Deal gracefully with a NULL or empty scatterlist which can happen if both cryptlen and assoclen are zero and we're doing in-place AEAD encryption.

This fixes a crash when this causes us to try and map a NULL page, at least with some platforms / DMA mapping configs.

Cc: stable@vger.kernel.org # v4.19+ Reported-by: Geert Uytterhoeven geert+renesas@glider.be Tested-by: Geert Uytterhoeven geert+renesas@glider.be Signed-off-by: Gilad Ben-Yossef gilad@benyossef.com --- drivers/crypto/ccree/cc_buffer_mgr.c | 62 ++++++++++++---------------- drivers/crypto/ccree/cc_buffer_mgr.h | 1 + 2 files changed, 28 insertions(+), 35 deletions(-)

diff --git a/drivers/crypto/ccree/cc_buffer_mgr.c b/drivers/crypto/ccree/cc_buffer_mgr.c index a72586eccd81..b938ceae7ae7 100644 --- a/drivers/crypto/ccree/cc_buffer_mgr.c +++ b/drivers/crypto/ccree/cc_buffer_mgr.c @@ -87,6 +87,8 @@ static unsigned int cc_get_sgl_nents(struct device *dev, { unsigned int nents = 0;

+ *lbytes = 0; + while (nbytes && sg_list) { nents++; /* get the number of bytes in the last entry */ @@ -95,6 +97,7 @@ static unsigned int cc_get_sgl_nents(struct device *dev, nbytes : sg_list->length; sg_list = sg_next(sg_list); } + dev_dbg(dev, "nents %d last bytes %d\n", nents, *lbytes); return nents; } @@ -290,37 +293,25 @@ static int cc_map_sg(struct device *dev, struct scatterlist *sg, unsigned int nbytes, int direction, u32 *nents, u32 max_sg_nents, u32 *lbytes, u32 *mapped_nents) { - if (sg_is_last(sg)) { - /* One entry only case -set to DLLI */ - if (dma_map_sg(dev, sg, 1, direction) != 1) { - dev_err(dev, "dma_map_sg() single buffer failed\n"); - return -ENOMEM; - } - dev_dbg(dev, "Mapped sg: dma_address=%pad page=%p addr=%pK offset=%u length=%u\n", - &sg_dma_address(sg), sg_page(sg), sg_virt(sg), - sg->offset, sg->length); - *lbytes = nbytes; - *nents = 1; - *mapped_nents = 1; - } else { /*sg_is_last*/ - *nents = cc_get_sgl_nents(dev, sg, nbytes, lbytes); - if (*nents > max_sg_nents) { - *nents = 0; - dev_err(dev, "Too many fragments. current %d max %d\n", - *nents, max_sg_nents); - return -ENOMEM; - } - /* In case of mmu the number of mapped nents might - * be changed from the original sgl nents - */ - *mapped_nents = dma_map_sg(dev, sg, *nents, direction); - if (*mapped_nents == 0) { - *nents = 0; - dev_err(dev, "dma_map_sg() sg buffer failed\n"); - return -ENOMEM; - } + int ret = 0; + + *nents = cc_get_sgl_nents(dev, sg, nbytes, lbytes); + if (*nents > max_sg_nents) { + *nents = 0; + dev_err(dev, "Too many fragments. current %d max %d\n", + *nents, max_sg_nents); + return -ENOMEM; }

+ ret = dma_map_sg(dev, sg, *nents, direction); + if (dma_mapping_error(dev, ret)) { + *nents = 0; + dev_err(dev, "dma_map_sg() sg buffer failed %d\n", ret); + return -ENOMEM; + } + + *mapped_nents = ret; + return 0; }

@@ -555,11 +546,12 @@ void cc_unmap_aead_request(struct device *dev, struct aead_request *req) sg_virt(req->src), areq_ctx->src.nents, areq_ctx->assoc.nents, areq_ctx->assoclen, req->cryptlen);

- dma_unmap_sg(dev, req->src, sg_nents(req->src), DMA_BIDIRECTIONAL); + dma_unmap_sg(dev, req->src, areq_ctx->src.mapped_nents, + DMA_BIDIRECTIONAL); if (req->src != req->dst) { dev_dbg(dev, "Unmapping dst sgl: req->dst=%pK\n", sg_virt(req->dst)); - dma_unmap_sg(dev, req->dst, sg_nents(req->dst), + dma_unmap_sg(dev, req->dst, areq_ctx->dst.mapped_nents, DMA_BIDIRECTIONAL); } if (drvdata->coherent && @@ -881,7 +873,7 @@ static int cc_aead_chain_data(struct cc_drvdata *drvdata, &src_last_bytes); sg_index = areq_ctx->src_sgl->length; //check where the data starts - while (sg_index <= size_to_skip) { + while (src_mapped_nents && (sg_index <= size_to_skip)) { src_mapped_nents--; offset -= areq_ctx->src_sgl->length; sgl = sg_next(areq_ctx->src_sgl); @@ -908,7 +900,7 @@ static int cc_aead_chain_data(struct cc_drvdata *drvdata, size_for_map += crypto_aead_ivsize(tfm);

rc = cc_map_sg(dev, req->dst, size_for_map, DMA_BIDIRECTIONAL, - &areq_ctx->dst.nents, + &areq_ctx->dst.mapped_nents, LLI_MAX_NUM_OF_DATA_ENTRIES, &dst_last_bytes, &dst_mapped_nents); if (rc) @@ -921,7 +913,7 @@ static int cc_aead_chain_data(struct cc_drvdata *drvdata, offset = size_to_skip;

//check where the data starts - while (sg_index <= size_to_skip) { + while (dst_mapped_nents && sg_index <= size_to_skip) { dst_mapped_nents--; offset -= areq_ctx->dst_sgl->length; sgl = sg_next(areq_ctx->dst_sgl); @@ -1123,7 +1115,7 @@ int cc_map_aead_request(struct cc_drvdata *drvdata, struct aead_request *req) if (is_gcm4543) size_to_map += crypto_aead_ivsize(tfm); rc = cc_map_sg(dev, req->src, size_to_map, DMA_BIDIRECTIONAL, - &areq_ctx->src.nents, + &areq_ctx->src.mapped_nents, (LLI_MAX_NUM_OF_ASSOC_DATA_ENTRIES + LLI_MAX_NUM_OF_DATA_ENTRIES), &dummy, &mapped_nents); diff --git a/drivers/crypto/ccree/cc_buffer_mgr.h b/drivers/crypto/ccree/cc_buffer_mgr.h index af434872c6ff..827b6cb1236e 100644 --- a/drivers/crypto/ccree/cc_buffer_mgr.h +++ b/drivers/crypto/ccree/cc_buffer_mgr.h @@ -25,6 +25,7 @@ enum cc_sg_cpy_direct {

struct cc_mlli { cc_sram_addr_t sram_addr; + unsigned int mapped_nents; unsigned int nents; //sg nents unsigned int mlli_nents; //mlli nents might be different than the above };