[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>
This commit is contained in:
David S. Miller
parent
79030ed07d
commit
9fa492cdc1
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@ -138,12 +138,6 @@ struct xt_counters_info
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#include <linux/netdevice.h>
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#ifdef CONFIG_COMPAT
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#define COMPAT_TO_USER 1
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#define COMPAT_FROM_USER -1
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#define COMPAT_CALC_SIZE 0
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#endif
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struct xt_match
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{
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struct list_head list;
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@ -176,7 +170,8 @@ struct xt_match
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void (*destroy)(const struct xt_match *match, void *matchinfo);
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/* Called when userspace align differs from kernel space one */
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int (*compat)(void *match, void **dstptr, int *size, int convert);
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void (*compat_from_user)(void *dst, void *src);
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int (*compat_to_user)(void __user *dst, void *src);
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/* Set this to THIS_MODULE if you are a module, otherwise NULL */
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struct module *me;
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@ -186,6 +181,7 @@ struct xt_match
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char *table;
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unsigned int matchsize;
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unsigned int compatsize;
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unsigned int hooks;
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unsigned short proto;
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@ -224,13 +220,15 @@ struct xt_target
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void (*destroy)(const struct xt_target *target, void *targinfo);
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/* Called when userspace align differs from kernel space one */
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int (*compat)(void *target, void **dstptr, int *size, int convert);
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void (*compat_from_user)(void *dst, void *src);
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int (*compat_to_user)(void __user *dst, void *src);
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/* Set this to THIS_MODULE if you are a module, otherwise NULL */
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struct module *me;
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char *table;
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unsigned int targetsize;
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unsigned int compatsize;
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unsigned int hooks;
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unsigned short proto;
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@ -387,9 +385,18 @@ struct compat_xt_counters_info
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extern void xt_compat_lock(int af);
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extern void xt_compat_unlock(int af);
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extern int xt_compat_match(void *match, void **dstptr, int *size, int convert);
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extern int xt_compat_target(void *target, void **dstptr, int *size,
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int convert);
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extern int xt_compat_match_offset(struct xt_match *match);
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extern void xt_compat_match_from_user(struct xt_entry_match *m,
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void **dstptr, int *size);
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extern int xt_compat_match_to_user(struct xt_entry_match *m,
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void * __user *dstptr, int *size);
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extern int xt_compat_target_offset(struct xt_target *target);
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extern void xt_compat_target_from_user(struct xt_entry_target *t,
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void **dstptr, int *size);
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extern int xt_compat_target_to_user(struct xt_entry_target *t,
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void * __user *dstptr, int *size);
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#endif /* CONFIG_COMPAT */
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#endif /* __KERNEL__ */
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@ -942,73 +942,28 @@ static short compat_calc_jump(u_int16_t offset)
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return delta;
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}
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struct compat_ipt_standard_target
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static void compat_standard_from_user(void *dst, void *src)
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{
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struct compat_xt_entry_target target;
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compat_int_t verdict;
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};
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int v = *(compat_int_t *)src;
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struct compat_ipt_standard
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if (v > 0)
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v += compat_calc_jump(v);
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memcpy(dst, &v, sizeof(v));
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}
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static int compat_standard_to_user(void __user *dst, void *src)
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{
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struct compat_ipt_entry entry;
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struct compat_ipt_standard_target target;
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};
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compat_int_t cv = *(int *)src;
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#define IPT_ST_LEN XT_ALIGN(sizeof(struct ipt_standard_target))
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#define IPT_ST_COMPAT_LEN COMPAT_XT_ALIGN(sizeof(struct compat_ipt_standard_target))
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#define IPT_ST_OFFSET (IPT_ST_LEN - IPT_ST_COMPAT_LEN)
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static int compat_ipt_standard_fn(void *target,
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void **dstptr, int *size, int convert)
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{
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struct compat_ipt_standard_target compat_st, *pcompat_st;
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struct ipt_standard_target st, *pst;
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int ret;
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ret = 0;
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switch (convert) {
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case COMPAT_TO_USER:
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pst = target;
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memcpy(&compat_st.target, &pst->target,
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sizeof(compat_st.target));
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compat_st.verdict = pst->verdict;
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if (compat_st.verdict > 0)
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compat_st.verdict -=
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compat_calc_jump(compat_st.verdict);
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compat_st.target.u.user.target_size = IPT_ST_COMPAT_LEN;
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if (copy_to_user(*dstptr, &compat_st, IPT_ST_COMPAT_LEN))
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ret = -EFAULT;
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*size -= IPT_ST_OFFSET;
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*dstptr += IPT_ST_COMPAT_LEN;
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break;
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case COMPAT_FROM_USER:
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pcompat_st = target;
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memcpy(&st.target, &pcompat_st->target, IPT_ST_COMPAT_LEN);
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st.verdict = pcompat_st->verdict;
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if (st.verdict > 0)
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st.verdict += compat_calc_jump(st.verdict);
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st.target.u.user.target_size = IPT_ST_LEN;
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memcpy(*dstptr, &st, IPT_ST_LEN);
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*size += IPT_ST_OFFSET;
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*dstptr += IPT_ST_LEN;
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break;
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case COMPAT_CALC_SIZE:
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*size += IPT_ST_OFFSET;
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break;
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default:
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ret = -ENOPROTOOPT;
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break;
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}
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return ret;
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if (cv > 0)
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cv -= compat_calc_jump(cv);
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return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
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}
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static inline int
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compat_calc_match(struct ipt_entry_match *m, int * size)
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{
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if (m->u.kernel.match->compat)
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m->u.kernel.match->compat(m, NULL, size, COMPAT_CALC_SIZE);
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else
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xt_compat_match(m, NULL, size, COMPAT_CALC_SIZE);
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*size += xt_compat_match_offset(m->u.kernel.match);
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return 0;
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}
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@ -1023,10 +978,7 @@ static int compat_calc_entry(struct ipt_entry *e, struct xt_table_info *info,
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entry_offset = (void *)e - base;
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IPT_MATCH_ITERATE(e, compat_calc_match, &off);
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t = ipt_get_target(e);
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if (t->u.kernel.target->compat)
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t->u.kernel.target->compat(t, NULL, &off, COMPAT_CALC_SIZE);
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else
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xt_compat_target(t, NULL, &off, COMPAT_CALC_SIZE);
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off += xt_compat_target_offset(t->u.kernel.target);
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newinfo->size -= off;
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ret = compat_add_offset(entry_offset, off);
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if (ret)
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@ -1412,17 +1364,13 @@ struct compat_ipt_replace {
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};
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static inline int compat_copy_match_to_user(struct ipt_entry_match *m,
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void __user **dstptr, compat_uint_t *size)
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void * __user *dstptr, compat_uint_t *size)
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{
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if (m->u.kernel.match->compat)
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return m->u.kernel.match->compat(m, dstptr, size,
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COMPAT_TO_USER);
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else
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return xt_compat_match(m, dstptr, size, COMPAT_TO_USER);
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return xt_compat_match_to_user(m, dstptr, size);
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}
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static int compat_copy_entry_to_user(struct ipt_entry *e,
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void __user **dstptr, compat_uint_t *size)
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void * __user *dstptr, compat_uint_t *size)
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{
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struct ipt_entry_target __user *t;
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struct compat_ipt_entry __user *ce;
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@ -1442,11 +1390,7 @@ static int compat_copy_entry_to_user(struct ipt_entry *e,
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if (ret)
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goto out;
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t = ipt_get_target(e);
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if (t->u.kernel.target->compat)
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ret = t->u.kernel.target->compat(t, dstptr, size,
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COMPAT_TO_USER);
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else
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ret = xt_compat_target(t, dstptr, size, COMPAT_TO_USER);
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ret = xt_compat_target_to_user(t, dstptr, size);
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if (ret)
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goto out;
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ret = -EFAULT;
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@ -1478,11 +1422,7 @@ compat_check_calc_match(struct ipt_entry_match *m,
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return match ? PTR_ERR(match) : -ENOENT;
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}
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m->u.kernel.match = match;
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if (m->u.kernel.match->compat)
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m->u.kernel.match->compat(m, NULL, size, COMPAT_CALC_SIZE);
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else
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xt_compat_match(m, NULL, size, COMPAT_CALC_SIZE);
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*size += xt_compat_match_offset(match);
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(*i)++;
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return 0;
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@ -1543,10 +1483,7 @@ check_compat_entry_size_and_hooks(struct ipt_entry *e,
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}
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t->u.kernel.target = target;
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if (t->u.kernel.target->compat)
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t->u.kernel.target->compat(t, NULL, &off, COMPAT_CALC_SIZE);
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else
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xt_compat_target(t, NULL, &off, COMPAT_CALC_SIZE);
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off += xt_compat_target_offset(target);
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*size += off;
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ret = compat_add_offset(entry_offset, off);
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if (ret)
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@ -1584,10 +1521,7 @@ static inline int compat_copy_match_from_user(struct ipt_entry_match *m,
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dm = (struct ipt_entry_match *)*dstptr;
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match = m->u.kernel.match;
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if (match->compat)
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match->compat(m, dstptr, size, COMPAT_FROM_USER);
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else
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xt_compat_match(m, dstptr, size, COMPAT_FROM_USER);
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xt_compat_match_from_user(m, dstptr, size);
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ret = xt_check_match(match, AF_INET, dm->u.match_size - sizeof(*dm),
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name, hookmask, ip->proto,
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@ -1635,10 +1569,7 @@ static int compat_copy_entry_from_user(struct ipt_entry *e, void **dstptr,
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de->target_offset = e->target_offset - (origsize - *size);
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t = ipt_get_target(e);
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target = t->u.kernel.target;
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if (target->compat)
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target->compat(t, dstptr, size, COMPAT_FROM_USER);
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else
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xt_compat_target(t, dstptr, size, COMPAT_FROM_USER);
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xt_compat_target_from_user(t, dstptr, size);
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de->next_offset = e->next_offset - (origsize - *size);
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for (h = 0; h < NF_IP_NUMHOOKS; h++) {
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@ -2205,7 +2136,9 @@ static struct ipt_target ipt_standard_target = {
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.targetsize = sizeof(int),
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.family = AF_INET,
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#ifdef CONFIG_COMPAT
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.compat = &compat_ipt_standard_fn,
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.compatsize = sizeof(compat_int_t),
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.compat_from_user = compat_standard_from_user,
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.compat_to_user = compat_standard_to_user,
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#endif
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};
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@ -333,52 +333,65 @@ int xt_check_match(const struct xt_match *match, unsigned short family,
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EXPORT_SYMBOL_GPL(xt_check_match);
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#ifdef CONFIG_COMPAT
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int xt_compat_match(void *match, void **dstptr, int *size, int convert)
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int xt_compat_match_offset(struct xt_match *match)
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{
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struct xt_match *m;
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struct compat_xt_entry_match *pcompat_m;
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struct xt_entry_match *pm;
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u_int16_t msize;
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int off, ret;
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ret = 0;
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m = ((struct xt_entry_match *)match)->u.kernel.match;
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off = XT_ALIGN(m->matchsize) - COMPAT_XT_ALIGN(m->matchsize);
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switch (convert) {
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case COMPAT_TO_USER:
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pm = (struct xt_entry_match *)match;
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msize = pm->u.user.match_size;
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if (copy_to_user(*dstptr, pm, msize)) {
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ret = -EFAULT;
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break;
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}
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msize -= off;
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if (put_user(msize, (u_int16_t *)*dstptr))
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ret = -EFAULT;
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*size -= off;
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*dstptr += msize;
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break;
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case COMPAT_FROM_USER:
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pcompat_m = (struct compat_xt_entry_match *)match;
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pm = (struct xt_entry_match *)*dstptr;
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msize = pcompat_m->u.user.match_size;
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memcpy(pm, pcompat_m, msize);
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msize += off;
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pm->u.user.match_size = msize;
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*size += off;
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*dstptr += msize;
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break;
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case COMPAT_CALC_SIZE:
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*size += off;
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break;
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default:
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ret = -ENOPROTOOPT;
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break;
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}
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return ret;
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u_int16_t csize = match->compatsize ? : match->matchsize;
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return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize);
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}
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EXPORT_SYMBOL_GPL(xt_compat_match);
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#endif
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EXPORT_SYMBOL_GPL(xt_compat_match_offset);
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void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
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int *size)
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{
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struct xt_match *match = m->u.kernel.match;
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struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m;
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int pad, off = xt_compat_match_offset(match);
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u_int16_t msize = cm->u.user.match_size;
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m = *dstptr;
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memcpy(m, cm, sizeof(*cm));
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if (match->compat_from_user)
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match->compat_from_user(m->data, cm->data);
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else
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memcpy(m->data, cm->data, msize - sizeof(*cm));
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pad = XT_ALIGN(match->matchsize) - match->matchsize;
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if (pad > 0)
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memset(m->data + match->matchsize, 0, pad);
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msize += off;
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m->u.user.match_size = msize;
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*size += off;
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*dstptr += msize;
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}
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EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
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int xt_compat_match_to_user(struct xt_entry_match *m, void __user **dstptr,
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int *size)
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{
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struct xt_match *match = m->u.kernel.match;
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struct compat_xt_entry_match __user *cm = *dstptr;
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int off = xt_compat_match_offset(match);
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u_int16_t msize = m->u.user.match_size - off;
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if (copy_to_user(cm, m, sizeof(*cm)) ||
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put_user(msize, &cm->u.user.match_size))
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return -EFAULT;
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if (match->compat_to_user) {
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if (match->compat_to_user((void __user *)cm->data, m->data))
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return -EFAULT;
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} else {
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if (copy_to_user(cm->data, m->data, msize - sizeof(*cm)))
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return -EFAULT;
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}
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*size -= off;
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*dstptr += msize;
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return 0;
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}
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EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
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#endif /* CONFIG_COMPAT */
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int xt_check_target(const struct xt_target *target, unsigned short family,
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unsigned int size, const char *table, unsigned int hook_mask,
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@ -410,51 +423,64 @@ int xt_check_target(const struct xt_target *target, unsigned short family,
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EXPORT_SYMBOL_GPL(xt_check_target);
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#ifdef CONFIG_COMPAT
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int xt_compat_target(void *target, void **dstptr, int *size, int convert)
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int xt_compat_target_offset(struct xt_target *target)
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{
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struct xt_target *t;
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struct compat_xt_entry_target *pcompat;
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struct xt_entry_target *pt;
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u_int16_t tsize;
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int off, ret;
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ret = 0;
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t = ((struct xt_entry_target *)target)->u.kernel.target;
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off = XT_ALIGN(t->targetsize) - COMPAT_XT_ALIGN(t->targetsize);
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switch (convert) {
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case COMPAT_TO_USER:
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pt = (struct xt_entry_target *)target;
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tsize = pt->u.user.target_size;
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if (copy_to_user(*dstptr, pt, tsize)) {
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ret = -EFAULT;
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break;
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}
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tsize -= off;
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if (put_user(tsize, (u_int16_t *)*dstptr))
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ret = -EFAULT;
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*size -= off;
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*dstptr += tsize;
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break;
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case COMPAT_FROM_USER:
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pcompat = (struct compat_xt_entry_target *)target;
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pt = (struct xt_entry_target *)*dstptr;
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tsize = pcompat->u.user.target_size;
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memcpy(pt, pcompat, tsize);
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tsize += off;
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pt->u.user.target_size = tsize;
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*size += off;
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*dstptr += tsize;
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break;
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case COMPAT_CALC_SIZE:
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*size += off;
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break;
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default:
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ret = -ENOPROTOOPT;
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break;
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}
|
||||
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)
|
||||
|
|
|
|||
Reference in New Issue