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Ilya Dryomov authored
Starting with 4.9, kernel stacks may be vmalloced and therefore not guaranteed to be physically contiguous; the new CONFIG_VMAP_STACK option is enabled by default on x86. This makes it invalid to use on-stack buffers with the crypto scatterlist API, as sg_set_buf() expects a logical address and won't work with vmalloced addresses. There isn't a different (e.g. kvec-based) crypto API we could switch net/ceph/crypto.c to and the current scatterlist.h API isn't getting updated to accommodate this use case. Allocating a new header and padding for each operation is a non-starter, so do the en/decryption in-place on a single pre-assembled (header + data + padding) heap buffer. This is explicitly supported by the crypto API: "... the caller may provide the same scatter/gather list for the plaintext and cipher text. After the completion of the cipher operation, the plaintext data is replaced with the ciphertext data in case of an encryption and vice versa for a decryption." Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> Reviewed-by:
Sage Weil <sage@redhat.com>
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