If bad data is passed to ares_set_servers_csv() or
ares_set_servers_ports_csv() it will clear the existing channel
configured DNS servers, then a call to ares_send() will fail due
to a bad malloc which may have undefined behavior.
The fix now only clears existing servers on success. An additional
sanity check was added in ares_send() to ensure nservers >= 1 or
will result in ARES_ESERVFAIL.
Bug: https://c-ares.haxx.se/mail/c-ares-archive-2018-03/0000.shtml
Reported-by: Francisco Sedano Crippa
Add user-visible entrypoints ares_{get,set}_servers_ports(3), which
take struct ares_addr_port_node rather than struct ares_addr_node.
This structure includes a UDP and TCP port number; if this is set
to zero, the channel-wide port values are used as before.
Similarly, add a new ares_set_servers_ports_csv(3) entrypoint, which
is analogous to ares_set_servers(3) except it doesn't ignore any
specified port information; instead, any per-server specified port
is used as both the UDP and TCP port for that server.
The internal struct ares_addr is extended to hold the UDP/TCP ports,
stored in network order, with the convention that a value of zero
indicates that the channel-wide UDP/TCP port should be used.
For the internal implementation of ares_dup(3), shift to use the
_ports() version of the get/set functions, so port information is
transferred correctly to the new channel.
Update manpages, and add missing ares_set_servers_csv to the lists
while we're at it
Add a new ares_library_init_mem() initialization function for the
library which allows the library user to specify their own malloc,
realloc & free equivalents for use library-wide.
Store these function pointers in library-wide global variables,
defaulting to libc's malloc(), realloc() and free().
Change all calls to malloc, realloc and free to use the function pointer
instead. Also ensure that ares_strdup() is always available
(even if the local environment includes strdup(3)), and change the
library code to always use it.
Convert calls to calloc() to use ares_malloc() + memset
Add comments for the benefit of the lcov tool, marking
lines that cannot be hit. Typically these are fall-back
protection arms that are already covered by earlier checks,
and so it's not worth taking out the unhittable code (in case
someone changes the code between the two places in future).
Make sure that the symbols are always exported and present in c-ares.
Make the headers prefixed with 'ares'.
Removed the inet_ntop.h version as it no longer features any content.
Add 3 new functions to set the local binding for the out-going
socket connection, and add ares_set_servers_csv() to set a
list of servers at once as a comma-separated string.
Signed-off-by: Ben Greear <greearb@candelatech.com>
David Hotham
Brad House
David Drysdale
Gregor Jasny
Keith Shaw
Daniel Stenberg
Yang Tse
Ben Greear