diff options
| author | Florian Westphal <fw@strlen.de> | 2021-04-07 21:38:57 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2021-04-13 00:18:57 +0200 |
| commit | b29c457a6511435960115c0f548c4360d5f4801d (patch) | |
| tree | a2cabc721228fc1d876374aac3bd7758d4016165 /net/netfilter | |
| parent | d163a925ebbc6eb5b562b0f1d72c7e817aa75c40 (diff) | |
netfilter: x_tables: fix compat match/target pad out-of-bound write
xt_compat_match/target_from_user doesn't check that zeroing the area
to start of next rule won't write past end of allocated ruleset blob.
Remove this code and zero the entire blob beforehand.
Reported-by: syzbot+cfc0247ac173f597aaaa@syzkaller.appspotmail.com
Reported-by: Andy Nguyen <theflow@google.com>
Fixes: 9fa492cdc160c ("[NETFILTER]: x_tables: simplify compat API")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/x_tables.c | 10 |
1 files changed, 2 insertions, 8 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 6bd31a7a27fc..92e9d4ebc5e8 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -733,7 +733,7 @@ void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, { const 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); + int off = xt_compat_match_offset(match); u_int16_t msize = cm->u.user.match_size; char name[sizeof(m->u.user.name)]; @@ -743,9 +743,6 @@ void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, 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; @@ -1116,7 +1113,7 @@ void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, { const 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); + int off = xt_compat_target_offset(target); u_int16_t tsize = ct->u.user.target_size; char name[sizeof(t->u.user.name)]; @@ -1126,9 +1123,6 @@ void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 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; |