This is a note to let you know that I've just added the patch titled netfilter: ipset: fix unaligned atomic access to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: netfilter-ipset-fix-unaligned-atomic-access.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0a4813eb66f192d72f35e9c5a84e93831c716afa Author: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> Date: Wed Jun 10 21:51:11 2020 +0100 netfilter: ipset: fix unaligned atomic access [ Upstream commit 715028460082d07a7ec6fcd87b14b46784346a72 ] When using ip_set with counters and comment, traffic causes the kernel to panic on 32-bit ARM: Alignment trap: not handling instruction e1b82f9f at [<bf01b0dc>] Unhandled fault: alignment exception (0x221) at 0xea08133c PC is at ip_set_match_extensions+0xe0/0x224 [ip_set] The problem occurs when we try to update the 64-bit counters - the faulting address above is not 64-bit aligned. The problem occurs due to the way elements are allocated, for example: set->dsize = ip_set_elem_len(set, tb, 0, 0); map = ip_set_alloc(sizeof(*map) + elements * set->dsize); If the element has a requirement for a member to be 64-bit aligned, and set->dsize is not a multiple of 8, but is a multiple of four, then every odd numbered elements will be misaligned - and hitting an atomic64_add() on that element will cause the kernel to panic. ip_set_elem_len() must return a size that is rounded to the maximum alignment of any extension field stored in the element. This change ensures that is the case. Fixes: 95ad1f4a9358 ("netfilter: ipset: Fix extension alignment") Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx> Acked-by: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index 21eb53f6d4fe3..36ebc40a4313c 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -385,6 +385,8 @@ ip_set_elem_len(struct ip_set *set, struct nlattr *tb[], size_t len, for (id = 0; id < IPSET_EXT_ID_MAX; id++) { if (!add_extension(id, cadt_flags, tb)) continue; + if (align < ip_set_extensions[id].align) + align = ip_set_extensions[id].align; len = ALIGN(len, ip_set_extensions[id].align); set->offset[id] = len; set->extensions |= ip_set_extensions[id].type;