From: Russell King rmk+kernel@armlinux.org.uk
[ 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@armlinux.org.uk Acked-by: Jozsef Kadlecsik kadlec@netfilter.org Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/ipset/ip_set_core.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index c2b21c9c12295..5c59bbad8d193 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/net/netfilter/ipset/ip_set_core.c @@ -381,6 +381,8 @@ 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;