linux-kernel - [PATCH AUTOSEL 5.4 149/205] SUNRPC: Fix another issue with MIC buffer space

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200116164300.6705-149-sashal@kernel.org>
Date:   Thu, 16 Jan 2020 11:42:04 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Chuck Lever <chuck.lever@...cle.com>,
        Benjamin Coddington <bcodding@...hat.com>,
        Trond Myklebust <trond.myklebust@...merspace.com>,
        Sasha Levin <sashal@...nel.org>, linux-nfs@...r.kernel.org,
        netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 5.4 149/205] SUNRPC: Fix another issue with MIC buffer space

From: Chuck Lever <chuck.lever@...cle.com>

[ Upstream commit e8d70b321ecc9b23d09b8df63e38a2f73160c209 ]

xdr_shrink_pagelen() BUG's when @len is larger than buf->page_len.
This can happen when xdr_buf_read_mic() is given an xdr_buf with
a small page array (like, only a few bytes).

Instead, just cap the number of bytes that xdr_shrink_pagelen()
will move.

Fixes: 5f1bc39979d ("SUNRPC: Fix buffer handling of GSS MIC ... ")
Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
Reviewed-by: Benjamin Coddington <bcodding@...hat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@...merspace.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/sunrpc/xdr.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 14ba9e72a204..f3104be8ff5d 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -436,13 +436,12 @@ xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
 }
 
 /**
- * xdr_shrink_pagelen
+ * xdr_shrink_pagelen - shrinks buf->pages by up to @len bytes
  * @buf: xdr_buf
  * @len: bytes to remove from buf->pages
  *
- * Shrinks XDR buffer's page array buf->pages by
- * 'len' bytes. The extra data is not lost, but is instead
- * moved into the tail.
+ * The extra data is not lost, but is instead moved into buf->tail.
+ * Returns the actual number of bytes moved.
  */
 static unsigned int
 xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
@@ -455,8 +454,8 @@ xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
 
 	result = 0;
 	tail = buf->tail;
-	BUG_ON (len > pglen);
-
+	if (len > buf->page_len)
+		len = buf-> page_len;
 	tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
 
 	/* Shift the tail first */
-- 
2.20.1