From 72bbf11ba14bd7d5fbf31a1ec42fff608b657f74 Mon Sep 17 00:00:00 2001 From: Lothar Rubusch Date: Sat, 13 Jun 2026 20:20:37 +0000 Subject: [PATCH] crypto: atmel-sha204a - fix heap info leak on I2C transfer failure The nonblocking RNG path allocates a work_data structure to track the state of an in-flight asynchronous I2C request. This pointer is stored in rng->priv and later consumed by the read path once the transaction completes. If the underlying I2C transfer fails, the completion callback is invoked with a non-zero status. In this case, the allocated work_data is not usable for producing RNG output and must not remain associated with the hwrng state. Previously, the failure path only logged a warning but left the pointer state uncleared, which can result in subsequent read attempts observing stale state and interpreting it as valid completion data. Fix this by freeing the pending work_data. The I2C transaction reports an error. This ensures that failed requests do not leave residual state behind that could be interpreted as valid RNG data on later reads. Clearing rng->priv is done at the subsequent call to nonblocking read. Fixes: da001fb651b0 ("crypto: atmel-i2c - add support for SHA204A random number generator") Signed-off-by: Lothar Rubusch Assisted-by: Gemini:1.5 Pro [google] Reviewed-by: Thorsten Blum Signed-off-by: Herbert Xu --- drivers/crypto/atmel-sha204a.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c index 4c9af737b33a..5eb76245347d 100644 --- a/drivers/crypto/atmel-sha204a.c +++ b/drivers/crypto/atmel-sha204a.c @@ -31,10 +31,14 @@ static void atmel_sha204a_rng_done(struct atmel_i2c_work_data *work_data, struct atmel_i2c_client_priv *i2c_priv = work_data->ctx; struct hwrng *rng = areq; - if (status) + if (status) { dev_warn_ratelimited(&i2c_priv->client->dev, "i2c transaction failed (%d)\n", status); + kfree(work_data); + atomic_dec(&i2c_priv->tfm_count); + return; + } rng->priv = (unsigned long)work_data; atomic_dec(&i2c_priv->tfm_count);