In the Linux kernel, the following vulnerability has been resolved:
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.