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2020-01-23privileges.go: remove a stale comment (#184)ebiggers
The workaround for Go versions before 1.10 was already removed by commit 3022c1603d96 ("Ensure setting user privileges is reversible").
2020-01-05Add keyring packageEric Biggers
In preparation for introducing support for the new filesystem-level keyrings, move the existing user keyring management code from security/keyring.go and crypto/crypto.go into a new package, 'keyring'. This package provides functions AddEncryptionKey, RemoveEncryptionKey, and GetEncryptionKeyStatus which delegate to either the filesystem keyring (added by a later patch) or to the user keyring. This provides a common interface to both types of keyrings, to the extent possible.
2019-09-08Fix various typos and grammatical errors (#141)ebiggers
These were found by a combination of manual review and a custom script that checks for common errors. Also removed an outdated sentence from the comment for setupBefore().
2018-09-02feat(spell-check): add make command for spell check.Deepesh Pathak
* Remove spelling mistakes in the repository * Add travis script to check for typos. * Add command to Makefile to check for typos. * Fixes #71
2018-08-23Ensure keyring privilege changes are reversibleJoe Richey joerichey@google.com
This change makes sure that, when we set the ruid and euid in order to get the user keyring linked into the current process keyring, we will always be able to reverse these changes (using a suid of 0). This fixes an issue where "su <user>" would result in a system error when called by an unprivileged user. It also explains exactly how and why we are making these privilege changes.
2018-08-23Ensure setting user privileges is reversibleJoe Richey joerichey@google.com
This change makes sure after dropping then elevating privileges for a process, the euid, guid, and groups are all the same as they were originally. This significantly simplifies the privilege logic. This fixes CVE-2018-6558, which allowed an unprivleged user to gain membership in the root group (gid 0) due to the groups not being properly reset in the process.
2018-03-25security: drop and regain privileges in all threadsEric Biggers
After enabling pam_fscrypt for "session" and creating a directory protected with a login protector, I was no longer able to log in as that user. The problem is that the Go runtime is creating threads after pam_fscrypt drops privileges, but pam_fscrypt is not re-acquiring privileges on those threads because the Go wrappers for setreuid(), setregid(), and setgroups() in the "sys/unix" package are using the raw syscalls which operate on the calling thread only. This violates glibc's assumption that all threads have the same uids and gids, causing it to abort() the process when a later module in the PAM stack (pam_mail in my case) tries to drop privileges using the glibc functions. Fix it by dropping and regaining privileges using the glibc functions rather than the "sys/unix" functions. This also avoids any possibility that privileges could be changed in a thread other than the "main" one for pam_fscrypt, since the Go runtime does not guarantee which OS-level thread runs what. It would be nice to also exit all Go worker threads before returning from pam_fscrypt, but the Go runtime doesn't seem to support that.
2017-09-01security: No more permenant privilege droppingJoseph Richey
This was creating an issue becasuse fully dropping privileges required spawning a goroutine and using rutime.DropOSThread().
2017-08-30security: Rewrite of keryings and permissionsJoe Richey
The keyring lookup functions no longer read from /proc/keys. Now they simply spawn a thread, drop privs, and check with GetKeyringID and KEY_SPEC_USER_KEYRING. See userKeyringID() for more info. The privileges functions have also been changed. Now the concept of setting privileges is seperate form the concept of setting up the keyrings.
2017-08-22security: Moved cache dropping functionJoe Richey joerichey@google.com
2017-08-22security: Fixed typo and improved error handlingJoe Richey joerichey@google.com
2017-08-17cmd/fscrypt: purge command now clears cacheJoe Richey joerichey@google.com