crypto: sha512-mb - Protect sha512 mb ctx mgr access

The flusher and regular multi-buffer computation via mcryptd may race with another.
Add here a lock and turn off interrupt to to access multi-buffer
computation state cstate->mgr before a round of computation. This should
prevent the flusher code jumping in.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/x86/crypto/sha512-mb/sha512_mb.c

@@ -221,7 +221,7 @@ static struct sha512_hash_ctx *sha512_ctx_mgr_resubmit
 }
 
 static struct sha512_hash_ctx
-		*sha512_ctx_mgr_get_comp_ctx(struct sha512_ctx_mgr *mgr)
+		*sha512_ctx_mgr_get_comp_ctx(struct mcryptd_alg_cstate *cstate)
 {
 	/*
 	 * If get_comp_job returns NULL, there are no jobs complete.
@@ -233,11 +233,17 @@ static struct sha512_hash_ctx
 	 * Otherwise, all jobs currently being managed by the hash_ctx_mgr
 	 * still need processing.
 	 */
+	struct sha512_ctx_mgr *mgr;
 	struct sha512_hash_ctx *ctx;
+	unsigned long flags;
 
+	mgr = cstate->mgr;
+	spin_lock_irqsave(&cstate->work_lock, flags);
 	ctx = (struct sha512_hash_ctx *)
 				sha512_job_mgr_get_comp_job(&mgr->mgr);
-	return sha512_ctx_mgr_resubmit(mgr, ctx);
+	ctx = sha512_ctx_mgr_resubmit(mgr, ctx);
+	spin_unlock_irqrestore(&cstate->work_lock, flags);
+	return ctx;
 }
 
 static void sha512_ctx_mgr_init(struct sha512_ctx_mgr *mgr)
@@ -246,12 +252,17 @@ static void sha512_ctx_mgr_init(struct sha512_ctx_mgr *mgr)
 }
 
 static struct sha512_hash_ctx
-			*sha512_ctx_mgr_submit(struct sha512_ctx_mgr *mgr,
+			*sha512_ctx_mgr_submit(struct mcryptd_alg_cstate *cstate,
 					  struct sha512_hash_ctx *ctx,
 					  const void *buffer,
 					  uint32_t len,
 					  int flags)
 {
+	struct sha512_ctx_mgr *mgr;
+	unsigned long irqflags;
+
+	mgr = cstate->mgr;
+	spin_lock_irqsave(&cstate->work_lock, irqflags);
 	if (flags & (~HASH_ENTIRE)) {
 		/*
 		 * User should not pass anything other than FIRST, UPDATE, or
@@ -351,20 +362,26 @@ static struct sha512_hash_ctx
 		}
 	}
 
-	return sha512_ctx_mgr_resubmit(mgr, ctx);
+	ctx = sha512_ctx_mgr_resubmit(mgr, ctx);
+	spin_unlock_irqrestore(&cstate->work_lock, irqflags);
+	return ctx;
 }
 
-static struct sha512_hash_ctx *sha512_ctx_mgr_flush(struct sha512_ctx_mgr *mgr)
+static struct sha512_hash_ctx *sha512_ctx_mgr_flush(struct mcryptd_alg_cstate *cstate)
 {
+	struct sha512_ctx_mgr *mgr;
 	struct sha512_hash_ctx *ctx;
+	unsigned long flags;
 
+	mgr = cstate->mgr;
+	spin_lock_irqsave(&cstate->work_lock, flags);
 	while (1) {
 		ctx = (struct sha512_hash_ctx *)
 					sha512_job_mgr_flush(&mgr->mgr);
 
 		/* If flush returned 0, there are no more jobs in flight. */
 		if (!ctx)
-			return NULL;
+			break;
 
 		/*
 		 * If flush returned a job, resubmit the job to finish
@@ -378,8 +395,10 @@ static struct sha512_hash_ctx *sha512_ctx_mgr_flush(struct sha512_ctx_mgr *mgr)
 		 * the sha512_ctx_mgr still need processing. Loop.
 		 */
 		if (ctx)
-			return ctx;
+			break;
 	}
+	spin_unlock_irqrestore(&cstate->work_lock, flags);
+	return ctx;
 }
 
 static int sha512_mb_init(struct ahash_request *areq)
@@ -439,11 +458,11 @@ static int sha_finish_walk(struct mcryptd_hash_request_ctx **ret_rctx,
 		sha_ctx = (struct sha512_hash_ctx *)
 						ahash_request_ctx(&rctx->areq);
 		kernel_fpu_begin();
-		sha_ctx = sha512_ctx_mgr_submit(cstate->mgr, sha_ctx,
+		sha_ctx = sha512_ctx_mgr_submit(cstate, sha_ctx,
 						rctx->walk.data, nbytes, flag);
 		if (!sha_ctx) {
 			if (flush)
-				sha_ctx = sha512_ctx_mgr_flush(cstate->mgr);
+				sha_ctx = sha512_ctx_mgr_flush(cstate);
 		}
 		kernel_fpu_end();
 		if (sha_ctx)
@@ -471,11 +490,12 @@ static int sha_complete_job(struct mcryptd_hash_request_ctx *rctx,
 	struct sha512_hash_ctx *sha_ctx;
 	struct mcryptd_hash_request_ctx *req_ctx;
 	int ret;
+	unsigned long flags;
 
 	/* remove from work list */
-	spin_lock(&cstate->work_lock);
+	spin_lock_irqsave(&cstate->work_lock, flags);
 	list_del(&rctx->waiter);
-	spin_unlock(&cstate->work_lock);
+	spin_unlock_irqrestore(&cstate->work_lock, flags);
 
 	if (irqs_disabled())
 		rctx->complete(&req->base, err);
@@ -486,14 +506,14 @@ static int sha_complete_job(struct mcryptd_hash_request_ctx *rctx,
 	}
 
 	/* check to see if there are other jobs that are done */
-	sha_ctx = sha512_ctx_mgr_get_comp_ctx(cstate->mgr);
+	sha_ctx = sha512_ctx_mgr_get_comp_ctx(cstate);
 	while (sha_ctx) {
 		req_ctx = cast_hash_to_mcryptd_ctx(sha_ctx);
 		ret = sha_finish_walk(&req_ctx, cstate, false);
 		if (req_ctx) {
-			spin_lock(&cstate->work_lock);
+			spin_lock_irqsave(&cstate->work_lock, flags);
 			list_del(&req_ctx->waiter);
-			spin_unlock(&cstate->work_lock);
+			spin_unlock_irqrestore(&cstate->work_lock, flags);
 
 			req = cast_mcryptd_ctx_to_req(req_ctx);
 			if (irqs_disabled())
@@ -504,7 +524,7 @@ static int sha_complete_job(struct mcryptd_hash_request_ctx *rctx,
 				local_bh_enable();
 			}
 		}
-		sha_ctx = sha512_ctx_mgr_get_comp_ctx(cstate->mgr);
+		sha_ctx = sha512_ctx_mgr_get_comp_ctx(cstate);
 	}
 
 	return 0;
@@ -515,6 +535,7 @@ static void sha512_mb_add_list(struct mcryptd_hash_request_ctx *rctx,
 {
 	unsigned long next_flush;
 	unsigned long delay = usecs_to_jiffies(FLUSH_INTERVAL);
+	unsigned long flags;
 
 	/* initialize tag */
 	rctx->tag.arrival = jiffies;    /* tag the arrival time */
@@ -522,9 +543,9 @@ static void sha512_mb_add_list(struct mcryptd_hash_request_ctx *rctx,
 	next_flush = rctx->tag.arrival + delay;
 	rctx->tag.expire = next_flush;
 
-	spin_lock(&cstate->work_lock);
+	spin_lock_irqsave(&cstate->work_lock, flags);
 	list_add_tail(&rctx->waiter, &cstate->work_list);
-	spin_unlock(&cstate->work_lock);
+	spin_unlock_irqrestore(&cstate->work_lock, flags);
 
 	mcryptd_arm_flusher(cstate, delay);
 }
@@ -565,7 +586,7 @@ static int sha512_mb_update(struct ahash_request *areq)
 	sha_ctx = (struct sha512_hash_ctx *) ahash_request_ctx(areq);
 	sha512_mb_add_list(rctx, cstate);
 	kernel_fpu_begin();
-	sha_ctx = sha512_ctx_mgr_submit(cstate->mgr, sha_ctx, rctx->walk.data,
+	sha_ctx = sha512_ctx_mgr_submit(cstate, sha_ctx, rctx->walk.data,
 							nbytes, HASH_UPDATE);
 	kernel_fpu_end();
 
@@ -628,7 +649,7 @@ static int sha512_mb_finup(struct ahash_request *areq)
 	sha512_mb_add_list(rctx, cstate);
 
 	kernel_fpu_begin();
-	sha_ctx = sha512_ctx_mgr_submit(cstate->mgr, sha_ctx, rctx->walk.data,
+	sha_ctx = sha512_ctx_mgr_submit(cstate, sha_ctx, rctx->walk.data,
 								nbytes, flag);
 	kernel_fpu_end();
 
@@ -677,8 +698,7 @@ static int sha512_mb_final(struct ahash_request *areq)
 	/* flag HASH_FINAL and 0 data size */
 	sha512_mb_add_list(rctx, cstate);
 	kernel_fpu_begin();
-	sha_ctx = sha512_ctx_mgr_submit(cstate->mgr, sha_ctx, &data, 0,
-								HASH_LAST);
+	sha_ctx = sha512_ctx_mgr_submit(cstate, sha_ctx, &data, 0, HASH_LAST);
 	kernel_fpu_end();
 
 	/* check if anything is returned */
@@ -940,7 +960,7 @@ static unsigned long sha512_mb_flusher(struct mcryptd_alg_cstate *cstate)
 			break;
 		kernel_fpu_begin();
 		sha_ctx = (struct sha512_hash_ctx *)
-					sha512_ctx_mgr_flush(cstate->mgr);
+					sha512_ctx_mgr_flush(cstate);
 		kernel_fpu_end();
 		if (!sha_ctx) {
 			pr_err("sha512_mb error: nothing got flushed for"