_offset + read->rd_length > (u64)OFFSET_MAX) + read->rd_length = (u64)OFFSET_MAX - read->rd_offset; + /* * If we do a zero copy read, then a client will see read data * that reflects the state of the file *after* performing the diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index dbfa24cf3390..1c11042dafb8 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -3886,10 +3886,8 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr, } xdr_commit_encode(xdr); - maxcount = svc_max_payload(resp->rqstp); - maxcount = min_t(unsigned long, maxcount, + maxcount = min_t(unsigned long, read->rd_length, (xdr->buf->buflen - xdr->buf->len)); - maxcount = min_t(unsigned long, maxcount, read->rd_length); if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags)) @@ -4714,10 +4712,8 @@ nfsd4_encode_read_plus(struct nfsd4_compoundres *resp, __be32 nfserr, return nfserr_resource; xdr_commit_encode(xdr); - maxcount = svc_max_payload(resp->rqstp); - maxcount = min_t(unsigned long, maxcount, + maxcount = min_t(unsigned long, read->rd_length, (xdr->buf->buflen - xdr->buf->len)); - maxcount = min_t(unsigned long, maxcount, read->rd_length); count = maxcount; eof = read->rd_offset >= i_size_read(file_inode(file)); -- 2.31.1