[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/netfilter/x_tables.c b/net/netfilter/x_tables.c
index be7baf4..58522fc 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -333,52 +333,65 @@
EXPORT_SYMBOL_GPL(xt_check_match);
#ifdef CONFIG_COMPAT
-int xt_compat_match(void *match, void **dstptr, int *size, int convert)
+int xt_compat_match_offset(struct xt_match *match)
{
- struct xt_match *m;
- struct compat_xt_entry_match *pcompat_m;
- struct xt_entry_match *pm;
- u_int16_t msize;
- int off, ret;
-
- ret = 0;
- m = ((struct xt_entry_match *)match)->u.kernel.match;
- off = XT_ALIGN(m->matchsize) - COMPAT_XT_ALIGN(m->matchsize);
- switch (convert) {
- case COMPAT_TO_USER:
- pm = (struct xt_entry_match *)match;
- msize = pm->u.user.match_size;
- if (copy_to_user(*dstptr, pm, msize)) {
- ret = -EFAULT;
- break;
- }
- msize -= off;
- if (put_user(msize, (u_int16_t *)*dstptr))
- ret = -EFAULT;
- *size -= off;
- *dstptr += msize;
- break;
- case COMPAT_FROM_USER:
- pcompat_m = (struct compat_xt_entry_match *)match;
- pm = (struct xt_entry_match *)*dstptr;
- msize = pcompat_m->u.user.match_size;
- memcpy(pm, pcompat_m, msize);
- msize += off;
- pm->u.user.match_size = msize;
- *size += off;
- *dstptr += msize;
- break;
- case COMPAT_CALC_SIZE:
- *size += off;
- break;
- default:
- ret = -ENOPROTOOPT;
- break;
- }
- return ret;
+ u_int16_t csize = match->compatsize ? : match->matchsize;
+ return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize);
}
-EXPORT_SYMBOL_GPL(xt_compat_match);
-#endif
+EXPORT_SYMBOL_GPL(xt_compat_match_offset);
+
+void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
+ int *size)
+{
+ struct xt_match *match = m->u.kernel.match;
+ struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m;
+ int pad, off = xt_compat_match_offset(match);
+ u_int16_t msize = cm->u.user.match_size;
+
+ m = *dstptr;
+ memcpy(m, cm, sizeof(*cm));
+ if (match->compat_from_user)
+ match->compat_from_user(m->data, cm->data);
+ else
+ memcpy(m->data, cm->data, msize - sizeof(*cm));
+ pad = XT_ALIGN(match->matchsize) - match->matchsize;
+ if (pad > 0)
+ memset(m->data + match->matchsize, 0, pad);
+
+ msize += off;
+ m->u.user.match_size = msize;
+
+ *size += off;
+ *dstptr += msize;
+}
+EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
+
+int xt_compat_match_to_user(struct xt_entry_match *m, void __user **dstptr,
+ int *size)
+{
+ struct xt_match *match = m->u.kernel.match;
+ struct compat_xt_entry_match __user *cm = *dstptr;
+ int off = xt_compat_match_offset(match);
+ u_int16_t msize = m->u.user.match_size - off;
+
+ if (copy_to_user(cm, m, sizeof(*cm)) ||
+ put_user(msize, &cm->u.user.match_size))
+ return -EFAULT;
+
+ if (match->compat_to_user) {
+ if (match->compat_to_user((void __user *)cm->data, m->data))
+ return -EFAULT;
+ } else {
+ if (copy_to_user(cm->data, m->data, msize - sizeof(*cm)))
+ return -EFAULT;
+ }
+
+ *size -= off;
+ *dstptr += msize;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
+#endif /* CONFIG_COMPAT */
int xt_check_target(const struct xt_target *target, unsigned short family,
unsigned int size, const char *table, unsigned int hook_mask,
@@ -410,51 +423,64 @@
EXPORT_SYMBOL_GPL(xt_check_target);
#ifdef CONFIG_COMPAT
-int xt_compat_target(void *target, void **dstptr, int *size, int convert)
+int xt_compat_target_offset(struct xt_target *target)
{
- struct xt_target *t;
- struct compat_xt_entry_target *pcompat;
- struct xt_entry_target *pt;
- u_int16_t tsize;
- int off, ret;
-
- ret = 0;
- t = ((struct xt_entry_target *)target)->u.kernel.target;
- off = XT_ALIGN(t->targetsize) - COMPAT_XT_ALIGN(t->targetsize);
- switch (convert) {
- case COMPAT_TO_USER:
- pt = (struct xt_entry_target *)target;
- tsize = pt->u.user.target_size;
- if (copy_to_user(*dstptr, pt, tsize)) {
- ret = -EFAULT;
- break;
- }
- tsize -= off;
- if (put_user(tsize, (u_int16_t *)*dstptr))
- ret = -EFAULT;
- *size -= off;
- *dstptr += tsize;
- break;
- case COMPAT_FROM_USER:
- pcompat = (struct compat_xt_entry_target *)target;
- pt = (struct xt_entry_target *)*dstptr;
- tsize = pcompat->u.user.target_size;
- memcpy(pt, pcompat, tsize);
- tsize += off;
- pt->u.user.target_size = tsize;
- *size += off;
- *dstptr += tsize;
- break;
- case COMPAT_CALC_SIZE:
- *size += off;
- break;
- default:
- ret = -ENOPROTOOPT;
- break;
- }
- return ret;
+ u_int16_t csize = target->compatsize ? : target->targetsize;
+ return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize);
}
-EXPORT_SYMBOL_GPL(xt_compat_target);
+EXPORT_SYMBOL_GPL(xt_compat_target_offset);
+
+void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
+ int *size)
+{
+ struct xt_target *target = t->u.kernel.target;
+ struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t;
+ int pad, off = xt_compat_target_offset(target);
+ u_int16_t tsize = ct->u.user.target_size;
+
+ t = *dstptr;
+ memcpy(t, ct, sizeof(*ct));
+ if (target->compat_from_user)
+ target->compat_from_user(t->data, ct->data);
+ else
+ memcpy(t->data, ct->data, tsize - sizeof(*ct));
+ pad = XT_ALIGN(target->targetsize) - target->targetsize;
+ if (pad > 0)
+ memset(t->data + target->targetsize, 0, pad);
+
+ tsize += off;
+ t->u.user.target_size = tsize;
+
+ *size += off;
+ *dstptr += tsize;
+}
+EXPORT_SYMBOL_GPL(xt_compat_target_from_user);
+
+int xt_compat_target_to_user(struct xt_entry_target *t, void __user **dstptr,
+ int *size)
+{
+ struct xt_target *target = t->u.kernel.target;
+ struct compat_xt_entry_target __user *ct = *dstptr;
+ int off = xt_compat_target_offset(target);
+ u_int16_t tsize = t->u.user.target_size - off;
+
+ if (copy_to_user(ct, t, sizeof(*ct)) ||
+ put_user(tsize, &ct->u.user.target_size))
+ return -EFAULT;
+
+ if (target->compat_to_user) {
+ if (target->compat_to_user((void __user *)ct->data, t->data))
+ return -EFAULT;
+ } else {
+ if (copy_to_user(ct->data, t->data, tsize - sizeof(*ct)))
+ return -EFAULT;
+ }
+
+ *size -= off;
+ *dstptr += tsize;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xt_compat_target_to_user);
#endif
struct xt_table_info *xt_alloc_table_info(unsigned int size)
