[NETFILTER]: x_tables: simplify compat API
Split the xt_compat_match/xt_compat_target into smaller type-safe functions
performing just one operation. Handle all alignment and size-related
conversions centrally in these function instead of requiring each module to
implement a full-blown conversion function. Replace ->compat callback by
->compat_from_user and ->compat_to_user callbacks, responsible for
converting just a single private structure.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 673581d..800067d 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -942,73 +942,28 @@
return delta;
}
-struct compat_ipt_standard_target
+static void compat_standard_from_user(void *dst, void *src)
{
- struct compat_xt_entry_target target;
- compat_int_t verdict;
-};
+ int v = *(compat_int_t *)src;
-struct compat_ipt_standard
+ if (v > 0)
+ v += compat_calc_jump(v);
+ memcpy(dst, &v, sizeof(v));
+}
+
+static int compat_standard_to_user(void __user *dst, void *src)
{
- struct compat_ipt_entry entry;
- struct compat_ipt_standard_target target;
-};
+ compat_int_t cv = *(int *)src;
-#define IPT_ST_LEN XT_ALIGN(sizeof(struct ipt_standard_target))
-#define IPT_ST_COMPAT_LEN COMPAT_XT_ALIGN(sizeof(struct compat_ipt_standard_target))
-#define IPT_ST_OFFSET (IPT_ST_LEN - IPT_ST_COMPAT_LEN)
-
-static int compat_ipt_standard_fn(void *target,
- void **dstptr, int *size, int convert)
-{
- struct compat_ipt_standard_target compat_st, *pcompat_st;
- struct ipt_standard_target st, *pst;
- int ret;
-
- ret = 0;
- switch (convert) {
- case COMPAT_TO_USER:
- pst = target;
- memcpy(&compat_st.target, &pst->target,
- sizeof(compat_st.target));
- compat_st.verdict = pst->verdict;
- if (compat_st.verdict > 0)
- compat_st.verdict -=
- compat_calc_jump(compat_st.verdict);
- compat_st.target.u.user.target_size = IPT_ST_COMPAT_LEN;
- if (copy_to_user(*dstptr, &compat_st, IPT_ST_COMPAT_LEN))
- ret = -EFAULT;
- *size -= IPT_ST_OFFSET;
- *dstptr += IPT_ST_COMPAT_LEN;
- break;
- case COMPAT_FROM_USER:
- pcompat_st = target;
- memcpy(&st.target, &pcompat_st->target, IPT_ST_COMPAT_LEN);
- st.verdict = pcompat_st->verdict;
- if (st.verdict > 0)
- st.verdict += compat_calc_jump(st.verdict);
- st.target.u.user.target_size = IPT_ST_LEN;
- memcpy(*dstptr, &st, IPT_ST_LEN);
- *size += IPT_ST_OFFSET;
- *dstptr += IPT_ST_LEN;
- break;
- case COMPAT_CALC_SIZE:
- *size += IPT_ST_OFFSET;
- break;
- default:
- ret = -ENOPROTOOPT;
- break;
- }
- return ret;
+ if (cv > 0)
+ cv -= compat_calc_jump(cv);
+ return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
}
static inline int
compat_calc_match(struct ipt_entry_match *m, int * size)
{
- if (m->u.kernel.match->compat)
- m->u.kernel.match->compat(m, NULL, size, COMPAT_CALC_SIZE);
- else
- xt_compat_match(m, NULL, size, COMPAT_CALC_SIZE);
+ *size += xt_compat_match_offset(m->u.kernel.match);
return 0;
}
@@ -1023,10 +978,7 @@
entry_offset = (void *)e - base;
IPT_MATCH_ITERATE(e, compat_calc_match, &off);
t = ipt_get_target(e);
- if (t->u.kernel.target->compat)
- t->u.kernel.target->compat(t, NULL, &off, COMPAT_CALC_SIZE);
- else
- xt_compat_target(t, NULL, &off, COMPAT_CALC_SIZE);
+ off += xt_compat_target_offset(t->u.kernel.target);
newinfo->size -= off;
ret = compat_add_offset(entry_offset, off);
if (ret)
@@ -1412,17 +1364,13 @@
};
static inline int compat_copy_match_to_user(struct ipt_entry_match *m,
- void __user **dstptr, compat_uint_t *size)
+ void * __user *dstptr, compat_uint_t *size)
{
- if (m->u.kernel.match->compat)
- return m->u.kernel.match->compat(m, dstptr, size,
- COMPAT_TO_USER);
- else
- return xt_compat_match(m, dstptr, size, COMPAT_TO_USER);
+ return xt_compat_match_to_user(m, dstptr, size);
}
static int compat_copy_entry_to_user(struct ipt_entry *e,
- void __user **dstptr, compat_uint_t *size)
+ void * __user *dstptr, compat_uint_t *size)
{
struct ipt_entry_target __user *t;
struct compat_ipt_entry __user *ce;
@@ -1442,11 +1390,7 @@
if (ret)
goto out;
t = ipt_get_target(e);
- if (t->u.kernel.target->compat)
- ret = t->u.kernel.target->compat(t, dstptr, size,
- COMPAT_TO_USER);
- else
- ret = xt_compat_target(t, dstptr, size, COMPAT_TO_USER);
+ ret = xt_compat_target_to_user(t, dstptr, size);
if (ret)
goto out;
ret = -EFAULT;
@@ -1478,11 +1422,7 @@
return match ? PTR_ERR(match) : -ENOENT;
}
m->u.kernel.match = match;
-
- if (m->u.kernel.match->compat)
- m->u.kernel.match->compat(m, NULL, size, COMPAT_CALC_SIZE);
- else
- xt_compat_match(m, NULL, size, COMPAT_CALC_SIZE);
+ *size += xt_compat_match_offset(match);
(*i)++;
return 0;
@@ -1543,10 +1483,7 @@
}
t->u.kernel.target = target;
- if (t->u.kernel.target->compat)
- t->u.kernel.target->compat(t, NULL, &off, COMPAT_CALC_SIZE);
- else
- xt_compat_target(t, NULL, &off, COMPAT_CALC_SIZE);
+ off += xt_compat_target_offset(target);
*size += off;
ret = compat_add_offset(entry_offset, off);
if (ret)
@@ -1584,10 +1521,7 @@
dm = (struct ipt_entry_match *)*dstptr;
match = m->u.kernel.match;
- if (match->compat)
- match->compat(m, dstptr, size, COMPAT_FROM_USER);
- else
- xt_compat_match(m, dstptr, size, COMPAT_FROM_USER);
+ xt_compat_match_from_user(m, dstptr, size);
ret = xt_check_match(match, AF_INET, dm->u.match_size - sizeof(*dm),
name, hookmask, ip->proto,
@@ -1635,10 +1569,7 @@
de->target_offset = e->target_offset - (origsize - *size);
t = ipt_get_target(e);
target = t->u.kernel.target;
- if (target->compat)
- target->compat(t, dstptr, size, COMPAT_FROM_USER);
- else
- xt_compat_target(t, dstptr, size, COMPAT_FROM_USER);
+ xt_compat_target_from_user(t, dstptr, size);
de->next_offset = e->next_offset - (origsize - *size);
for (h = 0; h < NF_IP_NUMHOOKS; h++) {
@@ -2205,7 +2136,9 @@
.targetsize = sizeof(int),
.family = AF_INET,
#ifdef CONFIG_COMPAT
- .compat = &compat_ipt_standard_fn,
+ .compatsize = sizeof(compat_int_t),
+ .compat_from_user = compat_standard_from_user,
+ .compat_to_user = compat_standard_to_user,
#endif
};