From b5040f6c33a51e6e1fddab75baf0f45d4943cde4 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 2 Jan 2017 17:19:44 -0500 Subject: ebtables: use match, target and data copy_to_user helpers Convert ebtables to copying entries, matches and targets one by one. The solution is analogous to that of generic xt_(match|target)_to_user helpers, but is applied to different structs. Convert existing helpers ebt_make_XXXname helpers that overwrite fields of an already copy_to_user'd struct with ebt_XXX_to_user helpers that copy all relevant fields of the struct from scratch. Signed-off-by: Willem de Bruijn Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/ebtables.c | 78 +++++++++++++++++++++++++---------------- 1 file changed, 47 insertions(+), 31 deletions(-) (limited to 'net/bridge/netfilter') diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index 537e3d506fc2..79b69917f521 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1346,56 +1346,72 @@ static int update_counters(struct net *net, const void __user *user, hlp.num_counters, user, len); } -static inline int ebt_make_matchname(const struct ebt_entry_match *m, - const char *base, char __user *ubase) +static inline int ebt_obj_to_user(char __user *um, const char *_name, + const char *data, int entrysize, + int usersize, int datasize) { - char __user *hlp = ubase + ((char *)m - base); - char name[EBT_FUNCTION_MAXNAMELEN] = {}; + char name[EBT_FUNCTION_MAXNAMELEN] = {0}; /* ebtables expects 32 bytes long names but xt_match names are 29 bytes * long. Copy 29 bytes and fill remaining bytes with zeroes. */ - strlcpy(name, m->u.match->name, sizeof(name)); - if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN)) + strlcpy(name, _name, sizeof(name)); + if (copy_to_user(um, name, EBT_FUNCTION_MAXNAMELEN) || + put_user(datasize, (int __user *)(um + EBT_FUNCTION_MAXNAMELEN)) || + xt_data_to_user(um + entrysize, data, usersize, datasize)) return -EFAULT; + return 0; } -static inline int ebt_make_watchername(const struct ebt_entry_watcher *w, - const char *base, char __user *ubase) +static inline int ebt_match_to_user(const struct ebt_entry_match *m, + const char *base, char __user *ubase) { - char __user *hlp = ubase + ((char *)w - base); - char name[EBT_FUNCTION_MAXNAMELEN] = {}; + return ebt_obj_to_user(ubase + ((char *)m - base), + m->u.match->name, m->data, sizeof(*m), + m->u.match->usersize, m->match_size); +} - strlcpy(name, w->u.watcher->name, sizeof(name)); - if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN)) - return -EFAULT; - return 0; +static inline int ebt_watcher_to_user(const struct ebt_entry_watcher *w, + const char *base, char __user *ubase) +{ + return ebt_obj_to_user(ubase + ((char *)w - base), + w->u.watcher->name, w->data, sizeof(*w), + w->u.watcher->usersize, w->watcher_size); } -static inline int ebt_make_names(struct ebt_entry *e, const char *base, - char __user *ubase) +static inline int ebt_entry_to_user(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) + if (e->bitmask == 0) { + /* special case !EBT_ENTRY_OR_ENTRIES */ + if (copy_to_user(ubase + ((char *)e - base), e, + sizeof(struct ebt_entries))) + return -EFAULT; return 0; + } + + if (copy_to_user(ubase + ((char *)e - base), e, sizeof(*e))) + return -EFAULT; hlp = ubase + (((char *)e + e->target_offset) - base); t = (struct ebt_entry_target *)(((char *)e) + e->target_offset); - ret = EBT_MATCH_ITERATE(e, ebt_make_matchname, base, ubase); + ret = EBT_MATCH_ITERATE(e, ebt_match_to_user, base, ubase); if (ret != 0) return ret; - ret = EBT_WATCHER_ITERATE(e, ebt_make_watchername, base, ubase); + ret = EBT_WATCHER_ITERATE(e, ebt_watcher_to_user, base, ubase); if (ret != 0) return ret; - strlcpy(name, t->u.target->name, sizeof(name)); - if (copy_to_user(hlp, name, EBT_FUNCTION_MAXNAMELEN)) - return -EFAULT; + ret = ebt_obj_to_user(hlp, t->u.target->name, t->data, sizeof(*t), + t->u.target->usersize, t->target_size); + if (ret != 0) + return ret; + return 0; } @@ -1475,13 +1491,9 @@ static int copy_everything_to_user(struct ebt_table *t, void __user *user, if (ret) return ret; - if (copy_to_user(tmp.entries, entries, entries_size)) { - BUGPRINT("Couldn't copy entries to userspace\n"); - return -EFAULT; - } /* set the match/watcher/target names right */ return EBT_ENTRY_ITERATE(entries, entries_size, - ebt_make_names, entries, tmp.entries); + ebt_entry_to_user, entries, tmp.entries); } static int do_ebt_set_ctl(struct sock *sk, @@ -1630,8 +1642,10 @@ static int compat_match_to_user(struct ebt_entry_match *m, void __user **dstptr, if (match->compat_to_user) { if (match->compat_to_user(cm->data, m->data)) return -EFAULT; - } else if (copy_to_user(cm->data, m->data, msize)) + } else { + if (xt_data_to_user(cm->data, m->data, match->usersize, msize)) return -EFAULT; + } *size -= ebt_compat_entry_padsize() + off; *dstptr = cm->data; @@ -1657,8 +1671,10 @@ static int compat_target_to_user(struct ebt_entry_target *t, if (target->compat_to_user) { if (target->compat_to_user(cm->data, t->data)) return -EFAULT; - } else if (copy_to_user(cm->data, t->data, tsize)) - return -EFAULT; + } else { + if (xt_data_to_user(cm->data, t->data, target->usersize, tsize)) + return -EFAULT; + } *size -= ebt_compat_entry_padsize() + off; *dstptr = cm->data; -- cgit