From 254ba7e6032d3fc738050d500b0c1d8197af90ca Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 27 Feb 2025 20:23:27 -0800 Subject: [PATCH] ipv4: fib: Move fib_valid_key_len() to rtm_to_fib_config(). fib_valid_key_len() is called in the beginning of fib_table_insert() or fib_table_delete() to check if the prefix length is valid. fib_table_insert() and fib_table_delete() are called from 3 paths - ip_rt_ioctl() - inet_rtm_newroute() / inet_rtm_delroute() - fib_magic() In the first ioctl() path, rtentry_to_fib_config() checks the prefix length with bad_mask(). Also, fib_magic() always passes the correct prefix: 32 or ifa->ifa_prefixlen, which is already validated. Let's move fib_valid_key_len() to the rtnetlink path, rtm_to_fib_config(). While at it, 2 direct returns in rtm_to_fib_config() are changed to goto to match other places in the same function Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: David Ahern Link: https://patch.msgid.link/20250228042328.96624-12-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- net/ipv4/fib_frontend.c | 18 ++++++++++++++++-- net/ipv4/fib_trie.c | 22 ---------------------- 2 files changed, 16 insertions(+), 24 deletions(-) diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index a76dacc3e577..a6372d934e45 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -835,19 +835,33 @@ static int rtm_to_fib_config(struct net *net, struct sk_buff *skb, } } + if (cfg->fc_dst_len > 32) { + NL_SET_ERR_MSG(extack, "Invalid prefix length"); + err = -EINVAL; + goto errout; + } + + if (cfg->fc_dst_len < 32 && (ntohl(cfg->fc_dst) << cfg->fc_dst_len)) { + NL_SET_ERR_MSG(extack, "Invalid prefix for given prefix length"); + err = -EINVAL; + goto errout; + } + if (cfg->fc_nh_id) { if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_encap || cfg->fc_mp) { NL_SET_ERR_MSG(extack, "Nexthop specification and nexthop id are mutually exclusive"); - return -EINVAL; + err = -EINVAL; + goto errout; } } if (has_gw && has_via) { NL_SET_ERR_MSG(extack, "Nexthop configuration can not contain both GATEWAY and VIA"); - return -EINVAL; + err = -EINVAL; + goto errout; } if (!cfg->fc_table) diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index d6411ac81096..59a6f0a9638f 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -1187,22 +1187,6 @@ static int fib_insert_alias(struct trie *t, struct key_vector *tp, return 0; } -static bool fib_valid_key_len(u32 key, u8 plen, struct netlink_ext_ack *extack) -{ - if (plen > KEYLENGTH) { - NL_SET_ERR_MSG(extack, "Invalid prefix length"); - return false; - } - - if ((plen < KEYLENGTH) && (key << plen)) { - NL_SET_ERR_MSG(extack, - "Invalid prefix for given prefix length"); - return false; - } - - return true; -} - static void fib_remove_alias(struct trie *t, struct key_vector *tp, struct key_vector *l, struct fib_alias *old); @@ -1223,9 +1207,6 @@ int fib_table_insert(struct net *net, struct fib_table *tb, key = ntohl(cfg->fc_dst); - if (!fib_valid_key_len(key, plen, extack)) - return -EINVAL; - pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen); fi = fib_create_info(cfg, extack); @@ -1717,9 +1698,6 @@ int fib_table_delete(struct net *net, struct fib_table *tb, key = ntohl(cfg->fc_dst); - if (!fib_valid_key_len(key, plen, extack)) - return -EINVAL; - l = fib_find_node(t, &tp, key); if (!l) return -ESRCH; -- 2.50.1