kernel/net/ipv6/seg6_hmac.c, branch master

ipv6: add NULL checks for idev in SRv6 paths

2026-03-19T00:23:43Z

__in6_dev_get() can return NULL when the device has no IPv6 configuration (e.g. MTU < IPV6_MIN_MTU or after NETDEV_UNREGISTER). Add NULL checks for idev returned by __in6_dev_get() in both seg6_hmac_validate_skb() and ipv6_srh_rcv() to prevent potential NULL pointer dereferences. Fixes: 1ababeba4a21 ("ipv6: implement dataplane support for rthdr type 4 (Segment Routing Header)") Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support") Signed-off-by: Minhong He Reviewed-by: Andrea Mayer Link: https://patch.msgid.link/20260316073301.106643-1-heminhong@kylinos.cn Signed-off-by: Jakub Kicinski

ipv6: sr: Prepare HMAC key ahead of time

2025-08-27T01:11:29Z

Prepare the HMAC key when it is added to the kernel, instead of preparing it implicitly for every packet. This significantly improves the performance of seg6_hmac_compute(). A microbenchmark on x86_64 shows seg6_hmac_compute() (with HMAC-SHA256) dropping from ~1978 cycles to ~1419 cycles, a 28% improvement. The size of 'struct seg6_hmac_info' increases by 128 bytes, but that should be fine, since there should not be a massive number of keys. Signed-off-by: Eric Biggers Link: https://patch.msgid.link/20250824013644.71928-3-ebiggers@kernel.org Signed-off-by: Jakub Kicinski

ipv6: sr: Use HMAC-SHA1 and HMAC-SHA256 library functions

2025-08-27T01:11:29Z

Use the HMAC-SHA1 and HMAC-SHA256 library functions instead of crypto_shash. This is simpler and faster. Pre-allocating per-CPU hash transformation objects and descriptors is no longer needed, and a microbenchmark on x86_64 shows seg6_hmac_compute() (with HMAC-SHA256) dropping from ~2494 cycles to ~1978 cycles, a 20% improvement. Signed-off-by: Eric Biggers Link: https://patch.msgid.link/20250824013644.71928-2-ebiggers@kernel.org Signed-off-by: Jakub Kicinski

ipv6: sr: Fix MAC comparison to be constant-time

2025-08-21T02:32:30Z

To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this. Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Reviewed-by: Andrea Mayer Link: https://patch.msgid.link/20250818202724.15713-1-ebiggers@kernel.org Signed-off-by: Jakub Kicinski

ipv6: sr: validate HMAC algorithm ID in seg6_hmac_info_add

2025-08-19T00:35:50Z

The seg6_genl_sethmac() directly uses the algorithm ID provided by the userspace without verifying whether it is an HMAC algorithm supported by the system. If an unsupported HMAC algorithm ID is configured, packets using SRv6 HMAC will be dropped during encapsulation or decapsulation. Fixes: 4f4853dc1c9c ("ipv6: sr: implement API to control SR HMAC structure") Signed-off-by: Minhong He Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250815063845.85426-1-heminhong@kylinos.cn Signed-off-by: Jakub Kicinski

ipv6: sr: Use nested-BH locking for hmac_storage

2025-05-15T13:23:31Z

hmac_storage is a per-CPU variable and relies on disabled BH for its locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT this data structure requires explicit locking. Add a local_lock_t to the data structure and use local_lock_nested_bh() for locking. This change adds only lockdep coverage and does not alter the functional behaviour for !PREEMPT_RT. Cc: David Ahern Signed-off-by: Sebastian Andrzej Siewior Link: https://patch.msgid.link/20250512092736.229935-5-bigeasy@linutronix.de Signed-off-by: Paolo Abeni

ipv6: sr: fix memleak in seg6_hmac_init_algo

2024-05-21T11:16:25Z

seg6_hmac_init_algo returns without cleaning up the previous allocations if one fails, so it's going to leak all that memory and the crypto tfms. Update seg6_hmac_exit to only free the memory when allocated, so we can reuse the code directly. Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support") Reported-by: Sabrina Dubroca Closes: https://lore.kernel.org/netdev/Zj3bh-gE7eT6V6aH@hog/ Signed-off-by: Hangbin Liu Reviewed-by: Simon Horman Reviewed-by: Sabrina Dubroca Link: https://lore.kernel.org/r/20240517005435.2600277-1-liuhangbin@gmail.com Signed-off-by: Paolo Abeni

ipv6/addrconf: annotate data-races around devconf fields (II)

2024-03-01T08:42:33Z

Final (?) round of this series. Annotate lockless reads on following devconf fields, because they be changed concurrently from /proc/net/ipv6/conf. - accept_dad - optimistic_dad - use_optimistic - use_oif_addrs_only - ra_honor_pio_life - keep_addr_on_down - ndisc_notify - ndisc_evict_nocarrier - suppress_frag_ndisc - addr_gen_mode - seg6_enabled - ioam6_enabled - ioam6_id - ioam6_id_wide - drop_unicast_in_l2_multicast - mldv[12]_unsolicited_report_interval - force_mld_version - force_tllao - accept_untracked_na - drop_unsolicited_na - accept_source_route Signed-off-by: Eric Dumazet Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller

net: ipv6: unexport __init-annotated seg6_hmac_net_init()

2022-06-29T04:23:30Z

As of commit 5801f064e351 ("net: ipv6: unexport __init-annotated seg6_hmac_init()"), EXPORT_SYMBOL and __init is a bad combination because the .init.text section is freed up after the initialization. Hence, modules cannot use symbols annotated __init. The access to a freed symbol may end up with kernel panic. This remove the EXPORT_SYMBOL to fix modpost warning: WARNING: modpost: vmlinux.o(___ksymtab+seg6_hmac_net_init+0x0): Section mismatch in reference from the variable __ksymtab_seg6_hmac_net_init to the function .init.text:seg6_hmac_net_init() The symbol seg6_hmac_net_init is exported and annotated __init Fix this by removing the __init annotation of seg6_hmac_net_init or drop the export. Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support") Reported-by: Hulk Robot Signed-off-by: YueHaibing Link: https://lore.kernel.org/r/20220628033134.21088-1-yuehaibing@huawei.com Signed-off-by: Jakub Kicinski

net: ipv6: unexport __init-annotated seg6_hmac_init()

2022-06-08T17:10:14Z

EXPORT_SYMBOL and __init is a bad combination because the .init.text section is freed up after the initialization. Hence, modules cannot use symbols annotated __init. The access to a freed symbol may end up with kernel panic. modpost used to detect it, but it has been broken for a decade. Recently, I fixed modpost so it started to warn it again, then this showed up in linux-next builds. There are two ways to fix it: - Remove __init - Remove EXPORT_SYMBOL I chose the latter for this case because the caller (net/ipv6/seg6.c) and the callee (net/ipv6/seg6_hmac.c) belong to the same module. It seems an internal function call in ipv6.ko. Fixes: bf355b8d2c30 ("ipv6: sr: add core files for SR HMAC support") Reported-by: Stephen Rothwell Signed-off-by: Masahiro Yamada Signed-off-by: Jakub Kicinski