This gives dnsmasq the ability to originate retries for upstream DNS
queries itself, rather than relying on the downstream client. This is
most useful when doing DNSSEC over unreliable upstream network. It
comes with some cost in memory usage and network bandwidth.
By default, when sending a query via random ports to multiple upstream servers or
retrying a query dnsmasq will use a single random port for all the tries/retries.
This option allows a larger number of ports to be used, which can increase robustness
in certain network configurations. Note that increasing this to more than
two or three can have security and resource implications and should only
be done with understanding of those.
This change also removes a previous bug
where --dhcp-alternate-port would affect the port used
to relay _to_ as well as the port being listened on.
The new feature allows configuration to provide bug-for-bug
compatibility, if required. Thanks to Damian Kaczkowski
for the feature suggestion.
This allows hosts get a domain which relects the interface they
are attached to in a way which doesn't require hard-coding addresses.
Thanks to Sten Spans for the idea.
Fix the following build failure with gcc 4.8 raised since version 2.86:
option.c: In function 'one_opt':
option.c:2445:11: error: 'for' loop initial declarations are only allowed in C99 mode
for (char *p = arg; *p; p++) {
^
option.c:2445:11: note: use option -std=c99 or -std=gnu99 to compile your code
option.c:2453:11: error: 'for' loop initial declarations are only allowed in C99 mode
for (u8 i = 0; i < sizeof(daemon->umbrella_device); i++, arg+=2) {
^
Fixes:
- http://autobuild.buildroot.org/results/39b34a4e69fc10f4bd9d4ddb0ed8c0aae5741c84
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
To be treated as hex, the pattern must consist of only hex digits AND
contain at least one ':'. Thanks to Bengt-Erik Sandstrom who tripped
over a pattern consisting of a decimal number which was interpreted
surprisingly.
Previously, the prefix was limited to [8,16,24,32] for IPv4 and
to multiples of 4 for IPv6. This patch also makes the prefix-length optional
for --rev-server.
Inspired by a patch from DL6ER <dl6er@dl6er.de>, but completely
re-written by srk. All bugs are his.
Error: STRING_OVERFLOW (CWE-120): [#def99]
dnsmasq-2.86test7/src/option.c:801: fixed_size_dest: You might overrun the 100-character fixed-size string "buff" by copying "usage[i].arg" without checking the length.
# 799| if (usage[i].arg)
# 800| {
# 801|-> strcpy(buff, usage[i].arg);
# 802| for (j = 0; tab[j].handle; j++)
# 803| if (tab[j].handle == *(usage[i].arg))
Error: CLANG_WARNING: [#def100]
dnsmasq-2.86test7/src/option.c:962:3: warning[deadcode.DeadStores]: Value stored to 'domain' is never read
# 960| }
# 961|
# 962|-> domain += sprintf(domain, "in-addr.arpa");
# 963|
# 964| return 1;
Error: CLANG_WARNING: [#def101]
dnsmasq-2.86test7/src/option.c:981:3: warning[deadcode.DeadStores]: Value stored to 'domain' is never read
# 979| domain += sprintf(domain, "%.1x.", (i>>2) & 1 ? dig & 15 : dig >> 4);
# 980| }
# 981|-> domain += sprintf(domain, "ip6.arpa");
# 982|
# 983| return 1;
Error: RESOURCE_LEAK (CWE-772): [#def102] [important]
dnsmasq-2.86test7/src/option.c:1809: alloc_fn: Storage is returned from allocation function "opt_malloc".
dnsmasq-2.86test7/src/option.c:1809: var_assign: Assigning: "path" = storage returned from "opt_malloc(strlen(directory) + len + 2UL)".
dnsmasq-2.86test7/src/option.c:1810: noescape: Resource "path" is not freed or pointed-to in "strcpy". [Note: The source code implementation of the function has been overridden by a builtin model.]
dnsmasq-2.86test7/src/option.c:1811: noescape: Resource "path" is not freed or pointed-to in "strcat". [Note: The source code implementation of the function has been overridden by a builtin model.]
dnsmasq-2.86test7/src/option.c:1812: noescape: Resource "path" is not freed or pointed-to in "strcat". [Note: The source code implementation of the function has been overridden by a builtin model.]
dnsmasq-2.86test7/src/option.c:1815: noescape: Resource "path" is not freed or pointed-to in "stat".
dnsmasq-2.86test7/src/option.c:1809: overwrite_var: Overwriting "path" in "path = opt_malloc(strlen(directory) + len + 2UL)" leaks the storage that "path" points to.
# 1807| continue;
# 1808|
# 1809|-> path = opt_malloc(strlen(directory) + len + 2);
# 1810| strcpy(path, directory);
# 1811| strcat(path, "/");
Error: RESOURCE_LEAK (CWE-772): [#def103] [important]
dnsmasq-2.86test7/src/option.c:1809: alloc_fn: Storage is returned from allocation function "opt_malloc".
dnsmasq-2.86test7/src/option.c:1809: var_assign: Assigning: "path" = storage returned from "opt_malloc(strlen(directory) + len + 2UL)".
dnsmasq-2.86test7/src/option.c:1810: noescape: Resource "path" is not freed or pointed-to in "strcpy". [Note: The source code implementation of the function has been overridden by a builtin model.]
dnsmasq-2.86test7/src/option.c:1811: noescape: Resource "path" is not freed or pointed-to in "strcat". [Note: The source code implementation of the function has been overridden by a builtin model.]
dnsmasq-2.86test7/src/option.c:1812: noescape: Resource "path" is not freed or pointed-to in "strcat". [Note: The source code implementation of the function has been overridden by a builtin model.]
dnsmasq-2.86test7/src/option.c:1815: noescape: Resource "path" is not freed or pointed-to in "stat".
dnsmasq-2.86test7/src/option.c:1858: leaked_storage: Variable "path" going out of scope leaks the storage it points to.
# 1856| free(files);
# 1857| }
# 1858|-> break;
# 1859| }
# 1860|
Error: RESOURCE_LEAK (CWE-772): [#def104] [important]
dnsmasq-2.86test7/src/option.c:1996: alloc_fn: Storage is returned from allocation function "canonicalise_opt".
dnsmasq-2.86test7/src/option.c:1996: var_assign: Assigning: "name" = storage returned from "canonicalise_opt(arg)".
dnsmasq-2.86test7/src/option.c:1998: leaked_storage: Variable "name" going out of scope leaks the storage it points to.
# 1996| if (!(name = canonicalise_opt(arg)) ||
# 1997| (comma && !(target = canonicalise_opt(comma))))
# 1998|-> ret_err(_("bad MX name"));
# 1999|
# 2000| new = opt_malloc(sizeof(struct mx_srv_record));
Error: RESOURCE_LEAK (CWE-772): [#def106] [important]
dnsmasq-2.86test7/src/option.c:3477: alloc_fn: Storage is returned from allocation function "opt_malloc".
dnsmasq-2.86test7/src/option.c:3477: var_assign: Assigning: "new" = storage returned from "opt_malloc(96UL)".
dnsmasq-2.86test7/src/option.c:3618: leaked_storage: Variable "new" going out of scope leaks the storage it points to.
# 3616| sprintf(errstr, _("duplicate dhcp-host IP address %s"),
# 3617| daemon->addrbuff);
# 3618|-> return 0;
# 3619| }
# 3620| }
Error: RESOURCE_LEAK (CWE-772): [#def108] [important]
dnsmasq-2.86test7/src/option.c:3781: alloc_fn: Storage is returned from allocation function "opt_malloc".
dnsmasq-2.86test7/src/option.c:3781: var_assign: Assigning: "new" = storage returned from "opt_malloc(32UL)".
dnsmasq-2.86test7/src/option.c:3786: leaked_storage: Variable "new" going out of scope leaks the storage it points to.
# 3784|
# 3785| if (!(comma = split(arg)) || (len = strlen(comma)) == 0)
# 3786|-> ret_err(gen_err);
# 3787|
# 3788| new->wildcard = 0;
Error: RESOURCE_LEAK (CWE-772): [#def109] [important]
dnsmasq-2.86test7/src/option.c:3921: alloc_fn: Storage is returned from allocation function "opt_malloc".
dnsmasq-2.86test7/src/option.c:3921: var_assign: Assigning: "new" = storage returned from "opt_malloc(56UL)".
dnsmasq-2.86test7/src/option.c:3994: leaked_storage: Variable "new" going out of scope leaks the storage it points to.
# 3992| }
# 3993|
# 3994|-> ret_err(gen_err);
# 3995| }
# 3996|
Error: CLANG_WARNING: [#def111]
dnsmasq-2.86test7/src/option.c:4693:25: warning[deadcode.DeadStores]: Value stored to 'tmp' during its initialization is never read
# 4691| if (!canon)
# 4692| {
# 4693|-> struct name_list *tmp = new->names, *next;
# 4694| for (tmp = new->names; tmp; tmp = next)
# 4695|
For reasons unknown, I (srk) assumed that the orginal
substring domain matching algorithm was still in use,
where example.com would match eg. sexample.com
In fact the far more sensible label-based match, where
example.com (or .example.com) matches example.com and
www.example.com, but not sexample.com, has been in use
since release 2.22. This commit implements the 2.22 to 2.85
behaviour in the new domain-search code.
Thanks to Kevin Darbyshire-Bryant for spotting my mistake.
This extends query filtering support beyond what is currently possible
with the `--ipset` configuration option, by adding support for:
1) Specifying allowlists on a per-client basis, based on their
associated Linux connection track mark.
2) Dynamic configuration of allowlists via Ubus.
3) Reporting when a DNS query resolves or is rejected via Ubus.
4) DNS name patterns containing wildcards.
Disallowed queries are not forwarded; they are rejected
with a REFUSED error code.
Signed-off-by: Etan Kissling <etan_kissling@apple.com>
(addressed reviewer feedback)
Signed-off-by: Etan Kissling <etan.kissling@gmail.com>
This should be largely transparent, but it drastically
improves performance and reduces memory foot-print when
configuring large numbers domains of the form
local=/adserver.com/
or
local=/adserver.com/#
Lookup times now grow as log-to-base-2 of the number of domains,
rather than greater than linearly, as before.
The change makes multiple addresses associated with a domain work
address=/example.com/1.2.3.4
address=/example.com/5.6.7.8
It also handles multiple upstream servers for a domain better; using
the same try/retry alogrithms as non domain-specific servers. This
also applies to DNSSEC-generated queries.
Finally, some of the oldest and gnarliest code in dnsmasq has had
a significant clean-up. It's far from perfect, but it _is_ better.
Previously, without min-port or max-port configured, dnsmasq would
default to the compiled in defaults for those, which are 1024 and
65535. Now, when neither are configured, it defaults instead to
the kernel's ephemeral port range, which is typically
32768 to 60999 on Linux systems. This change eliminates the
possibility that dnsmasq may be using a registered port > 1024
when a long-running daemon starts up and wishes to claim it.
This change does likely slighly reduce the number of random ports
and therefore the protection from reply spoofing. The older
behaviour can be restored using the min-port and max-port config
switches should that be a concern.
