diff options
| author | Florian Westphal <fw@strlen.de> | 2018-03-10 01:15:45 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-08 11:51:59 +0200 |
| commit | 9aaaa409c5c3b985fce81a6dfd662d60b2fc1ee5 (patch) | |
| tree | ae00204075d7914bd76c868f5221b70f8d89bdff /net/netfilter | |
| parent | eaa0e4e1b93e4e16fa771cb8ca1eaa0b47a30452 (diff) | |
netfilter: x_tables: add and use xt_check_proc_name
commit b1d0a5d0cba4597c0394997b2d5fced3e3841b4e upstream.
recent and hashlimit both create /proc files, but only check that
name is 0 terminated.
This can trigger WARN() from procfs when name is "" or "/".
Add helper for this and then use it for both.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: <syzbot+0502b00edac2a0680b61@syzkaller.appspotmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/netfilter')
| -rw-r--r-- | net/netfilter/x_tables.c | 30 | ||||
| -rw-r--r-- | net/netfilter/xt_hashlimit.c | 5 | ||||
| -rw-r--r-- | net/netfilter/xt_recent.c | 6 |
3 files changed, 36 insertions, 5 deletions
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 34ae20490c94..1f3c305df45d 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -366,6 +366,36 @@ textify_hooks(char *buf, size_t size, unsigned int mask, uint8_t nfproto) return buf; } +/** + * xt_check_proc_name - check that name is suitable for /proc file creation + * + * @name: file name candidate + * @size: length of buffer + * + * some x_tables modules wish to create a file in /proc. + * This function makes sure that the name is suitable for this + * purpose, it checks that name is NUL terminated and isn't a 'special' + * name, like "..". + * + * returns negative number on error or 0 if name is useable. + */ +int xt_check_proc_name(const char *name, unsigned int size) +{ + if (name[0] == '\0') + return -EINVAL; + + if (strnlen(name, size) == size) + return -ENAMETOOLONG; + + if (strcmp(name, ".") == 0 || + strcmp(name, "..") == 0 || + strchr(name, '/')) + return -EINVAL; + + return 0; +} +EXPORT_SYMBOL(xt_check_proc_name); + int xt_check_match(struct xt_mtchk_param *par, unsigned int size, u_int8_t proto, bool inv_proto) { diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index 178696852bde..7381be0cdcdf 100644 --- a/net/netfilter/xt_hashlimit.c +++ b/net/netfilter/xt_hashlimit.c @@ -668,8 +668,9 @@ static int hashlimit_mt_check(const struct xt_mtchk_param *par) if (info->cfg.gc_interval == 0 || info->cfg.expire == 0) return -EINVAL; - if (info->name[sizeof(info->name)-1] != '\0') - return -EINVAL; + ret = xt_check_proc_name(info->name, sizeof(info->name)); + if (ret) + return ret; if (par->family == NFPROTO_IPV4) { if (info->cfg.srcmask > 32 || info->cfg.dstmask > 32) return -EINVAL; diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c index d725a27743a1..cd53b861a15c 100644 --- a/net/netfilter/xt_recent.c +++ b/net/netfilter/xt_recent.c @@ -364,9 +364,9 @@ static int recent_mt_check(const struct xt_mtchk_param *par, info->hit_count, XT_RECENT_MAX_NSTAMPS - 1); return -EINVAL; } - if (info->name[0] == '\0' || - strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN) - return -EINVAL; + ret = xt_check_proc_name(info->name, sizeof(info->name)); + if (ret) + return ret; if (ip_pkt_list_tot && info->hit_count < ip_pkt_list_tot) nstamp_mask = roundup_pow_of_two(ip_pkt_list_tot) - 1; |