leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

SUNRPC: Fix svcxdr_init_encode's buflen calculation

Browse Source 
Commit 2825a7f907 ("nfsd4: allow encoding across page boundaries")
added an explicit computation of the remaining length in the rq_res
XDR buffer.

The computation appears to suffer from an "off-by-one" bug. Because
buflen is too large by one page, XDR encoding can run off the end of
the send buffer by eventually trying to use the struct page address
in rq_page_end, which always contains NULL.

Fixes: bddfdbcddb ("NFSD: Extract the svcxdr_init_encode() helper")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2022-09-01 15:09:59 -04:00
parent 90bfc37b5a
commit 1242a87da0
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/sunrpc/svc.h
View File

@ -587,7 +587,7 @@ static inline void svcxdr_init_encode(struct svc_rqst *rqstp)
xdr->end = resv->iov_base + PAGE_SIZE - rqstp->rq_auth_slack; xdr->end = resv->iov_base + PAGE_SIZE - rqstp->rq_auth_slack;
buf->len = resv->iov_len; buf->len = resv->iov_len;
xdr->page_ptr = buf->pages - 1; xdr->page_ptr = buf->pages - 1;
buf->buflen = PAGE_SIZE * (1 + rqstp->rq_page_end - buf->pages); buf->buflen = PAGE_SIZE * (rqstp->rq_page_end - buf->pages);
buf->buflen -= rqstp->rq_auth_slack; buf->buflen -= rqstp->rq_auth_slack;
xdr->rqst = NULL; xdr->rqst = NULL;
} }