use constant time memcmp to thwart timing attacks.
The following message is by courtesy of brian m. carlson via security-list:
First, the code to verify the integrity hash (which is unfortunately MD5) is done with memcmp. This is not safe against timing attacks, so an attacker can tamper with the data and determine how much of the hash matches based on the amount of time it takes. This comparison should be done in a constant-time way.
The attack is relevant:
As for the timing attack on the keyring, it could be done with a malicious development container. Someone builds a development container based off a compromised image and mounts their home directory in it (say, so it can use their SSH keys or agent). This is a common thing to do these days[0]. The attacker can't read the memory of the gnome-keyring process, since it's outside the container and ptrace is disabled, but it's possible to tamper with the file in the home directory and run processes on the same CPU, so when the user attempts to decrypt the keyring, they can measure it.
[0] For example, as outlined here: https://code.visualstudio.com/docs/remote/containers