From 3a3bb480a738afb58aa36d4f5df91282d5712b9e Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Mon, 4 Mar 2019 16:53:46 +0100 Subject: extensions: connlabel: Fallback on missing connlabel.conf If connlabel.conf was not found, fall back to manually parsing arguments as plain numbers. If nfct_labelmap_new() has failed, nfct_labelmap_get_name() segfaults. Therefore make sure it is not called in connlabel_get_name() if that's the case. Signed-off-by: Phil Sutter Signed-off-by: Florian Westphal --- extensions/libxt_connlabel.c | 49 ++++++++++++++++++++++++++++++--------- extensions/libxt_connlabel.t | 23 +++++------------- extensions/libxt_connlabel.txlate | 8 +++---- 3 files changed, 48 insertions(+), 32 deletions(-) (limited to 'extensions') diff --git a/extensions/libxt_connlabel.c b/extensions/libxt_connlabel.c index d06bb27a..5a01fe72 100644 --- a/extensions/libxt_connlabel.c +++ b/extensions/libxt_connlabel.c @@ -1,8 +1,10 @@ +#define _GNU_SOURCE #include #include #include #include #include +#include #include #include #include @@ -32,40 +34,59 @@ static const struct xt_option_entry connlabel_mt_opts[] = { /* cannot do this via _init, else static builds might spew error message * for every iptables invocation. */ -static void connlabel_open(void) +static int connlabel_open(void) { const char *fname; if (map) - return; + return 0; map = nfct_labelmap_new(NULL); if (map != NULL) - return; + return 0; fname = nfct_labels_get_path(); if (errno) { - xtables_error(RESOURCE_PROBLEM, - "cannot open %s: %s", fname, strerror(errno)); + fprintf(stderr, "Warning: cannot open %s: %s\n", + fname, strerror(errno)); } else { xtables_error(RESOURCE_PROBLEM, "cannot parse %s: no labels found", fname); } + return 1; +} + +static int connlabel_value_parse(const char *in) +{ + char *end; + unsigned long value = strtoul(in, &end, 0); + + if (in[0] == '\0' || *end != '\0') + return -1; + + return value; } static void connlabel_mt_parse(struct xt_option_call *cb) { struct xt_connlabel_mtinfo *info = cb->data; + bool have_labelmap = !connlabel_open(); int tmp; - connlabel_open(); xtables_option_parse(cb); switch (cb->entry->id) { case O_LABEL: - tmp = nfct_labelmap_get_bit(map, cb->arg); + if (have_labelmap) + tmp = nfct_labelmap_get_bit(map, cb->arg); + else + tmp = connlabel_value_parse(cb->arg); + if (tmp < 0) - xtables_error(PARAMETER_PROBLEM, "label '%s' not found", cb->arg); + xtables_error(PARAMETER_PROBLEM, + "label '%s' not found or invalid value", + cb->arg); + info->bit = tmp; if (cb->invert) info->options |= XT_CONNLABEL_OP_INVERT; @@ -81,7 +102,8 @@ static const char *connlabel_get_name(int b) { const char *name; - connlabel_open(); + if (connlabel_open()) + return NULL; name = nfct_labelmap_get_name(map, b); if (name && strcmp(name, "")) @@ -134,9 +156,13 @@ static int connlabel_mt_xlate(struct xt_xlate *xl, const struct xt_connlabel_mtinfo *info = (const void *)params->match->data; const char *name = connlabel_get_name(info->bit); + char *valbuf = NULL; - if (name == NULL) - return 0; + if (name == NULL) { + if (asprintf(&valbuf, "%u", info->bit) < 0) + return 0; + name = valbuf; + } if (info->options & XT_CONNLABEL_OP_SET) xt_xlate_add(xl, "ct label set %s ", name); @@ -146,6 +172,7 @@ static int connlabel_mt_xlate(struct xt_xlate *xl, xt_xlate_add(xl, "and %s != ", name); xt_xlate_add(xl, "%s", name); + free(valbuf); return 1; } diff --git a/extensions/libxt_connlabel.t b/extensions/libxt_connlabel.t index aad1032b..7265bd47 100644 --- a/extensions/libxt_connlabel.t +++ b/extensions/libxt_connlabel.t @@ -1,18 +1,7 @@ :INPUT,FORWARD,OUTPUT -# Backup the connlabel.conf, then add some label maps for test -@[ -f /etc/xtables/connlabel.conf ] && mv /etc/xtables/connlabel.conf /tmp/connlabel.conf.bak -@mkdir -p /etc/xtables -@echo "40 bit40" > /etc/xtables/connlabel.conf -@echo "41 bit41" >> /etc/xtables/connlabel.conf -@echo "128 bit128" >> /etc/xtables/connlabel.conf --m connlabel --label "bit40";=;OK --m connlabel ! --label "bit40";=;OK --m connlabel --label "bit41" --set;=;OK --m connlabel ! --label "bit41" --set;=;OK --m connlabel --label "bit128";;FAIL -@echo > /etc/xtables/connlabel.conf --m connlabel --label "abc";;FAIL -@rm -f /etc/xtables/connlabel.conf --m connlabel --label "abc";;FAIL -# Restore the original connlabel.conf -@[ -f /tmp/connlabel.conf.bak ] && mv /tmp/connlabel.conf.bak /etc/xtables/connlabel.conf +-m connlabel --label "40";=;OK +-m connlabel ! --label "40";=;OK +-m connlabel --label "41" --set;=;OK +-m connlabel ! --label "41" --set;=;OK +-m connlabel --label "2048";;FAIL +-m connlabel --label "foobar_not_there";;FAIL diff --git a/extensions/libxt_connlabel.txlate b/extensions/libxt_connlabel.txlate index 5be42204..12e4ac03 100644 --- a/extensions/libxt_connlabel.txlate +++ b/extensions/libxt_connlabel.txlate @@ -1,5 +1,5 @@ -iptables-translate -A INPUT -m connlabel --label bit40 -nft add rule ip filter INPUT ct label bit40 counter +iptables-translate -A INPUT -m connlabel --label 40 +nft add rule ip filter INPUT ct label 40 counter -iptables-translate -A INPUT -m connlabel ! --label bit40 --set -nft add rule ip filter INPUT ct label set bit40 ct label and bit40 != bit40 counter +iptables-translate -A INPUT -m connlabel ! --label 40 --set +nft add rule ip filter INPUT ct label set 40 ct label and 40 != 40 counter -- cgit v1.2.3