From:   Marek Vasut <marex@denx.de>
To:     linux-crypto@vger.kernel.org
Cc:     Marek Vasut <marex@denx.de>, stable@vger.kernel.org,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Fabien Dessenne <fabien.dessenne@st.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Lionel Debieve <lionel.debieve@st.com>,
        Nicolas Toromanoff <nicolas.toromanoff@st.com>,
        linux-arm-kernel@lists.infradead.org,
        linux-stm32@st-md-mailman.stormreply.com
Subject: [PATCH] crypto: stm32/crc32 - Fix kernel BUG triggered in probe()
Date:   Mon, 20 Dec 2021 20:50:22 +0100
Message-Id: <20211220195022.1387104-1-marex@denx.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The include/linux/crypto.h struct crypto_alg field cra_driver_name description
states "Unique name of the transformation provider. " ... " this contains the
name of the chip or provider and the name of the transformation algorithm."

In case of the stm32-crc driver, field cra_driver_name is identical for all
registered transformation providers and set to the name of the driver itself,
which is incorrect. This patch fixes it by assigning a unique cra_driver_name
to each registered transformation provider.

The kernel crash is triggered when the driver calls crypto_register_shashes()
which calls crypto_register_shash(), which calls crypto_register_alg(), which
calls __crypto_register_alg(), which returns -EEXIST, which is propagated
back through this call chain. Upon -EEXIST from crypto_register_shash(), the
crypto_register_shashes() starts unregistering the providers back, and calls
crypto_unregister_shash(), which calls crypto_unregister_alg(), and this is
where the BUG() triggers due to incorrect cra_refcnt.

Fixes: b51dbe90912a ("crypto: stm32 - Support for STM32 CRC32 crypto module")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: <stable@vger.kernel.org> # 4.12+
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Fabien Dessenne <fabien.dessenne@st.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Lionel Debieve <lionel.debieve@st.com>
Cc: Nicolas Toromanoff <nicolas.toromanoff@st.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-crypto@vger.kernel.org
---
 drivers/crypto/stm32/stm32-crc32.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/stm32/stm32-crc32.c b/drivers/crypto/stm32/stm32-crc32.c
index 75867c0b0017..be1bf39a317d 100644
--- a/drivers/crypto/stm32/stm32-crc32.c
+++ b/drivers/crypto/stm32/stm32-crc32.c
@@ -279,7 +279,7 @@ static struct shash_alg algs[] = {
 		.digestsize     = CHKSUM_DIGEST_SIZE,
 		.base           = {
 			.cra_name               = "crc32",
-			.cra_driver_name        = DRIVER_NAME,
+			.cra_driver_name        = "stm32-crc32-crc32",
 			.cra_priority           = 200,
 			.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize          = CHKSUM_BLOCK_SIZE,
@@ -301,7 +301,7 @@ static struct shash_alg algs[] = {
 		.digestsize     = CHKSUM_DIGEST_SIZE,
 		.base           = {
 			.cra_name               = "crc32c",
-			.cra_driver_name        = DRIVER_NAME,
+			.cra_driver_name        = "stm32-crc32-crc32c",
 			.cra_priority           = 200,
 			.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize          = CHKSUM_BLOCK_SIZE,
-- 
2.34.1