syzkaller triggered OOM kills by passing ipt_replace.size = -1 to IPT_SO_SET_REPLACE. The root cause is that SMP_ALIGN() in xt_alloc_table_info() causes int overflow and the size check passes when it should not. SMP_ALIGN() is no longer needed leftover.
Remove SMP_ALIGN() call in xt_alloc_table_info(). Reported-by: [email protected] Signed-off-by: Dmitry Vyukov <[email protected]> Cc: Pablo Neira Ayuso <[email protected]> Cc: Jozsef Kadlecsik <[email protected]> Cc: Florian Westphal <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] --- net/netfilter/x_tables.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 55802e97f906..e02a21549c99 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -39,7 +39,6 @@ MODULE_LICENSE("GPL"); MODULE_AUTHOR("Harald Welte <[email protected]>"); MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module"); -#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) #define XT_PCPU_BLOCK_SIZE 4096 struct compat_delta { @@ -1000,7 +999,7 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size) return NULL; /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */ - if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages) + if ((size >> PAGE_SHIFT) + 2 > totalram_pages) return NULL; info = kvmalloc(sz, GFP_KERNEL); -- 2.15.1.620.gb9897f4670-goog
