From a312e07a65fb598ed239b940434392721385c722 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 27 Oct 2023 13:30:17 -0700 Subject: [PATCH] crypto: adiantum - flush destination page before unmapping Upon additional review, the new fast path in adiantum_finish() is missing the call to flush_dcache_page() that scatterwalk_map_and_copy() was doing. It's apparently debatable whether flush_dcache_page() is actually needed, as per the discussion at https://lore.kernel.org/lkml/YYP1lAq46NWzhOf0@casper.infradead.org/T/#u. However, it appears that currently all the helper functions that write to a page, such as scatterwalk_map_and_copy(), memcpy_to_page(), and memzero_page(), do the dcache flush. So do it to be consistent. Fixes: dadf5e56c967 ("crypto: adiantum - add fast path for single-page messages") Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu --- crypto/adiantum.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/crypto/adiantum.c b/crypto/adiantum.c index 9ff3376f9ed3..60f3883b736a 100644 --- a/crypto/adiantum.c +++ b/crypto/adiantum.c @@ -300,7 +300,8 @@ static int adiantum_finish(struct skcipher_request *req) le128_sub(&rctx->rbuf.bignum, &rctx->rbuf.bignum, &rctx->header_hash); if (dst_nents == 1 && dst->offset + req->cryptlen <= PAGE_SIZE) { /* Fast path for single-page destination */ - void *virt = kmap_local_page(sg_page(dst)) + dst->offset; + struct page *page = sg_page(dst); + void *virt = kmap_local_page(page) + dst->offset; err = crypto_shash_digest(&rctx->u.hash_desc, virt, bulk_len, (u8 *)&digest); @@ -310,6 +311,7 @@ static int adiantum_finish(struct skcipher_request *req) } le128_sub(&rctx->rbuf.bignum, &rctx->rbuf.bignum, &digest); memcpy(virt + bulk_len, &rctx->rbuf.bignum, sizeof(le128)); + flush_dcache_page(page); kunmap_local(virt); } else { /* Slow path that works for any destination scatterlist */