From ea7c73a76f63a88a34bc06649f3d7f934fd0a18f Mon Sep 17 00:00:00 2001 From: Stefan Berger Date: Fri, 18 Nov 2011 11:58:18 -0500 Subject: [PATCH] Enable chains with names having a known prefix This patch enables chains that have a known prefix in their name. Known prefixes are: 'ipv4', 'ipv6', 'arp', 'rarp'. All prefixes are also protocols that can be evaluated on the ebtables level. Following the prefix they will be automatically connected to an interface's 'root' chain and jumped into following the protocol they evaluate, i.e., a table 'arp-xyz' will be accessed from the root table using ebtables -t nat -A -p arp -j I--arp-xyz thus generating a 'root' chain like this one here: Bridge chain: libvirt-O-vnet0, entries: 5, policy: ACCEPT -p IPv4 -j O-vnet0-ipv4 -p ARP -j O-vnet0-arp -p 0x8035 -j O-vnet0-rarp -p ARP -j O-vnet0-arp-xyz -j DROP where the chain 'arp-xyz' is accessed for filtering of ARP packets. Signed-off-by: Stefan Berger --- docs/schemas/nwfilter.rng | 16 +++++-- src/conf/nwfilter_conf.c | 89 ++++++++++++++++++++++++++++++++++++--- src/conf/nwfilter_conf.h | 3 ++ 3 files changed, 99 insertions(+), 9 deletions(-) diff --git a/docs/schemas/nwfilter.rng b/docs/schemas/nwfilter.rng index e679766323..b9d72760af 100644 --- a/docs/schemas/nwfilter.rng +++ b/docs/schemas/nwfilter.rng @@ -286,10 +286,18 @@ root - arp - rarp - ipv4 - ipv6 + + arp[a-zA-Z0-9_\.:-]{0,9} + + + rarp[a-zA-Z0-9_\.:-]{0,8} + + + ipv4[a-zA-Z0-9_\.:-]{0,8} + + + ipv6[a-zA-Z0-9_\.:-]{0,8} + diff --git a/src/conf/nwfilter_conf.c b/src/conf/nwfilter_conf.c index 4b7c823070..ea9111deeb 100644 --- a/src/conf/nwfilter_conf.c +++ b/src/conf/nwfilter_conf.c @@ -2007,6 +2007,84 @@ err_exit: goto cleanup; } +static bool +virNWFilterIsValidChainName(const char *chainname) +{ + if (strlen(chainname) > MAX_CHAIN_SUFFIX_SIZE) { + virNWFilterReportError(VIR_ERR_INVALID_ARG, + _("Name of chain is longer than " + "%u characters"), + MAX_CHAIN_SUFFIX_SIZE); + return false; + } + + if (chainname[strspn(chainname, VALID_CHAINNAME)] != 0) { + virNWFilterReportError(VIR_ERR_INVALID_ARG, + _("Chain name contains invalid characters")); + return false; + } + + return true; +} + +/* + * Test whether the name of the chain is supported. + * It current has to have a prefix of either one of the strings found in + * virNWFilterChainSuffixTypeToString(). + */ +static const char * +virNWFilterIsAllowedChain(const char *chainname) +{ + enum virNWFilterChainSuffixType i; + const char *name, *msg; + virBuffer buf = VIR_BUFFER_INITIALIZER; + bool printed = false; + + if (!virNWFilterIsValidChainName(chainname)) + return NULL; + + for (i = 0; i < VIR_NWFILTER_CHAINSUFFIX_LAST; i++) { + name = virNWFilterChainSuffixTypeToString(i); + if (i == VIR_NWFILTER_CHAINSUFFIX_ROOT) { + /* allow 'root' as a complete name but not as a prefix */ + if (STREQ(chainname, name)) + return name; + if (STRPREFIX(chainname, name)) + return NULL; + } + if (STRPREFIX(chainname, name)) + return name; + } + + virBufferAsprintf(&buf, + _("Invalid chain name '%s'. Please use a chain name " + "called '%s' or any of the following prefixes: "), + chainname, + virNWFilterChainSuffixTypeToString( + VIR_NWFILTER_CHAINSUFFIX_ROOT)); + for (i = 0; i < VIR_NWFILTER_CHAINSUFFIX_LAST; i++) { + if (i == VIR_NWFILTER_CHAINSUFFIX_ROOT) + continue; + if (printed) + virBufferAddLit(&buf, ", "); + virBufferAdd(&buf, virNWFilterChainSuffixTypeToString(i), -1); + printed = true; + } + + if (virBufferError(&buf)) { + virReportOOMError(); + virBufferFreeAndReset(&buf); + goto err_exit; + } + + msg = virBufferContentAndReset(&buf); + + virNWFilterReportError(VIR_ERR_INVALID_ARG, "%s", msg); + VIR_FREE(msg); + +err_exit: + return NULL; +} static virNWFilterDefPtr virNWFilterDefParseXML(xmlXPathContextPtr ctxt) { @@ -2017,6 +2095,7 @@ virNWFilterDefParseXML(xmlXPathContextPtr ctxt) { char *chain_pri_s = NULL; virNWFilterEntryPtr entry; int chain_priority; + const char *name_prefix; if (VIR_ALLOC(ret) < 0) { virReportOOMError(); @@ -2052,19 +2131,19 @@ virNWFilterDefParseXML(xmlXPathContextPtr ctxt) { chain = virXPathString("string(./@chain)", ctxt); if (chain) { - if (virNWFilterChainSuffixTypeFromString(chain) < 0) { - virNWFilterReportError(VIR_ERR_INTERNAL_ERROR, - _("unknown chain suffix '%s'"), chain); + name_prefix = virNWFilterIsAllowedChain(chain); + if (name_prefix == NULL) goto cleanup; - } ret->chainsuffix = chain; if (chain_pri_s) { ret->chainPriority = chain_priority; } else { /* assign default priority if none can be found via lookup */ - if (!intMapGetByString(chain_priorities, chain, 0, + if (!name_prefix || + !intMapGetByString(chain_priorities, name_prefix, 0, &ret->chainPriority)) { + /* assign default chain priority */ ret->chainPriority = (NWFILTER_MAX_FILTER_PRIORITY + NWFILTER_MIN_FILTER_PRIORITY) / 2; } diff --git a/src/conf/nwfilter_conf.h b/src/conf/nwfilter_conf.h index 0ff14d143a..55b2aad35a 100644 --- a/src/conf/nwfilter_conf.h +++ b/src/conf/nwfilter_conf.h @@ -446,6 +446,9 @@ enum virNWFilterChainSuffixType { VIR_NWFILTER_CHAINSUFFIX_LAST, }; +# define VALID_CHAINNAME \ + "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_.:-" + typedef int32_t virNWFilterChainPriority; typedef struct _virNWFilterDef virNWFilterDef; -- 2.39.5