From: Luis Henriques <lhenriques@suse.de>
To: David Howells <dhowells@redhat.com>,
Jarkko Sakkinen <jarkko@kernel.org>,
Eric Biggers <ebiggers@kernel.org>
Cc: keyrings@vger.kernel.org, linux-kernel@vger.kernel.org,
Luis Henriques <lhenriques@suse.de>
Subject: [RFC PATCH] keys: flush work when accessing /proc/key-users
Date: Wed, 6 Dec 2023 14:57:44 +0000 [thread overview]
Message-ID: <20231206145744.17277-1-lhenriques@suse.de> (raw)
Make sure the garbage collector has been run before cycling through all
the user keys.
Signed-off-by: Luis Henriques <lhenriques@suse.de>
---
Hi!
This patch is mostly for getting some feedback on how to fix an fstest
failing for ext4/fscrypt (generic/581). Basically, the test relies on the
data read from /proc/key-users to be up-to-date regarding the number of
keys a given user currently has. However, this file can't be trusted
because it races against the keys GC.
Using flush_work() seems to work (I can't reproduce the failure), but it
may be overkill. Or simply not acceptable. Maybe, as Eric suggested
elsewhere [1], there could be a synchronous key_put/revoke/invalidate/...,
which would wait for the key GC to do its work, although that probably
would require some more code re-work.
[1] https://lore.kernel.org/all/20231128173734.GD1148@sol.localdomain/
security/keys/gc.c | 6 ++++++
security/keys/internal.h | 1 +
security/keys/proc.c | 1 +
3 files changed, 8 insertions(+)
diff --git a/security/keys/gc.c b/security/keys/gc.c
index 3c90807476eb..57b5a54490a0 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -44,6 +44,12 @@ struct key_type key_type_dead = {
.name = ".dead",
};
+void key_flush_gc(void)
+{
+ kenter("");
+ flush_work(&key_gc_work);
+}
+
/*
* Schedule a garbage collection run.
* - time precision isn't particularly important
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 471cf36dedc0..fee1d0025d96 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -170,6 +170,7 @@ extern void keyring_restriction_gc(struct key *keyring,
extern void key_schedule_gc(time64_t gc_at);
extern void key_schedule_gc_links(void);
extern void key_gc_keytype(struct key_type *ktype);
+extern void key_flush_gc(void);
extern int key_task_permission(const key_ref_t key_ref,
const struct cred *cred,
diff --git a/security/keys/proc.c b/security/keys/proc.c
index d0cde6685627..2837e00a240a 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -277,6 +277,7 @@ static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
struct rb_node *_p;
loff_t pos = *_pos;
+ key_flush_gc();
spin_lock(&key_user_lock);
_p = key_user_first(seq_user_ns(p), &key_user_tree);
next reply other threads:[~2023-12-06 14:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-06 14:57 Luis Henriques [this message]
2023-12-06 16:04 ` [RFC PATCH] keys: flush work when accessing /proc/key-users David Howells
2023-12-06 17:55 ` Luis Henriques
2023-12-07 2:43 ` Eric Biggers
2023-12-11 14:02 ` David Howells
2023-12-12 3:03 ` Eric Biggers
2023-12-14 14:44 ` Luís Henriques
2024-01-15 12:03 ` [RFC PATCH v2] keys: update key quotas in key_put() Luis Henriques
2024-01-19 21:10 ` Jarkko Sakkinen
2024-01-22 11:50 ` Luis Henriques
2024-01-22 19:45 ` Jarkko Sakkinen
2024-01-24 22:12 ` Eric Biggers
2024-01-26 16:12 ` Luis Henriques
2024-01-27 6:42 ` Eric Biggers
2024-01-29 11:23 ` Luis Henriques
2023-12-07 4:33 ` [RFC PATCH] keys: flush work when accessing /proc/key-users Jarkko Sakkinen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231206145744.17277-1-lhenriques@suse.de \
--to=lhenriques@suse.de \
--cc=dhowells@redhat.com \
--cc=ebiggers@kernel.org \
--cc=jarkko@kernel.org \
--cc=keyrings@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).