From 999bd704b0b641527a5ed46f0d969deff8cfa68b Mon Sep 17 00:00:00 2001 From: Massimiliano Pellizzer Date: Tue, 13 Jan 2026 09:09:43 +0100 Subject: apparmor: replace recursive profile removal with iterative approach commit ab09264660f9de5d05d1ef4e225aa447c63a8747 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- 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 105706abf281..f6869ea00d1d 100644 --- a/security/apparmor/policy.c +++ b/security/apparmor/policy.c @@ -184,19 +184,43 @@ 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); -- cgit v1.2.3