extend ssl.openssl.ssl-conf-cmd to accept "SecurityLevel"
(lighttpd extension) and use the (string) value to call the
openssl-specific SSL_CTX_set_security_level()
replace /* fall through */ comment with __attribute_fallthrough__ macro
Note: not adding attribute to code with external origins:
xxhash.h (algo_xxhash.h)
ls-hpack/lshpack.c
so to avoid warnings, may need to compile with -Wno-implicit-fallthrough
remove ancient preprocessor logic which might define OPENSSL_NO_TLSEXT
The logic was added to base.h in https://redmine.lighttpd.net/issues/386
some 13 years ago, and today might cause more harm than good with other
TLS libraries which provide some level of openssl-compatiblity layer,
e.g. BoringSSL and LibreSSL
If building with an ancient version of openssl and building without
support for TLS extensions, then be sure that OPENSSL_NO_TLSEXT is
defined. (Alternatively, please consider using modern versions of
security libraries for better security.)
include wolfssl/options.h crypto lib config
after selecting crypto lib to use
wolfSSL does not prefix its defines with a wolfSSL-specific namespace
(so we would like to avoid unnecessarily polluting preproc namespace)
This commit further isolates wolfSSL after split from mod_openssl.
Cleans up some preprocessor logic that was put in place when using
the wolfSSL compatibility layer for openssl, before creating a
dedicated mod_wolfssl.
disabled by default, but can be enabled
(session tickets should be preferred)
applies to mod_openssl, mod_wolfssl, mod_nss
session cache is not currently implemented in mod_mbedtls or mod_gnutls
Using BIO_new_mem_buf() allows lighttpd to control file reads and
securely wiping memory, avoiding the use of BIO_s_file(), which
employs stdio and BIO internal copying without securely wiping memory.
BIO_new_mem_buf() is also much more performant than BIO_s_file()
or BIO_new_fd() without a buffering BIO, which might make many
syscalls reading a single character at a time.
BIO_new_mem_buf() appears to be supported by older OpenSSL versions
as well as by numerous OpenSSL-compatible APIs, e.g. in BoringSSL,
LibreSSL, WolfSSL
(expansion of buffer_string_lenth() inline function and CONST_BUF_LEN()
macro, which always check for NULL, appears to cause the analyzer to
believe that a pointer might be NULL in cases where it otherwise can
not be NULL)
x-ref:
http://clang-analyzer.llvm.org/faq.html
Prefer some WolfSSL native APIs when building with WolfSSL.
However, some functionality in WolfSSL is available only through the
WolfSSL compatibility layer for OpenSSL, so the effort to create a
native mod_wolfssl halted here.
ssl.stek-file to specify session ticket encryption key (STEK)
If ssl.stek-file is specified, it overrides builtin STEK rotation.
STEK file is checked for changes (stat()) once every 64 seconds.
STEK file should be stored in non-persistent storage,
e.g. /dev/shm/lighttpd/stek-file (in memory)
with appropriate permissions set to keep stek-file from being
read by other users. Where possible, systems should also be
configured without swap.
Admin should schedule an independent job to periodically
generate a new STEK up to 3 times during key lifetime
(lighttpd stores up to 3 keys)
format of binary file is:
4-byte - format version (always 0; for use if format changes)
4-byte - activation timestamp
4-byte - expiration timestamp
16-byte - session ticket key name
32-byte - session ticket HMAC encrpytion key
32-byte - session ticket AES encrpytion key
STEK file can be created with a command such as:
dd if=/dev/random bs=1 count=80 status=none | \
perl -e 'print pack("iii",0,time()+300,time()+86400),<>' \
> STEK-file.$$ && mv STEK-file.$$ STEK-file
The above delays activation time by 5 mins (+300 sec) to allow file to
be propagated to other machines. (admin must handle this independently)
If STEK generation is performed immediately prior to starting lighttpd,
admin should activate keys immediately (without +300).
server ticket encryption key (STEK) rotation occurs every 28800 seconds
(8 hours) and upon lighttpd server restart. While lighttpd is running,
(3) encryption keys are preserved, so tickets expire after 1 day.
If using lighttpd with multiple lighttpd workers, then restarting
lighttpd keeps the STEK in sync between lighttpd workers, though
restarting lighttpd three times a day might not be palatable.
Work is in progress to allow admin to supply new encryption keys.
Glenn Strauss