[PATCH 1/4] crypto: sun8i-ce-cipher - fix error handling in sun8i_ce_cipher_prepare()

[Ovidiu Panait]

Fix two DMA cleanup issues on the error path in sun8i_ce_cipher_prepare():

1] If dma_map_sg() fails for areq->dst, the device driver would try to free
   DMA memory it has not allocated in the first place. To fix this, on the
   "theend_sgs" error path, call dma unmap only if the corresponding dma
   map was successful.

2] If the dma_map_single() call for the IV fails, the device driver would
   try to free an invalid DMA memory address on the "theend_iv" path:
   ------------[ cut here ]------------
   DMA-API: sun8i-ce 1904000.crypto: device driver tries to free an invalid DMA memory address
   WARNING: CPU: 2 PID: 69 at kernel/dma/debug.c:968 check_unmap+0x123c/0x1b90
   Modules linked in: skcipher_example(O+)
   CPU: 2 UID: 0 PID: 69 Comm: 1904000.crypto- Tainted: G           O        6.15.0-rc3+ #24 PREEMPT
   Tainted: [O]=OOT_MODULE
   Hardware name: OrangePi Zero2 (DT)
   pc : check_unmap+0x123c/0x1b90
   lr : check_unmap+0x123c/0x1b90
   ...
   Call trace:
    check_unmap+0x123c/0x1b90 (P)
    debug_dma_unmap_page+0xac/0xc0
    dma_unmap_page_attrs+0x1f4/0x5fc
    sun8i_ce_cipher_do_one+0x1bd4/0x1f40
    crypto_pump_work+0x334/0x6e0
    kthread_worker_fn+0x21c/0x438
    kthread+0x374/0x664
    ret_from_fork+0x10/0x20
   ---[ end trace 0000000000000000 ]---

To fix this, check for !dma_mapping_error() before calling
dma_unmap_single() on the "theend_iv" path.

Fixes: 06f751b61329 ("crypto: allwinner - Add sun8i-ce Crypto Engine")
Signed-off-by: Ovidiu Panait <ovidiu.panait.oss at gmail.com>
---
 drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c
index 19b7fb4a93e8..05f67661553c 100644
--- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c
+++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-cipher.c
@@ -275,13 +275,16 @@ static int sun8i_ce_cipher_prepare(struct crypto_engine *engine, void *async_req
 	} else {
 		if (nr_sgs > 0)
 			dma_unmap_sg(ce->dev, areq->src, ns, DMA_TO_DEVICE);
-		dma_unmap_sg(ce->dev, areq->dst, nd, DMA_FROM_DEVICE);
+
+		if (nr_sgd > 0)
+			dma_unmap_sg(ce->dev, areq->dst, nd, DMA_FROM_DEVICE);
 	}
 
 theend_iv:
 	if (areq->iv && ivsize > 0) {
-		if (rctx->addr_iv)
+		if (!dma_mapping_error(ce->dev, rctx->addr_iv))
 			dma_unmap_single(ce->dev, rctx->addr_iv, rctx->ivlen, DMA_TO_DEVICE);
+
 		offset = areq->cryptlen - ivsize;
 		if (rctx->op_dir & CE_DECRYPTION) {
 			memcpy(areq->iv, chan->backup_iv, ivsize);
-- 
2.48.1