From c5772ced573ea4be02b6a95a0b7d8998ae8a6830 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= Date: Tue, 21 Jul 2026 15:36:01 -0400 Subject: [PATCH] landlock: Account all audit data allocations to user space MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit b232bd12789fa57405b5092f28788be97aae9999 ] Mark the kzalloc_flex() of struct landlock_details with GFP_KERNEL_ACCOUNT so the allocation is charged to the calling task, like the other Landlock per-domain allocations which have used GFP_KERNEL_ACCOUNT forever. Every property of landlock_details is caller-attributable: allocated by landlock_restrict_self(2), owned by the caller's landlock_hierarchy, contents are the caller's pid, uid, comm, and exe_path, lifetime bounded by the caller's domain. While the caller may not know nor control the size of this allocation (i.e. exe_path), this data should still be accounted for it. The deciding factor is whether userspace can trigger the allocation, not whether the size of the data is known nor controlled by the caller. This aligns with the kmemcg accounting policy established by commit 5d097056c9a0 ("kmemcg: account certain kmem allocations to memcg"). No new failure modes: the hierarchy and ruleset are allocated before details and are already accounted, so landlock_restrict_self(2) already returns -ENOMEM under memcg pressure. This change widens that existing failure window slightly; it does not introduce a new error code. Cc: Günther Noack Cc: Paul Moore Cc: stable@vger.kernel.org Fixes: 1d636984e088 ("landlock: Add AUDIT_LANDLOCK_DOMAIN and log domain status") Link: https://patch.msgid.link/20260513180309.165840-1-mic@digikod.net Signed-off-by: Mickaël Salaün Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- security/landlock/domain.c | 9 +++++---- security/landlock/domain.h | 5 +---- 2 files changed, 6 insertions(+), 8 deletions(-) diff --git a/security/landlock/domain.c b/security/landlock/domain.c index a1377c7d7e9b..74fbe8de1fc5 100644 --- a/security/landlock/domain.c +++ b/security/landlock/domain.c @@ -90,11 +90,12 @@ static struct landlock_details *get_current_details(void) return ERR_CAST(buffer); /* - * Create the new details according to the path's length. Do not - * allocate with GFP_KERNEL_ACCOUNT because it is independent from the - * caller. + * Create the new details according to the path's length. Account to + * the calling task's memcg, like the other Landlock per-domain + * allocations, even if it may not control the related size. */ - details = kzalloc_flex(*details, exe_path, path_size); + details = + kzalloc_flex(*details, exe_path, path_size, GFP_KERNEL_ACCOUNT); if (!details) return ERR_PTR(-ENOMEM); diff --git a/security/landlock/domain.h b/security/landlock/domain.h index 7fb70b25f85a..e3525da27b93 100644 --- a/security/landlock/domain.h +++ b/security/landlock/domain.h @@ -33,10 +33,7 @@ enum landlock_log_status { * Rarely accessed, mainly when logging the first domain's denial. * * The contained pointers are initialized at the domain creation time and never - * changed again. Contrary to most other Landlock object types, this one is - * not allocated with GFP_KERNEL_ACCOUNT because its size may not be under the - * caller's control (e.g. unknown exe_path) and the data is not explicitly - * requested nor used by tasks. + * changed again. */ struct landlock_details { /**