hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

netfilter: x_tables: do not fail xt_alloc_table_info too easilly 

eacd86ca3b ("net/netfilter/x_tables.c: use kvmalloc()
in xt_alloc_table_info()") has unintentionally fortified
xt_alloc_table_info allocation when __GFP_RETRY has been dropped from
the vmalloc fallback. Later on there was a syzbot report that this
can lead to OOM killer invocations when tables are too large and
0537250fdc ("netfilter: x_tables: make allocation less aggressive")
has been merged to restore the original behavior. Georgi Nikolov however
noticed that he is not able to install his iptables anymore so this can
be seen as a regression.

The primary argument for 0537250fdc was that this allocation path
shouldn't really trigger the OOM killer and kill innocent tasks. On the
other hand the interface requires root and as such should allow what the
admin asks for. Root inside a namespaces makes this more complicated
because those might be not trusted in general. If they are not then such
namespaces should be restricted anyway. Therefore drop the __GFP_NORETRY
and replace it by __GFP_ACCOUNT to enfore memcg constrains on it.

Fixes: 0537250fdc ("netfilter: x_tables: make allocation less aggressive")
Reported-by: Georgi Nikolov <gnikolov@icdsoft.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Michal Hocko 2018-08-07 21:54:00 +02:00 committed by Pablo Neira Ayuso
parent 1c117d3b72
commit a148ce1537
1 changed files with 1 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
net/netfilter/x_tables.c
View File

@ -1178,12 +1178,7 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size)
if (sz < sizeof(*info) || sz >= XT_MAX_TABLE_SIZE)
return NULL;
/* __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);
info = kvmalloc(sz, GFP_KERNEL_ACCOUNT);
if (!info)
return NULL;