kernel/linux.git/net/ipv4/esp4.c, branch v5.10.257

xfrm: esp: avoid in-place decrypt on shared skb frags

2026-05-08T10:45:22+00:00

commit f4c50a4034e62ab75f1d5cdd191dd5f9c77fdff4 upstream. MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(), so later paths that may modify packet data can first make a private copy. The IPv4/IPv6 datagram append paths did not set this flag when splicing pages into UDP skbs. That leaves an ESP-in-UDP packet made from shared pipe pages looking like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW fast path for uncloned skbs without a frag_list and decrypts in place over data that is not owned privately by the skb. Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching TCP. Also make ESP input fall back to skb_cow_data() when the flag is present, so ESP does not decrypt externally backed frags in place. Private nonlinear skb frags still use the existing fast path. This intentionally does not change ESP output. In esp_output_head(), the path that appends the ESP trailer to existing skb tailroom without calling skb_cow_data() is not reachable for nonlinear skbs: skb_tailroom() returns zero when skb->data_len is nonzero, while ESP tailen is positive. Thus ESP output will either use the separate destination-frag path or fall back to skb_cow_data(). Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible") Fixes: 7da0dde68486 ("ip, udp: Support MSG_SPLICE_PAGES") Fixes: 6d8192bd69bb ("ip6, udp6: Support MSG_SPLICE_PAGES") Reported-by: Hyunwoo Kim Reported-by: Kuan-Ting Chen Tested-by: Hyunwoo Kim Cc: stable@vger.kernel.org Signed-off-by: Kuan-Ting Chen Signed-off-by: Steffen Klassert [bwh: Backported to 5.10: set the SKBTX_SHARED_FRAG flag in ip_append_page() instead of __ip{,6}_append_data()] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

esp: fix skb leak with espintcp and async crypto

2026-04-18T08:31:04+00:00

[ Upstream commit 0c0eef8ccd2413b0a10eb6bbd3442333b1e64dd2 ] When the TX queue for espintcp is full, esp_output_tail_tcp will return an error and not free the skb, because with synchronous crypto, the common xfrm output code will drop the packet for us. With async crypto (esp_output_done), we need to drop the skb when esp_output_tail_tcp returns an error. Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)") Signed-off-by: Sabrina Dubroca Reviewed-by: Simon Horman Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

xfrm: Fix the usage of skb->sk

2026-04-18T08:31:04+00:00

[ Upstream commit 1620c88887b16940e00dbe57dd38c74eda9bad9e ] xfrm assumed to always have a full socket at skb->sk. This is not always true, so fix it by converting to a full socket before it is used. Signed-off-by: Steffen Klassert Reviewed-by: Eric Dumazet Stable-dep-of: 0c0eef8ccd24 ("esp: fix skb leak with espintcp and async crypto") Signed-off-by: Sasha Levin

net: esp: cleanup esp_output_tail_tcp() in case of unsupported ESPINTCP

2024-08-19T03:40:44+00:00

[ Upstream commit 96f887a612e4cda89efc3f54bc10c1997e3ab0e9 ] xmit() functions should consume skb or return error codes in error paths. When the configuration "CONFIG_INET_ESPINTCP" is not set, the implementation of the function "esp_output_tail_tcp" violates this rule. The function frees the skb and returns the error code. This change removes the kfree_skb from both functions, for both esp4 and esp6. WARN_ON is added because esp_output_tail_tcp() should never be called if CONFIG_INET_ESPINTCP is not set. This bug was discovered and resolved using Coverity Static Analysis Security Testing (SAST) by Synopsys, Inc. Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)") Signed-off-by: Hagar Hemdan Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

net: ipv4: fix return value check in esp_remove_trailer

2023-10-25T09:54:19+00:00

commit 513f61e2193350c7a345da98559b80f61aec4fa6 upstream. In esp_remove_trailer(), to avoid an unexpected result returned by pskb_trim, we should check the return value of pskb_trim(). Signed-off-by: Ma Ke Signed-off-by: Steffen Klassert Signed-off-by: Greg Kroah-Hartman

net: ipv4: Use kfree_sensitive instead of kfree

2023-07-27T06:44:40+00:00

[ Upstream commit daa751444fd9d4184270b1479d8af49aaf1a1ee6 ] key might contain private part of the key, so better use kfree_sensitive to free it. Fixes: 38320c70d282 ("[IPSEC]: Use crypto_aead and authenc in ESP") Signed-off-by: Wang Ming Reviewed-by: Tariq Toukan Reviewed-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

esp: limit skb_page_frag_refill use to a single page

2022-04-27T11:53:48+00:00

[ Upstream commit 5bd8baab087dff657e05387aee802e70304cc813 ] Commit ebe48d368e97 ("esp: Fix possible buffer overflow in ESP transformation") tried to fix skb_page_frag_refill usage in ESP by capping allocsize to 32k, but that doesn't completely solve the issue, as skb_page_frag_refill may return a single page. If that happens, we will write out of bounds, despite the check introduced in the previous patch. This patch forces COW in cases where we would end up calling skb_page_frag_refill with a size larger than a page (first in esp_output_head with tailen, then in esp_output_tail with skb->data_len). Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible") Signed-off-by: Sabrina Dubroca Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin

esp: Fix possible buffer overflow in ESP transformation

2022-03-23T08:13:29+00:00

commit ebe48d368e97d007bfeb76fcb065d6cfc4c96645 upstream. The maximum message size that can be send is bigger than the maximum site that skb_page_frag_refill can allocate. So it is possible to write beyond the allocated buffer. Fix this by doing a fallback to COW in that case. v2: Avoid get get_order() costs as suggested by Linus Torvalds. Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible") Reported-by: valis Signed-off-by: Steffen Klassert Signed-off-by: Tadeusz Struk Signed-off-by: Greg Kroah-Hartman

Revert "xfrm: xfrm_state_mtu should return at least 1280 for ipv6"

2022-03-08T18:09:38+00:00

commit a6d95c5a628a09be129f25d5663a7e9db8261f51 upstream. This reverts commit b515d2637276a3810d6595e10ab02c13bfd0b63a. Commit b515d2637276a3810d6595e10ab02c13bfd0b63a ("xfrm: xfrm_state_mtu should return at least 1280 for ipv6") in v5.14 breaks the TCP MSS calculation in ipsec transport mode, resulting complete stalls of TCP connections. This happens when the (P)MTU is 1280 or slighly larger. The desired formula for the MSS is: MSS = (MTU - ESP_overhead) - IP header - TCP header However, the above commit clamps the (MTU - ESP_overhead) to a minimum of 1280, turning the formula into MSS = max(MTU - ESP overhead, 1280) - IP header - TCP header With the (P)MTU near 1280, the calculated MSS is too large and the resulting TCP packets never make it to the destination because they are over the actual PMTU. The above commit also causes suboptimal double fragmentation in xfrm tunnel mode, as described in https://lore.kernel.org/netdev/20210429202529.codhwpc7w6kbudug@dwarf.suse.cz/ The original problem the above commit was trying to fix is now fixed by commit 6596a0229541270fb8d38d989f91b78838e5e9da ("xfrm: fix MTU regression"). Signed-off-by: Jiri Bohac Signed-off-by: Steffen Klassert Signed-off-by: Greg Kroah-Hartman

xfrm: xfrm_state_mtu should return at least 1280 for ipv6

2021-07-14T14:56:14+00:00

[ Upstream commit b515d2637276a3810d6595e10ab02c13bfd0b63a ] Jianwen reported that IPv6 Interoperability tests are failing in an IPsec case where one of the links between the IPsec peers has an MTU of 1280. The peer generates a packet larger than this MTU, the router replies with a "Packet too big" message indicating an MTU of 1280. When the peer tries to send another large packet, xfrm_state_mtu returns 1280 - ipsec_overhead, which causes ip6_setup_cork to fail with EINVAL. We can fix this by forcing xfrm_state_mtu to return IPV6_MIN_MTU when IPv6 is used. After going through IPsec, the packet will then be fragmented to obey the actual network's PMTU, just before leaving the host. Currently, TFC padding is capped to PMTU - overhead to avoid fragementation: after padding and encapsulation, we still fit within the PMTU. That behavior is preserved in this patch. Fixes: 91657eafb64b ("xfrm: take net hdr len into account for esp payload size calculation") Reported-by: Jianwen Ji Signed-off-by: Sabrina Dubroca Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin