On Wed, Sep 28, 2016 at 3:54 PM, Jann Horn <jann@xxxxxxxxx> wrote: > SELinux attempts to make it possible to whitelist trustworthy sources of > code that may be mapped into memory, and Android makes use of this feature. > To prevent an attacker from bypassing this by modifying R+X memory through > /proc/$pid/mem or PTRACE_POKETEXT, it is necessary to call a security hook > in check_vma_flags(). If selinux policy allows PTRACE_POKETEXT, is it really so bad for that to result in code execution? > -struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode) > +struct mm_struct *proc_mem_open(struct inode *inode, > + const struct cred **object_cred, > + unsigned int mode) > { Why are you passing object_cred all over the place like this? You have an inode, and an inode implies a task. For that matter, would it possibly make sense to use MEMCG's mm->owner and get rid of object_cred entirely? I can see this causing issues in strange threading cases, e.g. accessing your own /proc/$$/mem vs another thread in your process's. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>