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Commit 6238f921 authored by Dong Jia Shi's avatar Dong Jia Shi Committed by Cornelia Huck
Browse files

vfio: ccw: set ccw->cda to NULL defensively 



Let's avoid free on ccw->cda that points to a guest address
or an already freed memory area by setting it to NULL if memory
allocation didn't happen or failed.

Signed-off-by: default avatarDong Jia Shi <bjsdjshi@linux.ibm.com>
Message-Id: <20180523025645.8978-4-bjsdjshi@linux.ibm.com>
Signed-off-by: default avatarCornelia Huck <cohuck@redhat.com>
parent 5c1cfb1c

drivers/s390/cio/vfio_ccw_cp.c

+20 −11
Original line number Diff line number Diff line
@@ -502,7 +502,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, 
	struct ccw1 *ccw;

	struct pfn_array_table *pat;

	unsigned long *idaws;

	int idaw_nr;

	int ret;



	ccw = chain->ch_ccw + idx;
@@ -522,18 +522,19 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, 
	 * needed when translating a direct ccw to a idal ccw.

	 */

	pat = chain->ch_pat + idx;

	if (pfn_array_table_init(pat, 1))

		return -ENOMEM;

	idaw_nr = pfn_array_alloc_pin(pat->pat_pa, cp->mdev,

				      ccw->cda, ccw->count);

	if (idaw_nr < 0)

		return idaw_nr;

	ret = pfn_array_table_init(pat, 1);

	if (ret)

		goto out_init;



	ret = pfn_array_alloc_pin(pat->pat_pa, cp->mdev, ccw->cda, ccw->count);

	if (ret < 0)

		goto out_init;



	/* Translate this direct ccw to a idal ccw. */

	idaws = kcalloc(idaw_nr, sizeof(*idaws), GFP_DMA | GFP_KERNEL);

	idaws = kcalloc(ret, sizeof(*idaws), GFP_DMA | GFP_KERNEL);

	if (!idaws) {

		pfn_array_table_unpin_free(pat, cp->mdev);

		return -ENOMEM;

		ret = -ENOMEM;

		goto out_unpin;

	}

	ccw->cda = (__u32) virt_to_phys(idaws);

	ccw->flags |= CCW_FLAG_IDA;
@@ -541,6 +542,12 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, 
	pfn_array_table_idal_create_words(pat, idaws);



	return 0;



out_unpin:

	pfn_array_table_unpin_free(pat, cp->mdev);

out_init:

	ccw->cda = 0;

	return ret;

}



static int ccwchain_fetch_idal(struct ccwchain *chain,
@@ -570,7 +577,7 @@ static int ccwchain_fetch_idal(struct ccwchain *chain, 
	pat = chain->ch_pat + idx;

	ret = pfn_array_table_init(pat, idaw_nr);

	if (ret)

		return ret;

		goto out_init;



	/* Translate idal ccw to use new allocated idaws. */

	idaws = kzalloc(idaw_len, GFP_DMA | GFP_KERNEL);
@@ -602,6 +609,8 @@ static int ccwchain_fetch_idal(struct ccwchain *chain, 
	kfree(idaws);

out_unpin:

	pfn_array_table_unpin_free(pat, cp->mdev);

out_init:

	ccw->cda = 0;

	return ret;

}