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| author | David Ahern <dsahern@kernel.org> | 2021-12-30 17:36:31 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-12-31 14:31:59 +0000 |
| commit | 7a3429bace0e08d94c39245631ea6bc109dafa49 (patch) | |
| tree | af5de5e93bc9b8789398f87bdf7a7414cd1e1652 /net/ipv4 | |
| parent | 74c78b4291b4466b44a57b3b7c3b98ad02628686 (diff) | |
| download | linux-stable-7a3429bace0e08d94c39245631ea6bc109dafa49.tar.gz linux-stable-7a3429bace0e08d94c39245631ea6bc109dafa49.tar.bz2 linux-stable-7a3429bace0e08d94c39245631ea6bc109dafa49.zip | |
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')
| -rw-r--r-- | net/ipv4/fib_semantics.c | 29 |
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) |