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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Chuck Lever <chuck.lever@oracle.com>,
	Benjamin Coddington <bcodding@redhat.com>,
	Trond Myklebust <trond.myklebust@hammerspace.com>,
	Sasha Levin <sashal@kernel.org>,
	linux-nfs@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.4 149/205] SUNRPC: Fix another issue with MIC buffer space
Date: Thu, 16 Jan 2020 11:42:04 -0500
Message-ID: <20200116164300.6705-149-sashal@kernel.org> (raw)
In-Reply-To: <20200116164300.6705-1-sashal@kernel.org>

From: Chuck Lever <chuck.lever@oracle.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@oracle.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.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


  parent reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200116164300.6705-1-sashal@kernel.org>
2020-01-16 16:40 ` [PATCH AUTOSEL 5.4 058/205] xprtrdma: Connection becomes unstable after a reconnect Sasha Levin
2020-01-16 16:40 ` [PATCH AUTOSEL 5.4 059/205] xprtrdma: Fix MR list handling Sasha Levin
2020-01-16 16:40 ` [PATCH AUTOSEL 5.4 083/205] SUNRPC: Fix svcauth_gss_proxy_init() Sasha Levin
2020-01-16 16:41 ` [PATCH AUTOSEL 5.4 133/205] nfsd: Fix cld_net->cn_tfm initialization Sasha Levin
2020-01-16 16:41 ` [PATCH AUTOSEL 5.4 134/205] nfsd: v4 support requires CRYPTO_SHA256 Sasha Levin
2020-01-16 16:41 ` [PATCH AUTOSEL 5.4 140/205] NFSv4.x: Handle bad/dead sessions correctly in nfs41_sequence_process() Sasha Levin
2020-01-16 16:42 ` Sasha Levin [this message]
2020-01-16 16:42 ` [PATCH AUTOSEL 5.4 165/205] SUNRPC: Fix backchannel latency metrics Sasha Levin
2020-01-16 16:42 ` [PATCH AUTOSEL 5.4 198/205] NFSD fixing possible null pointer derefering in copy offload Sasha Levin
2020-01-16 16:42 ` [PATCH AUTOSEL 5.4 199/205] nfsd: depend on CRYPTO_MD5 for legacy client tracking Sasha Levin

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