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Miller" , Brian Masney , linux-arm-msm@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] crypto: qcom-rng - fix infinite loop on requests not multiple of WORD_SZ Date: Tue, 3 May 2022 13:50:10 +0200 Message-Id: <20220503115010.1750296-1-omosnace@redhat.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org The commit referenced in the Fixes tag removed the 'break' from the else branch in qcom_rng_read(), causing an infinite loop whenever 'max' is not a multiple of WORD_SZ. This can be reproduced e.g. by running: kcapi-rng -b 67 >/dev/null There are many ways to fix this without adding back the 'break', but they all seem more awkward than simply adding it back, so do just that. Tested on a machine with Qualcomm Amberwing processor. Fixes: a680b1832ced ("crypto: qcom-rng - ensure buffer for generate is completely filled") Cc: stable@vger.kernel.org Signed-off-by: Ondrej Mosnacek Reviewed-by: Brian Masney --- drivers/crypto/qcom-rng.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/crypto/qcom-rng.c b/drivers/crypto/qcom-rng.c index 11f30fd48c141..031b5f701a0a3 100644 --- a/drivers/crypto/qcom-rng.c +++ b/drivers/crypto/qcom-rng.c @@ -65,6 +65,7 @@ static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max) } else { /* copy only remaining bytes */ memcpy(data, &val, max - currsize); + break; } } while (currsize < max);