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netfilter: compat: reject huge allocation requests 

no need to bother even trying to allocating huge compat offset arrays,
such ruleset is rejected later on anyway becaus we refuse to allocate
overly large rule blobs.

However, compat translation happens before blob allocation, so we should
add a check there too.

This is supposed to help with fuzzing by avoiding oom-killer.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
zero-colors
Florian Westphal 2018-02-27 19:42:35 +01:00 committed by Pablo Neira Ayuso
parent 9782a11efc
commit 7d7d7e0211
1 changed files with 18 additions and 8 deletions
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26
net/netfilter/x_tables.c
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@ -582,14 +582,8 @@ int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta)
{
struct xt_af *xp = &xt[af];
if (!xp->compat_tab) {
if (!xp->number)
return -EINVAL;
xp->compat_tab = vmalloc(sizeof(struct compat_delta) * xp->number);
if (!xp->compat_tab)
return -ENOMEM;
xp->cur = 0;
}
if (WARN_ON(!xp->compat_tab))
return -ENOMEM;
if (xp->cur >= xp->number)
return -EINVAL;
@ -634,6 +628,22 @@ EXPORT_SYMBOL_GPL(xt_compat_calc_jump);
int xt_compat_init_offsets(u8 af, unsigned int number)
{
size_t mem;
if (!number || number > (INT_MAX / sizeof(struct compat_delta)))
return -EINVAL;
if (WARN_ON(xt[af].compat_tab))
return -EINVAL;
mem = sizeof(struct compat_delta) * number;
if (mem > XT_MAX_TABLE_SIZE)
return -ENOMEM;
xt[af].compat_tab = vmalloc(mem);
if (!xt[af].compat_tab)
return -ENOMEM;
xt[af].number = number;
xt[af].cur = 0;