diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-10-05 02:50:07 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-19 22:47:16 +0200 |
| commit | 3ea051bcf2cd0860c97c7133e1a20923be7529fb (patch) | |
| tree | 2d57edb7ecaebe3ed34f66499ccb9346a057a6a6 | |
| parent | 2679c2231bc3fb260f74e1faf7d6810427b1fc6e (diff) | |
netfilter: x_tables: avoid stack-out-of-bounds read in xt_copy_counters_from_user
commit e466af75c074e76107ae1cd5a2823e9c61894ffb upstream.
syzkaller reports an out of bound read in strlcpy(), triggered
by xt_copy_counters_from_user()
Fix this by using memcpy(), then forcing a zero byte at the last position
of the destination, as Florian did for the non COMPAT code.
Fixes: d7591f0c41ce ("netfilter: x_tables: introduce and use xt_copy_counters_from_user")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/netfilter/x_tables.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 59be89813a29..751fec729ffb 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -877,7 +877,7 @@ void *xt_copy_counters_from_user(const void __user *user, unsigned int len, if (copy_from_user(&compat_tmp, user, sizeof(compat_tmp)) != 0) return ERR_PTR(-EFAULT); - strlcpy(info->name, compat_tmp.name, sizeof(info->name)); + memcpy(info->name, compat_tmp.name, sizeof(info->name) - 1); info->num_counters = compat_tmp.num_counters; user += sizeof(compat_tmp); } else @@ -890,9 +890,9 @@ void *xt_copy_counters_from_user(const void __user *user, unsigned int len, if (copy_from_user(info, user, sizeof(*info)) != 0) return ERR_PTR(-EFAULT); - info->name[sizeof(info->name) - 1] = '\0'; user += sizeof(*info); } + info->name[sizeof(info->name) - 1] = '\0'; size = sizeof(struct xt_counters); size *= info->num_counters; |