As kcalloc() may fail, check its return value to avoid a NULL pointer
dereference when passing the buffer to rng->read(). On allocation
failure, log the error and return since test_len() returns void.

Fixes: 2be0d806e25e ("crypto: caam - add a test for the RNG")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
changelog:
v3:
- Fix build error: test_len() returns void; return without a value.
- No functional changes beyond the allocation failure path.

v2:
- Return on allocation failure to avoid possible NULL dereference.
---
 drivers/crypto/caam/caamrng.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c
index b3d14a7f4dd1..0eb43c862516 100644
--- a/drivers/crypto/caam/caamrng.c
+++ b/drivers/crypto/caam/caamrng.c
@@ -181,7 +181,9 @@ static inline void test_len(struct hwrng *rng, size_t len, bool wait)
 	struct device *dev = ctx->ctrldev;
 
 	buf = kcalloc(CAAM_RNG_MAX_FIFO_STORE_SIZE, sizeof(u8), GFP_KERNEL);
-
+	if (!buf) {
+		return;
+	}
 	while (len > 0) {
 		read_len = rng->read(rng, buf, len, wait);
 
-- 
2.43.0

On Tue, Sep 23, 2025 at 08:44:18PM +0800, Guangshuo Li wrote:
> As kcalloc() may fail, check its return value to avoid a NULL pointer
> dereference when passing the buffer to rng->read(). On allocation
> failure, log the error and return since test_len() returns void.
> 
> Fixes: 2be0d806e25e ("crypto: caam - add a test for the RNG")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
> changelog:
> v3:
> - Fix build error: test_len() returns void; return without a value.
> - No functional changes beyond the allocation failure path.
> 
> v2:
> - Return on allocation failure to avoid possible NULL dereference.
> ---
>  drivers/crypto/caam/caamrng.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt