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.
mod_openssl leverages cert callback in openssl 1.0.2 and later
(SSL_CTX_set_cert_cb())
server certificate chain
is now set in the cert callback
verify_store (for client certificate verification) (ssl.ca-file)
is now set in the cert callback
more carefully load sensitive files and clear temporary storage
(with openssl 1.1.1 and later)
x-ref:
"Lighttpd Returns Wrong Cert In Multi-cert Set-up"
https://redmine.lighttpd.net/issues/2842
set server certificate from callback in openssl 1.0.2 and later
(SSL_CTX_set_cert_cb())
For existing versions of lighttpd, certificate selection influenced by
ssl.cipher-list which can be used to set server cipher order preference
(along with ssl.honor-cipher-order = "enable", which is the default)
x-ref:
"Lighttpd Returns Wrong Cert In Multi-cert Set-up"
https://redmine.lighttpd.net/issues/2842
"lighttpd uses wrong pem-file"
https://redmine.lighttpd.net/issues/3009
server ticket encryption key (STEK) rotation occurs every 86400 seconds
and upon lighttpd server restart. If using lighttpd with multiple
lighttpd workers, then restarting lighttpd keeps the STEK in sync
between lighttpd workers.
report SSL_R_UNEXPECTED_EOF_WHILE_READING if debug.log-ssl-noise enabled
SSL_R_UNEXPECTED_EOF_WHILE_READING
added in openssl 1.1.1e and reverted in 1.1.1f, but kept in 3.0 branch
NB: r->tmp_buf == srv->tmp_buf (pointer is copied for quicker access)
NB: request read and write chunkqueues currently point to connection
chunkqueues; per-request and per-connection chunkqueues are
not distinct from one another
con->read_queue == r->read_queue
con->write_queue == r->write_queue
NB: in the future, a separate connection config may be needed for
connection-level module hooks. Similarly, might need to have
per-request chunkqueues separate from per-connection chunkqueues.
Should probably also have a request_reset() which is distinct from
connection_reset().
Glenn Strauss