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NFSv4.2: Don't error when exiting early on a READ_PLUS buffer overflow 

[ Upstream commit 503b934a75 ]

Expanding the READ_PLUS extents can cause the read buffer to overflow.
If it does, then don't error, but just exit early.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
pull/210/head
Trond Myklebust 2020-12-08 07:51:29 -05:00 committed by Greg Kroah-Hartman
parent ef3b9ad967
commit 8bcfa178f9
1 changed files with 17 additions and 19 deletions
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36
fs/nfs/nfs42xdr.c
View File

@ -1019,29 +1019,24 @@ static int decode_deallocate(struct xdr_stream *xdr, struct nfs42_falloc_res *re
return decode_op_hdr(xdr, OP_DEALLOCATE);
}
static int decode_read_plus_data(struct xdr_stream *xdr, struct nfs_pgio_res *res,
uint32_t *eof)
static int decode_read_plus_data(struct xdr_stream *xdr,
struct nfs_pgio_res *res)
{
uint32_t count, recvd;
uint64_t offset;
__be32 *p;
p = xdr_inline_decode(xdr, 8 + 4);
if (unlikely(!p))
return -EIO;
if (!p)
return 1;
p = xdr_decode_hyper(p, &offset);
count = be32_to_cpup(p);
recvd = xdr_align_data(xdr, res->count, count);
res->count += recvd;
if (count > recvd) {
dprintk("NFS: server cheating in read reply: "
"count %u > recvd %u\n", count, recvd);
*eof = 0;
if (count > recvd)
return 1;
}
return 0;
}
@ -1052,18 +1047,16 @@ static int decode_read_plus_hole(struct xdr_stream *xdr, struct nfs_pgio_res *re
__be32 *p;
p = xdr_inline_decode(xdr, 8 + 8);
if (unlikely(!p))
return -EIO;
if (!p)
return 1;
p = xdr_decode_hyper(p, &offset);
p = xdr_decode_hyper(p, &length);
recvd = xdr_expand_hole(xdr, res->count, length);
res->count += recvd;
if (recvd < length) {
*eof = 0;
if (recvd < length)
return 1;
}
return 0;
}
@ -1088,12 +1081,12 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res)
for (i = 0; i < segments; i++) {
p = xdr_inline_decode(xdr, 4);
if (unlikely(!p))
return -EIO;
if (!p)
goto early_out;
type = be32_to_cpup(p++);
if (type == NFS4_CONTENT_DATA)
status = decode_read_plus_data(xdr, res, &eof);
status = decode_read_plus_data(xdr, res);
else if (type == NFS4_CONTENT_HOLE)
status = decode_read_plus_hole(xdr, res, &eof);
else
@ -1102,12 +1095,17 @@ static int decode_read_plus(struct xdr_stream *xdr, struct nfs_pgio_res *res)
if (status < 0)
return status;
if (status > 0)
break;
goto early_out;
}
out:
res->eof = eof;
return 0;
early_out:
if (unlikely(!i))
return -EIO;
res->eof = 0;
return 0;
}
static int decode_seek(struct xdr_stream *xdr, struct nfs42_seek_res *res)