* g10/keydb.h: declare set_passphrase_from_environment_variable()
* g10/passphrase.c: set_passphrase_from_environment_variable() new
function
* g10/gpg.c: add new --passphrase-env argument, handle it.
--
There are problems or difficulties (to varying degrees) with all of
the techniques available for sending a passphrase directly to the
GnuPG process when --pinentry-mode=loopback:
* Passphrases on the command line often leak into the process table.
* Passphrases in a file often leak into the disk.
* Using an extra file descriptor to send a passphrase works well on
platforms that make it easy to allocate and use extra file
descriptors, but is pretty awkward on platforms that don't
facilitate this.
So this patch adds a new form of passphrase-passing, using an
environment variable. In POSIX shell, this looks like (for example):
mypass="IUuKctdEhH8' gpg --batch --pinentry-mode=loopback\
--passphrase-env=mypass --decrypt < message.txt
Hopefully, this is easier to use than --passphrase-fd on platforms or
language toolkits that don't facilitate file descriptor manipulation.
Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
07c19981da
