| From | Greg Kroah-Hartman <> | Subject | [ 11/84] xfrm_user: return error pointer instead of NULL | Date | Thu, 11 Oct 2012 11:02:55 +0900 |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Mathias Krause <minipli@googlemail.com>
[ Upstream commit 864745d291b5ba80ea0bd0edcbe67273de368836 ]
When dump_one_state() returns an error, e.g. because of a too small buffer to dump the whole xfrm state, xfrm_state_netlink() returns NULL instead of an error pointer. But its callers expect an error pointer and therefore continue to operate on a NULL skbuff.
This could lead to a privilege escalation (execution of user code in kernel context) if the attacker has CAP_NET_ADMIN and is able to map address 0.
Signed-off-by: Mathias Krause <minipli@googlemail.com> Acked-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/xfrm/xfrm_user.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -862,6 +862,7 @@ static struct sk_buff *xfrm_state_netlin { struct xfrm_dump_info info; struct sk_buff *skb; + int err; skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC); if (!skb) @@ -872,9 +873,10 @@ static struct sk_buff *xfrm_state_netlin info.nlmsg_seq = seq; info.nlmsg_flags = 0; - if (dump_one_state(x, 0, &info)) { + err = dump_one_state(x, 0, &info); + if (err) { kfree_skb(skb); - return NULL; + return ERR_PTR(err); } return skb;
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