4.18-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 07bf7908950a8b14e81aa1807e3c667eab39287a ]
We don't validate the address prefix lengths in the xfrm selector we got from userspace. This can lead to undefined behaviour in the address matching functions if the prefix is too big for the given address family. Fix this by checking the prefixes and refuse SA/policy insertation when a prefix is invalid.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Air Icy icytxw@gmail.com Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/xfrm/xfrm_user.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 33878e6e0d0a..5151b3ebf068 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -151,10 +151,16 @@ static int verify_newsa_info(struct xfrm_usersa_info *p, err = -EINVAL; switch (p->family) { case AF_INET: + if (p->sel.prefixlen_d > 32 || p->sel.prefixlen_s > 32) + goto out; + break;
case AF_INET6: #if IS_ENABLED(CONFIG_IPV6) + if (p->sel.prefixlen_d > 128 || p->sel.prefixlen_s > 128) + goto out; + break; #else err = -EAFNOSUPPORT; @@ -1359,10 +1365,16 @@ static int verify_newpolicy_info(struct xfrm_userpolicy_info *p)
switch (p->sel.family) { case AF_INET: + if (p->sel.prefixlen_d > 32 || p->sel.prefixlen_s > 32) + return -EINVAL; + break;
case AF_INET6: #if IS_ENABLED(CONFIG_IPV6) + if (p->sel.prefixlen_d > 128 || p->sel.prefixlen_s > 128) + return -EINVAL; + break; #else return -EAFNOSUPPORT;