This is a note to let you know that I've just added the patch titled
ipv4: Check attribute length for RTA_GATEWAY in multipath route
to the 5.4-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:
ipv4-check-attribute-length-for-rta_gateway-in-multipath-route.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7a3429bace0e08d94c39245631ea6bc109dafa49 Mon Sep 17 00:00:00 2001
From: David Ahern <dsahern@xxxxxxxxxx>
Date: Thu, 30 Dec 2021 17:36:31 -0700
Subject: ipv4: Check attribute length for RTA_GATEWAY in multipath route
From: David Ahern <dsahern@xxxxxxxxxx>
commit 7a3429bace0e08d94c39245631ea6bc109dafa49 upstream.
syzbot reported uninit-value:
============================================================
BUG: KMSAN: uninit-value in fib_get_nhs+0xac4/0x1f80
net/ipv4/fib_semantics.c:708
fib_get_nhs+0xac4/0x1f80 net/ipv4/fib_semantics.c:708
fib_create_info+0x2411/0x4870 net/ipv4/fib_semantics.c:1453
fib_table_insert+0x45c/0x3a10 net/ipv4/fib_trie.c:1224
inet_rtm_newroute+0x289/0x420 net/ipv4/fib_frontend.c:886
Add helper to validate RTA_GATEWAY length before using the attribute.
Fixes: 4e902c57417c ("[IPv4]: FIB configuration using struct fib_config")
Reported-by: syzbot+d4b9a2851cc3ce998741@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: David Ahern <dsahern@xxxxxxxxxx>
Cc: Thomas Graf <tgraf@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/fib_semantics.c | 29 ++++++++++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -654,6 +654,19 @@ static int fib_count_nexthops(struct rtn
return nhs;
}
+static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
+ struct netlink_ext_ack *extack)
+{
+ if (nla_len(nla) < sizeof(*gw)) {
+ NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
+ return -EINVAL;
+ }
+
+ *gw = nla_get_in_addr(nla);
+
+ return 0;
+}
+
/* only called when fib_nh is integrated into fib_info */
static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
int remaining, struct fib_config *cfg,
@@ -696,7 +709,11 @@ static int fib_get_nhs(struct fib_info *
return -EINVAL;
}
if (nla) {
- fib_cfg.fc_gw4 = nla_get_in_addr(nla);
+ ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
+ extack);
+ if (ret)
+ goto errout;
+
if (fib_cfg.fc_gw4)
fib_cfg.fc_gw_family = AF_INET;
} else if (nlav) {
@@ -894,6 +911,7 @@ int fib_nh_match(struct fib_config *cfg,
attrlen = rtnh_attrlen(rtnh);
if (attrlen > 0) {
struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
+ int err;
nla = nla_find(attrs, attrlen, RTA_GATEWAY);
nlav = nla_find(attrs, attrlen, RTA_VIA);
@@ -904,12 +922,17 @@ int fib_nh_match(struct fib_config *cfg,
}
if (nla) {
+ __be32 gw;
+
+ err = fib_gw_from_attr(&gw, nla, extack);
+ if (err)
+ return err;
+
if (nh->fib_nh_gw_family != AF_INET ||
- nla_get_in_addr(nla) != nh->fib_nh_gw4)
+ gw != nh->fib_nh_gw4)
return 1;
} else if (nlav) {
struct fib_config cfg2;
- int err;
err = fib_gw_from_via(&cfg2, nlav, extack);
if (err)
Patches currently in stable-queue which might be from dsahern@xxxxxxxxxx are
queue-5.4/ipv4-check-attribute-length-for-rta_flow-in-multipath-route.patch
queue-5.4/ipv6-check-attribute-length-for-rta_gateway-when-deleting-multipath-route.patch
queue-5.4/ipv6-check-attribute-length-for-rta_gateway-in-multipath-route.patch
queue-5.4/lwtunnel-validate-rta_encap_type-attribute-length.patch
queue-5.4/ipv4-check-attribute-length-for-rta_gateway-in-multipath-route.patch
