From 4ef04bdc0c9f98836d1638be516f6bf1bad55f69 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@kernel.org>
Date: Mon, 8 Jun 2026 17:58:46 +0000
Subject: [PATCH] crypto: qcom-rng - Allow zero as a random number

Zero is a valid random number and needs to be allowed.  Otherwise the
output is distinguishable from random.

Fixes: f29cd5bb64c2 ("crypto: qcom-rng - Add hw_random interface support")
Cc: stable@vger.kernel.org
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 drivers/crypto/qcom-rng.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/crypto/qcom-rng.c b/drivers/crypto/qcom-rng.c
index f31a7fe07ba7..7058bd98f9e9 100644
--- a/drivers/crypto/qcom-rng.c
+++ b/drivers/crypto/qcom-rng.c
@@ -65,8 +65,6 @@ static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max)
 			return ret;
 
 		val = readl_relaxed(rng->base + PRNG_DATA_OUT);
-		if (!val)
-			return -EINVAL;
 
 		if ((max - currsize) >= WORD_SZ) {
 			memcpy(data, &val, WORD_SZ);