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Patch "svcrpc: fix potential GSSX_ACCEPT_SEC_CONTEXT decoding failures" has been added to the 3.14-stable tree

PATCH [email protected] 1 participant 1 message Jun 3, 2015

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This is a note to let you know that I've just added the patch titled

svcrpc: fix potential GSSX_ACCEPT_SEC_CONTEXT decoding failures

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
svcrpc-fix-potential-gssx_accept_sec_context-decoding-failures.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 9507271d960a1911a51683888837d75c171cd91f Mon Sep 17 00:00:00 2001

From: Scott Mayhew <[email protected]>
Date: Tue, 28 Apr 2015 16:29:53 -0400
Subject: svcrpc: fix potential GSSX_ACCEPT_SEC_CONTEXT decoding failures

From: Scott Mayhew <[email protected]>

commit 9507271d960a1911a51683888837d75c171cd91f upstream.

In an environment where the KDC is running Active Directory, the exported composite name field returned in the context could be large enough to span a page boundary. Attaching a scratch buffer to the decoding xdr_stream helps deal with those cases.

The case where we saw this was actually due to behavior that's been fixed in newer gss-proxy versions, but we're fixing it here too.

Signed-off-by Scott Mayhew <[email protected]>
Reviewed-by Simo Sorce <[email protected]>
Signed-off-by J. Bruce Fields <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 net/sunrpc/auth_gss/gss_rpc_xdr.c |   23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)
net/sunrpc/auth_gss/gss_rpc_xdr.c +16 -7
@@ -793,20 +793,26 @@ int gssx_dec_accept_sec_context(struct r
 {
 	u32 value_follows;
 	int err;
+	struct page *scratch;
+
+	scratch = alloc_page(GFP_KERNEL);
+	if (!scratch)
+		return -ENOMEM;
+	xdr_set_scratch_buffer(xdr, page_address(scratch), PAGE_SIZE);
 
 	/* res->status */
 	err = gssx_dec_status(xdr, &res->status);
 	if (err)
-		return err;
+		goto out_free;
 
 	/* res->context_handle */
 	err = gssx_dec_bool(xdr, &value_follows);
 	if (err)
-		return err;
+		goto out_free;
 	if (value_follows) {
 		err = gssx_dec_ctx(xdr, res->context_handle);
 		if (err)
-			return err;
+			goto out_free;
 	} else {
 		res->context_handle = NULL;
 	}

@@ -814,11 +820,11 @@ int gssx_dec_accept_sec_context(struct r
 	/* res->output_token */
 	err = gssx_dec_bool(xdr, &value_follows);
 	if (err)
-		return err;
+		goto out_free;
 	if (value_follows) {
 		err = gssx_dec_buffer(xdr, res->output_token);
 		if (err)
-			return err;
+			goto out_free;
 	} else {
 		res->output_token = NULL;
 	}

@@ -826,14 +832,17 @@ int gssx_dec_accept_sec_context(struct r
 	/* res->delegated_cred_handle */
 	err = gssx_dec_bool(xdr, &value_follows);
 	if (err)
-		return err;
+		goto out_free;
 	if (value_follows) {
 		/* we do not support upcall servers sending this data. */
-		return -EINVAL;
+		err = -EINVAL;
+		goto out_free;
 	}
 
 	/* res->options */
 	err = gssx_dec_option_array(xdr, &res->options);
 
+out_free:
+	__free_page(scratch);
 	return err;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/svcrpc-fix-potential-gssx_accept_sec_context-decoding-failures.patch