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| author | Russell King <rmk+kernel@armlinux.org.uk> | 2020-06-10 21:51:11 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2020-06-25 00:49:48 +0200 |
| commit | 715028460082d07a7ec6fcd87b14b46784346a72 (patch) | |
| tree | 8a5abd941d14e62741b095e45b97d8d805f8b2fd /net/netfilter | |
| parent | 67c20de35a3cc2e2cd940f95ebd85ed0a765315a (diff) | |
| download | linux-stable-715028460082d07a7ec6fcd87b14b46784346a72.tar.gz linux-stable-715028460082d07a7ec6fcd87b14b46784346a72.tar.bz2 linux-stable-715028460082d07a7ec6fcd87b14b46784346a72.zip | |
netfilter: 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.
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>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/ipset/ip_set_core.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c index 340cb955af25..56621d6bfd29 100644 --- a/net/netfilter/ipset/ip_set_core.c +++ b/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)) 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; |