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| author | Michal Hocko <mhocko@kernel.org> | 2018-01-30 11:30:11 -0800 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2018-02-02 12:45:16 +0100 |
| commit | 0537250fdc6c876ed4cbbe874c739aebef493ee2 (patch) | |
| tree | 849e9a9c317dcbb325eda7d8a81bc3615f473470 | |
| parent | 743ffffefac1c670c6618742c923f6275d819604 (diff) | |
| download | op-kernel-dev-0537250fdc6c876ed4cbbe874c739aebef493ee2.zip op-kernel-dev-0537250fdc6c876ed4cbbe874c739aebef493ee2.tar.gz | |
netfilter: x_tables: make allocation less aggressive
syzbot has noticed that xt_alloc_table_info can allocate a lot of memory.
This is an admin only interface but an admin in a namespace is sufficient
as well. eacd86ca3b03 ("net/netfilter/x_tables.c: use kvmalloc() in
xt_alloc_table_info()") has changed the opencoded kmalloc->vmalloc
fallback into kvmalloc. It has dropped __GFP_NORETRY on the way because
vmalloc has simply never fully supported __GFP_NORETRY semantic. This is
still the case because e.g. page tables backing the vmalloc area are
hardcoded GFP_KERNEL.
Revert back to __GFP_NORETRY as a poors man defence against excessively
large allocation request here. We will not rule out the OOM killer
completely but __GFP_NORETRY should at least stop the large request in
most cases.
[akpm@linux-foundation.org: coding-style fixes]
Fixes: eacd86ca3b03 ("net/netfilter/x_tables.c: use kvmalloc() in xt_alloc_tableLink: http://lkml.kernel.org/r/20180130140104.GE21609@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | net/netfilter/x_tables.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 8fa4d37..2f685ee 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -1008,7 +1008,12 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size) if ((size >> PAGE_SHIFT) + 2 > totalram_pages) return NULL; - info = kvmalloc(sz, GFP_KERNEL); + /* __GFP_NORETRY is not fully supported by kvmalloc but it should + * work reasonably well if sz is too large and bail out rather + * than shoot all processes down before realizing there is nothing + * more to reclaim. + */ + info = kvmalloc(sz, GFP_KERNEL | __GFP_NORETRY); if (!info) return NULL; |
