Re: [PATCH] crypto: sun8i-ce: fix multiple memory leaks in sun8i_ce_hash_run

From: Dongliang Mu
Date: Tue Aug 03 2021 - 01:57:48 EST


On Tue, Aug 3, 2021 at 2:25 AM Corentin Labbe <clabbe.montjoie@xxxxxxxxx> wrote:
>
> Le Mon, Jul 26, 2021 at 11:27:12PM +0800, Dongliang Mu a écrit :
> > In sun8i_ce_hash_run, all the dma_mmap_sg/single will cause memory leak
> > due to no corresponding unmap operation if errors happen.
> >
> > Fix this by adding error handling part for all the dma_mmap_sg/single.
> >
>
> I think it could be better worded, error handling is already there (but bad).

Sure. How about "Fix this by freeing the objects allocated by
dma_mmap_sg/single when errors occur."?

>
> > Fixes: 56f6d5aee88d ("crypto: sun8i-ce - support hash algorithms")
> > Signed-off-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx>
> > ---
> > .../crypto/allwinner/sun8i-ce/sun8i-ce-hash.c | 28 +++++++++----------
> > 1 file changed, 13 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-hash.c b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-hash.c
> > index 88194718a806..d454ad99deee 100644
> > --- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-hash.c
> > +++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-hash.c
> > @@ -286,16 +286,14 @@ int sun8i_ce_hash_run(struct crypto_engine *engine, void *breq)
> >
> > /* the padding could be up to two block. */
> > buf = kzalloc(bs * 2, GFP_KERNEL | GFP_DMA);
> > - if (!buf) {
> > - err = -ENOMEM;
> > - goto theend;
>
> Please keep all goto error for being consistent.

OK, no problem.

BTW, usually for the 1st malloc failure, I prefer returning with errno directly.

>
> > - }
> > + if (!buf)
> > + return -ENOMEM;
> > bf = (__le32 *)buf;
> >
> > result = kzalloc(digestsize, GFP_KERNEL | GFP_DMA);
> > if (!result) {
> > - err = -ENOMEM;
> > - goto theend;
> > + kfree(buf);
> > + return -ENOMEM;
> > }
> >
> > flow = rctx->flow;
> > @@ -321,7 +319,7 @@ int sun8i_ce_hash_run(struct crypto_engine *engine, void *breq)
> > if (nr_sgs <= 0 || nr_sgs > MAX_SG) {
> > dev_err(ce->dev, "Invalid sg number %d\n", nr_sgs);
> > err = -EINVAL;
> > - goto theend;
> > + goto err_result;
> > }
> >
> > len = areq->nbytes;
> > @@ -334,7 +332,7 @@ int sun8i_ce_hash_run(struct crypto_engine *engine, void *breq)
> > if (len > 0) {
> > dev_err(ce->dev, "remaining len %d\n", len);
> > err = -EINVAL;
> > - goto theend;
> > + goto err_unmap_sg;
> > }
> > addr_res = dma_map_single(ce->dev, result, digestsize, DMA_FROM_DEVICE);
> > cet->t_dst[0].addr = cpu_to_le32(addr_res);
> > @@ -342,7 +340,7 @@ int sun8i_ce_hash_run(struct crypto_engine *engine, void *breq)
> > if (dma_mapping_error(ce->dev, addr_res)) {
> > dev_err(ce->dev, "DMA map dest\n");
> > err = -EINVAL;
> > - goto theend;
> > + goto err_unmap_sg;
> > }
> >
> > byte_count = areq->nbytes;
> > @@ -392,7 +390,7 @@ int sun8i_ce_hash_run(struct crypto_engine *engine, void *breq)
> > if (dma_mapping_error(ce->dev, addr_pad)) {
> > dev_err(ce->dev, "DMA error on padding SG\n");
> > err = -EINVAL;
> > - goto theend;
> > + goto err_addr_res;
> > }
> >
> > if (ce->variant->hash_t_dlen_in_bits)
> > @@ -405,15 +403,15 @@ int sun8i_ce_hash_run(struct crypto_engine *engine, void *breq)
> > err = sun8i_ce_run_task(ce, flow, crypto_tfm_alg_name(areq->base.tfm));
> >
> > dma_unmap_single(ce->dev, addr_pad, j * 4, DMA_TO_DEVICE);
> > +err_addr_res:
> > + dma_unmap_single(ce->dev, addr_res, digestsize, DMA_FROM_DEVICE);
> > +err_unmap_sg:
> > dma_unmap_sg(ce->dev, areq->src, sg_nents(areq->src),
> > DMA_TO_DEVICE);
> > - dma_unmap_single(ce->dev, addr_res, digestsize, DMA_FROM_DEVICE);
> > -
> > -
> > memcpy(areq->result, result, algt->alg.hash.halg.digestsize);
>
> The result should be copied only when everything is ok. Please add a "if (!err)"

Sure.

>
> Thanks for your work
> Regards