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authorDavid Ahern <dsahern@kernel.org>2021-12-30 17:36:31 -0700
committerDavid S. Miller <davem@davemloft.net>2021-12-31 14:31:59 +0000
commit7a3429bace0e08d94c39245631ea6bc109dafa49 (patch)
treeaf5de5e93bc9b8789398f87bdf7a7414cd1e1652 /net/ipv4/fib_semantics.c
parent74c78b4291b4466b44a57b3b7c3b98ad02628686 (diff)
ipv4: Check attribute length for RTA_GATEWAY in multipath route
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@syzkaller.appspotmail.com Signed-off-by: David Ahern <dsahern@kernel.org> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/fib_semantics.c')
-rw-r--r--net/ipv4/fib_semantics.c29
1 files changed, 26 insertions, 3 deletions
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index fde7797b5806..f1caa2c1c041 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -662,6 +662,19 @@ static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
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,
@@ -704,7 +717,11 @@ static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
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) {
@@ -902,6 +919,7 @@ int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
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);
@@ -912,12 +930,17 @@ int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
}
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)