Linux-NFS Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH v1] SUNRPC: Properly set the @subbuf parameter of xdr_buf_subsegment()
@ 2020-06-25 15:32 Chuck Lever
  0 siblings, 0 replies; only message in thread
From: Chuck Lever @ 2020-06-25 15:32 UTC (permalink / raw)
  To: linux-nfs

@subbuf is an output parameter of xdr_buf_subsegment(). A survey of
call sites shows that @subbuf is always uninitialized before
xdr_buf_segment() is invoked by callers.

There are some execution paths through xdr_buf_subsegment() that do
not set all of the fields in @subbuf, leaving some pointer fields
containing garbage addresses. Subsequent processing of that buffer
then results in a page fault.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: <stable@vger.kernel.org>
---
 net/sunrpc/xdr.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 6f7d82fb1eb0..be11d672b5b9 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -1118,6 +1118,7 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
 		base = 0;
 	} else {
 		base -= buf->head[0].iov_len;
+		subbuf->head[0].iov_base = buf->head[0].iov_base;
 		subbuf->head[0].iov_len = 0;
 	}
 
@@ -1130,6 +1131,8 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
 		base = 0;
 	} else {
 		base -= buf->page_len;
+		subbuf->pages = buf->pages;
+		subbuf->page_base = 0;
 		subbuf->page_len = 0;
 	}
 
@@ -1141,6 +1144,7 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
 		base = 0;
 	} else {
 		base -= buf->tail[0].iov_len;
+		subbuf->tail[0].iov_base = buf->tail[0].iov_base;
 		subbuf->tail[0].iov_len = 0;
 	}
 


^ permalink raw reply	[flat|nested] only message in thread

only message in thread, back to index

Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-25 15:32 [PATCH v1] SUNRPC: Properly set the @subbuf parameter of xdr_buf_subsegment() Chuck Lever

Linux-NFS Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-nfs/0 linux-nfs/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-nfs linux-nfs/ https://lore.kernel.org/linux-nfs \
		linux-nfs@vger.kernel.org
	public-inbox-index linux-nfs

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-nfs


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git