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Commit 848edc69 authored by Santosh Nayak's avatar Santosh Nayak Committed by David S. Miller
Browse files

netfilter: ebtables: fix wrong name length while copying to user-space 



user-space ebtables expects 32 bytes-long names, but xt_match names
use 29 bytes. We have to copy less 29 bytes and then, make sure we
fill the remaining bytes with zeroes.

Signed-off-by: default avatarSantosh Nayak <santoshprasadnayak@gmail.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2a15cd2f

net/bridge/netfilter/ebtables.c

+13 −3
Original line number Diff line number Diff line
@@ -1335,7 +1335,12 @@ static inline int ebt_make_matchname(const struct ebt_entry_match *m, 
    const char *base, char __user *ubase)

{

	char __user *hlp = ubase + ((char *)m - base);

	if (copy_to_user(hlp, m->u.match->name, EBT_FUNCTION_MAXNAMELEN))

	char name[EBT_FUNCTION_MAXNAMELEN] = {};



	/* ebtables expects 32 bytes long names but xt_match names are 29 bytes

	   long. Copy 29 bytes and fill remaining bytes with zeroes. */

	strncpy(name, m->u.match->name, sizeof(name));

	if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))

		return -EFAULT;

	return 0;

}
@@ -1344,7 +1349,10 @@ static inline int ebt_make_watchername(const struct ebt_entry_watcher *w, 
    const char *base, char __user *ubase)

{

	char __user *hlp = ubase + ((char *)w - base);

	if (copy_to_user(hlp , w->u.watcher->name, EBT_FUNCTION_MAXNAMELEN))

	char name[EBT_FUNCTION_MAXNAMELEN] = {};



	strncpy(name, w->u.watcher->name, sizeof(name));

	if (copy_to_user(hlp , name, EBT_FUNCTION_MAXNAMELEN))

		return -EFAULT;

	return 0;

}
@@ -1355,10 +1363,12 @@ ebt_make_names(struct ebt_entry *e, const char *base, char __user *ubase) 
	int ret;

	char __user *hlp;

	const struct ebt_entry_target *t;

	char name[EBT_FUNCTION_MAXNAMELEN] = {};



	if (e->bitmask == 0)

		return 0;



	strncpy(name, t->u.target->name, sizeof(name));

	hlp = ubase + (((char *)e + e->target_offset) - base);

	t = (struct ebt_entry_target *)(((char *)e) + e->target_offset);
@@ -1368,7 +1378,7 @@ ebt_make_names(struct ebt_entry *e, const char *base, char __user *ubase) 
	ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase);

	if (ret != 0)

		return ret;

	if (copy_to_user(hlp, t->u.target->name, EBT_FUNCTION_MAXNAMELEN))

	if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN))

		return -EFAULT;

	return 0;

}