Messages in this thread | | | Date | Sat, 09 Aug 2003 23:33:52 +0300 | From | Mika Penttilä <> | Subject | cryptoapi incorrect struct page usage |
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It seems that cryptoapi usage wrt mm is not safe. At least both ipsec and cryptoloop practise these kinds of things :
example from net/xfrm/xfrm_algo.c
int skb_to_sgvec(struct sk_buff *skb, struct scatterlist *sg, int offset, int len) { int start = skb_headlen(skb); int i, copy = start - offset; int elt = 0;
if (copy > 0) { if (copy > len) copy = len; sg[elt].page = virt_to_page(skb->data + offset); sg[elt].offset = (unsigned long)(skb->data + offset) % PAGE_SIZE; sg[elt].length = copy;
so unpinned pages are passed to cryptoapi. Nothing prevents these pages from being swapped out. Something like get_user_pages() is needed to pin these pages for the duration of crypto operations. Comments?
--Mika
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