musl - an implementation of the standard library for Linux-based systems
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Rich Felker dec8f0a4fa dns query core: detect udp truncation at recv time
we already attempt to preclude this case by having res_send use a
sufficiently large temporary buffer even if the caller did not provide
one as large as or larger than the udp dns max of 512 bytes. however,
it's possible that the caller passed a custom-crafted query packet
using EDNS0, e.g. to get detailed DNSSEC results, with a larger udp
size allowance.

I have also seen claims that there are some broken nameservers in the
wild that do not honor the dns udp limit of 512 and send large answers
without the TC bit set, when the query was not using EDNS.

we generally don't aim to support broken nameservers, but in this case
both problems, if the latter is even real, have a common solution:
using recvmsg instead of recvfrom so we can examine the MSG_TRUNC
flag.
2022-10-19 14:01:31 -04:00
arch re-enable vdso clock_gettime on arm (32-bit) with workaround 2022-09-19 13:21:54 -04:00
compat/time32 fix null pointer dereference in setitimer time32 compat shim 2019-12-08 10:35:04 -05:00
crt remove unnecessary and problematic _Noreturn from crt/ldso startup 2019-06-25 19:05:40 -04:00
dist
include arpa/nameser.h: update RR types list 2022-09-22 18:44:44 -04:00
ldso process DT_RELR relocations in ldso-startup/static-pie 2022-09-12 08:30:36 -04:00
src dns query core: detect udp truncation at recv time 2022-10-19 14:01:31 -04:00
tools fix incorrect escaping in add-cfi.*.awk scripts 2020-01-20 15:57:29 -05:00
.gitignore remove obsolete gitignore rules 2016-07-06 00:21:25 -04:00
.mailmap update contributor name 2019-12-07 12:21:35 -05:00
COPYRIGHT add optimized aarch64 memcpy and memset 2020-06-26 17:49:51 -04:00
INSTALL fix typo in INSTALL 2020-11-29 00:46:38 -05:00
Makefile make mallocng the default malloc implementation 2020-06-30 15:38:27 -04:00
README update version reference in the README file 2014-06-25 14:16:53 -04:00
VERSION release 1.2.3 2022-04-07 13:12:40 -04:00
WHATSNEW release 1.2.3 2022-04-07 13:12:40 -04:00
configure remove ARMSUBARCH relic from configure 2022-04-27 08:45:18 -04:00
dynamic.list fix regression in access to optopt object 2018-11-19 13:20:41 -05:00

README

    musl libc

musl, pronounced like the word "mussel", is an MIT-licensed
implementation of the standard C library targetting the Linux syscall
API, suitable for use in a wide range of deployment environments. musl
offers efficient static and dynamic linking support, lightweight code
and low runtime overhead, strong fail-safe guarantees under correct
usage, and correctness in the sense of standards conformance and
safety. musl is built on the principle that these goals are best
achieved through simple code that is easy to understand and maintain.

The 1.1 release series for musl features coverage for all interfaces
defined in ISO C99 and POSIX 2008 base, along with a number of
non-standardized interfaces for compatibility with Linux, BSD, and
glibc functionality.

For basic installation instructions, see the included INSTALL file.
Information on full musl-targeted compiler toolchains, system
bootstrapping, and Linux distributions built on musl can be found on
the project website:

    http://www.musl-libc.org/