Re: [PATCH ima-evm-utils] Improve memory handling for private keys and passwords
From: Vitaly Chikunov <hidden>
Date: 2021-08-12 21:46:23
Hi, On Fri, Aug 13, 2021 at 12:21:43AM +0300, Vitaly Chikunov wrote:
After CRYPTO_secure_malloc_init OpenSSL will store private keys in secure heap. This facility is only available since OpenSSL_1_1_0-pre1 and enabled for 'ima_sign', 'sign', 'sign_hash', and 'hmac'.
setvbuf(3) _IONBF is used to hopefully avoid private key and password being stored inside of stdio buffers.
I should note that usefulness of this method (of avoiding buffering) is not proven. I don't find other implementations doing it. So, I'm open to suggestion of removing it. Thanks,
Unfortunately, secure heap is not used for the passwords (`-p') due to absence of its support in the older OpenSSL where ima-evem-utils still should work, thus simple cleansing of password memory is used where possible to shorten its lifespan. Signed-off-by: Vitaly Chikunov <redacted> --- Perhaps, it will conflict with Bruno's patch, we should decide which one goes first if this will be accepted. src/evmctl.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++--- src/libimaevm.c | 14 ++++++++- 2 files changed, 92 insertions(+), 5 deletions(-)