diff options
authorRussell King <>2020-06-10 21:51:11 +0100
committerJozsef Kadlecsik <>2020-09-20 10:36:16 +0200
commit4a27f55bddd345279069eb95ccbe5d9a4224876c (patch)
parente362d76365c583b1390ececbe87e7677019bb098 (diff)
netfiler: ipset: fix unaligned atomic access
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. Signed-off-by: Russell King <> Signed-off-by: Jozsef Kadlecsik <>
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/net/netfilter/ipset/ip_set_core.c b/kernel/net/netfilter/ipset/ip_set_core.c
index 785e387..8026537 100644
--- a/kernel/net/netfilter/ipset/ip_set_core.c
+++ b/kernel/net/netfilter/ipset/ip_set_core.c
@@ -460,6 +460,8 @@ 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))
+ 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;