Patchwork [lucid/fsl-imx51,maverick,maverick/ti-omap4,natty/ti-omap4,CVE,1/1] dccp: handle invalid feature options length

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Submitter Andy Whitcroft
Date July 7, 2011, 10:12 p.m.
Message ID <1310076739-23810-2-git-send-email-apw@canonical.com>
Download mbox | patch
Permalink /patch/103736/
State New
Headers show

Comments

Andy Whitcroft - July 7, 2011, 10:12 p.m.
From: Dan Rosenberg <drosenberg@vsecurity.com>

A length of zero (after subtracting two for the type and len fields) for
the DCCPO_{CHANGE,CONFIRM}_{L,R} options will cause an underflow due to
the subtraction.  The subsequent code may read past the end of the
options value buffer when parsing.  I'm unsure of what the consequences
of this might be, but it's probably not good.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: stable@kernel.org
Acked-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

(cherry picked from commit a294865978b701e4d0d90135672749531b9a900d)
CVE-2011-1770
BugLink: http://bugs.launchpad.net/bugs/806375
Signed-off-by: Andy Whitcroft <apw@canonical.com>
---
 net/dccp/options.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

Patch

diff --git a/net/dccp/options.c b/net/dccp/options.c
index 1b08cae..b4a853e 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -131,6 +131,8 @@  int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
 		case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
 			if (pkt_type == DCCP_PKT_DATA)      /* RFC 4340, 6 */
 				break;
+			if (len == 0)
+				goto out_invalid_option;
 			rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
 						    *value, value + 1, len - 1);
 			if (rc)