From: "Michal Koutný" <mkoutny@suse.com> To: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, bpf@vger.kernel.org Cc: Tejun Heo <tj@kernel.org>, Aditya Kali <adityakali@google.com>, Serge Hallyn <serge.hallyn@canonical.com>, Roman Gushchin <roman.gushchin@linux.dev>, Yonghong Song <yhs@fb.com>, Muneendra Kumar <muneendra.kumar@broadcom.com>, Yosry Ahmed <yosryahmed@google.com>, Hao Luo <haoluo@google.com> Subject: [PATCH 2/4] cgroup: cgroup: Honor caller's cgroup NS when resolving cgroup id Date: Fri, 26 Aug 2022 18:52:36 +0200 [thread overview] Message-ID: <20220826165238.30915-3-mkoutny@suse.com> (raw) In-Reply-To: <20220826165238.30915-1-mkoutny@suse.com> Cgroup ids are resolved in the global scope. That may be needed sometime (in future) but currently it violates virtual view provided through cgroup namespaces. There are currently following users of the resolution: - fc_appid_store - bpf_iter_attach_cgroup - mem_cgroup_get_from_ino None of the is a called on behalf of kernel but the resolution is made with proper userspace context, hence the default to current->nsproxy makes sens. (This doesn't rule out cgroup_get_from_id with cgroup NS parameter in the future.) Since cgroup ids are defined on v2 hierarchy only, we simply check existence in the cgroup namespace by looking at ancestry on the default hierarchy. Fixes: 6b658c4863c1 ("scsi: cgroup: Add cgroup_get_from_id()") Signed-off-by: Michal Koutný <mkoutny@suse.com> --- kernel/cgroup/cgroup.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 1a8b50d15ebf..4ca90ee6b902 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6007,11 +6007,12 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) * cgroup_get_from_id : get the cgroup associated with cgroup id * @id: cgroup id * On success return the cgrp, on failure return NULL + * Only cgroups within current task's cgroup NS are valid. */ struct cgroup *cgroup_get_from_id(u64 id) { struct kernfs_node *kn; - struct cgroup *cgrp = NULL; + struct cgroup *cgrp = NULL, *root_cgrp; kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id); if (!kn) @@ -6024,8 +6025,18 @@ struct cgroup *cgroup_get_from_id(u64 id) cgrp = NULL; rcu_read_unlock(); - kernfs_put(kn); + + if (!cgrp) + goto out; + + spin_lock_irq(&css_set_lock); + root_cgrp = current_cgns_cgroup_from_root(&cgrp_dfl_root); + spin_unlock_irq(&css_set_lock); + if (!cgroup_is_descendant(cgrp, root_cgrp)) { + cgroup_put(cgrp); + cgrp = NULL; + } out: return cgrp; } -- 2.37.0
WARNING: multiple messages have this Message-ID (diff)
From: "Michal Koutný" <mkoutny@suse.com> To: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, bpf@vger.kernel.org Cc: Tejun Heo <tj@kernel.org>, Aditya Kali <adityakali@google.com>, Serge Hallyn <serge.hallyn@canonical.com>, Roman Gushchin <roman.gushchin@linux.dev>, Yonghong Song <yhs@fb.com>, Muneendra Kumar <muneendra.kumar@broadcom.com>, Yosry Ahmed <yosryahmed@google.com>, Hao Luo <haoluo@google.com> Subject: [PATCH 2/4] cgroup: cgroup: Honor caller's cgroup NS when resolving cgroup id Date: Fri, 26 Aug 2022 18:52:36 +0200 [thread overview] Message-ID: <20220826165238.30915-3-mkoutny@suse.com> (raw) In-Reply-To: <20220826165238.30915-1-mkoutny@suse.com> Cgroup ids are resolved in the global scope. That may be needed sometime (in future) but currently it violates virtual view provided through cgroup namespaces. There are currently following users of the resolution: - fc_appid_store - bpf_iter_attach_cgroup - mem_cgroup_get_from_ino None of the is a called on behalf of kernel but the resolution is made with proper userspace context, hence the default to current->nsproxy makes sens. (This doesn't rule out cgroup_get_from_id with cgroup NS parameter in the future.) Since cgroup ids are defined on v2 hierarchy only, we simply check existence in the cgroup namespace by looking at ancestry on the default hierarchy. Fixes: 6b658c4863c1 ("scsi: cgroup: Add cgroup_get_from_id()") Signed-off-by: Michal Koutn√Ω <mkoutny@suse.com> --- kernel/cgroup/cgroup.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 1a8b50d15ebf..4ca90ee6b902 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6007,11 +6007,12 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) * cgroup_get_from_id : get the cgroup associated with cgroup id * @id: cgroup id * On success return the cgrp, on failure return NULL + * Only cgroups within current task's cgroup NS are valid. */ struct cgroup *cgroup_get_from_id(u64 id) { struct kernfs_node *kn; - struct cgroup *cgrp = NULL; + struct cgroup *cgrp = NULL, *root_cgrp; kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id); if (!kn) @@ -6024,8 +6025,18 @@ struct cgroup *cgroup_get_from_id(u64 id) cgrp = NULL; rcu_read_unlock(); - kernfs_put(kn); + + if (!cgrp) + goto out; + + spin_lock_irq(&css_set_lock); + root_cgrp = current_cgns_cgroup_from_root(&cgrp_dfl_root); + spin_unlock_irq(&css_set_lock); + if (!cgroup_is_descendant(cgrp, root_cgrp)) { + cgroup_put(cgrp); + cgrp = NULL; + } out: return cgrp; } -- 2.37.0
next prev parent reply other threads:[~2022-08-26 16:53 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-08-26 16:52 [PATCH 0/4] Honor cgroup namespace when resolving cgroup id Michal Koutný 2022-08-26 16:52 ` Michal Koutný 2022-08-26 16:52 ` [PATCH 1/4] cgroup: Honor caller's cgroup NS when resolving path Michal Koutný 2022-08-26 16:52 ` Michal Koutný 2022-08-26 16:52 ` Michal Koutný [this message] 2022-08-26 16:52 ` [PATCH 2/4] cgroup: cgroup: Honor caller's cgroup NS when resolving cgroup id Michal Koutný 2022-08-26 16:52 ` [PATCH 3/4] cgroup: Homogenize cgroup_get_from_id() return value Michal Koutný 2022-08-26 16:52 ` Michal Koutný 2022-08-26 16:52 ` [PATCH 4/4] cgroup/bpf: Honor cgroup NS in cgroup_iter for ancestors Michal Koutný 2022-08-26 16:52 ` Michal Koutný 2022-08-26 17:41 ` Yosry Ahmed 2022-08-29 12:59 ` Michal Koutný 2022-08-29 12:59 ` Michal Koutný 2022-08-29 17:30 ` Yosry Ahmed 2022-08-29 17:30 ` Yosry Ahmed 2022-08-29 17:49 ` Tejun Heo 2022-08-29 18:02 ` Hao Luo 2022-08-26 20:59 ` [PATCH 0/4] Honor cgroup namespace when resolving cgroup id Tejun Heo 2022-08-26 21:08 ` Tejun Heo
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=20220826165238.30915-3-mkoutny@suse.com \ --to=mkoutny@suse.com \ --cc=adityakali@google.com \ --cc=bpf@vger.kernel.org \ --cc=cgroups@vger.kernel.org \ --cc=haoluo@google.com \ --cc=linux-kernel@vger.kernel.org \ --cc=muneendra.kumar@broadcom.com \ --cc=roman.gushchin@linux.dev \ --cc=serge.hallyn@canonical.com \ --cc=tj@kernel.org \ --cc=yhs@fb.com \ --cc=yosryahmed@google.com \ /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: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.