From 4951ffa3fac8892949a09b630191ff12f35f4b72 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Fri, 23 Jul 2021 18:46:01 -0400 Subject: [PATCH] tipc: do not write skb_shinfo frags when doing decrytion [ Upstream commit 3cf4375a090473d240281a0d2b04a3a5aaeac34b ] One skb's skb_shinfo frags are not writable, and they can be shared with other skbs' like by pskb_copy(). To write the frags may cause other skb's data crash. So before doing en/decryption, skb_cow_data() should always be called for a cloned or nonlinear skb if req dst is using the same sg as req src. While at it, the likely branch can be removed, as it will be covered by skb_cow_data(). Note that esp_input() has the same issue, and I will fix it in another patch. tipc_aead_encrypt() doesn't have this issue, as it only processes linear data in the unlikely branch. Fixes: fc1b6d6de220 ("tipc: introduce TIPC encryption & authentication") Reported-by: Shuang Li Signed-off-by: Xin Long Acked-by: Jon Maloy Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/tipc/crypto.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c index 2301b66280de..f8e73c4a0093 100644 --- a/net/tipc/crypto.c +++ b/net/tipc/crypto.c @@ -891,16 +891,10 @@ static int tipc_aead_decrypt(struct net *net, struct tipc_aead *aead, if (unlikely(!aead)) return -ENOKEY; - /* Cow skb data if needed */ - if (likely(!skb_cloned(skb) && - (!skb_is_nonlinear(skb) || !skb_has_frag_list(skb)))) { - nsg = 1 + skb_shinfo(skb)->nr_frags; - } else { - nsg = skb_cow_data(skb, 0, &unused); - if (unlikely(nsg < 0)) { - pr_err("RX: skb_cow_data() returned %d\n", nsg); - return nsg; - } + nsg = skb_cow_data(skb, 0, &unused); + if (unlikely(nsg < 0)) { + pr_err("RX: skb_cow_data() returned %d\n", nsg); + return nsg; } /* Allocate memory for the AEAD operation */