Commit da6f9bf4 authored by Herbert Xu's avatar Herbert Xu
Browse files

crypto: krb5 - Use SG miter instead of doing it by hand 



The function crypto_shash_update_sg iterates through an SG by
hand.  It fails to handle corner cases such as SG entries longer
than a page.  Fix this by using the SG iterator.

Fixes: 348f5669 ("crypto/krb5: Implement the Kerberos5 rfc3961 get_mic and verify_mic")
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent fc8d5bba

crypto/krb5/rfc3961_simplified.c

+16 −21
Original line number Diff line number Diff line
@@ -67,9 +67,9 @@ 
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/random.h>

#include <linux/scatterlist.h>

#include <linux/skbuff.h>

#include <linux/slab.h>

#include <linux/highmem.h>

#include <linux/lcm.h>

#include <linux/rtnetlink.h>

#include <crypto/authenc.h>
@@ -83,26 +83,21 @@ 
int crypto_shash_update_sg(struct shash_desc *desc, struct scatterlist *sg,

			   size_t offset, size_t len)

{

	do {

		int ret;



		if (offset < sg->length) {

			struct page *page = sg_page(sg);

			void *p = kmap_local_page(page);

			void *q = p + sg->offset + offset;

			size_t seg = min_t(size_t, len, sg->length - offset);



			ret = crypto_shash_update(desc, q, seg);

			kunmap_local(p);

	struct sg_mapping_iter miter;

	size_t i, n;

	int ret = 0;



	sg_miter_start(&miter, sg, sg_nents(sg),

		       SG_MITER_FROM_SG | SG_MITER_LOCAL);

	for (i = 0; i < len; i += n) {

		sg_miter_next(&miter);

		n = min(miter.length, len - i);

		ret = crypto_shash_update(desc, miter.addr, n);

		if (ret < 0)

				return ret;

			len -= seg;

			offset = 0;

		} else {

			offset -= sg->length;

			break;

	}

	} while (len > 0 && (sg = sg_next(sg)));

	return 0;

	sg_miter_stop(&miter);

	return ret;

}



static int rfc3961_do_encrypt(struct crypto_sync_skcipher *tfm, void *iv,