From 6acf79cb236bc995cee11147eb6941c47c373e48 Mon Sep 17 00:00:00 2001 From: Massimiliano Pellizzer Date: Tue, 13 Jan 2026 09:09:43 +0100 Subject: [PATCH] [PATCH 03/11] apparmor: replace recursive profile removal with iterative approach The profile removal code uses recursion when removing nested profiles, which can lead to kernel stack exhaustion and system crashes. Reproducer: $ pf='a'; for ((i=0; i<1024; i++)); do echo -e "profile $pf { \n }" | apparmor_parser -K -a; pf="$pf//x"; done $ echo -n a > /sys/kernel/security/apparmor/.remove Replace the recursive __aa_profile_list_release() approach with an iterative approach in __remove_profile(). The function repeatedly finds and removes leaf profiles until the entire subtree is removed, maintaining the same removal semantic without recursion. Fixes: c88d4c7b049e ("AppArmor: core policy routines") Reported-by: Qualys Security Advisory Tested-by: Salvatore Bonaccorso Reviewed-by: Georgia Garcia Reviewed-by: Cengiz Can Signed-off-by: Massimiliano Pellizzer Signed-off-by: John Johansen Gbp-Pq: Topic bugfix/all/qsa-2026-apparmor Gbp-Pq: Name 0003-apparmor-replace-recursive-profile-removal-with-iter.patch --- security/apparmor/policy.c | 30 +++++++++++++++++++++++++++--- 1 file changed, 27 insertions(+), 3 deletions(-) diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c index 50d5345ff5c..5a137f58f6f 100644 --- a/security/apparmor/policy.c +++ b/security/apparmor/policy.c @@ -183,19 +183,43 @@ static void __list_remove_profile(struct aa_profile *profile) } /** - * __remove_profile - remove old profile, and children - * @profile: profile to be replaced (NOT NULL) + * __remove_profile - remove profile, and children + * @profile: profile to be removed (NOT NULL) * * Requires: namespace list lock be held, or list not be shared */ static void __remove_profile(struct aa_profile *profile) { + struct aa_profile *curr, *to_remove; + AA_BUG(!profile); AA_BUG(!profile->ns); AA_BUG(!mutex_is_locked(&profile->ns->lock)); /* release any children lists first */ - __aa_profile_list_release(&profile->base.profiles); + if (!list_empty(&profile->base.profiles)) { + curr = list_first_entry(&profile->base.profiles, struct aa_profile, base.list); + + while (curr != profile) { + + while (!list_empty(&curr->base.profiles)) + curr = list_first_entry(&curr->base.profiles, + struct aa_profile, base.list); + + to_remove = curr; + if (!list_is_last(&to_remove->base.list, + &aa_deref_parent(curr)->base.profiles)) + curr = list_next_entry(to_remove, base.list); + else + curr = aa_deref_parent(curr); + + /* released by free_profile */ + aa_label_remove(&to_remove->label); + __aafs_profile_rmdir(to_remove); + __list_remove_profile(to_remove); + } + } + /* released by free_profile */ aa_label_remove(&profile->label); __aafs_profile_rmdir(profile); -- 2.30.2