* [PATCH] crypto: mxs-dcp: Enable user-space access to AES with hardware-bound keys
@ 2024-09-13 10:58 Tomas Paukrt
2024-09-14 8:35 ` Herbert Xu
0 siblings, 1 reply; 6+ messages in thread
From: Tomas Paukrt @ 2024-09-13 10:58 UTC (permalink / raw)
To: linux-crypto
Cc: Herbert Xu, David S. Miller, Shawn Guo, Sascha Hauer,
Pengutronix Kernel Team, Fabio Estevam, imx, linux-arm-kernel
Add an option to enable user-space access to cbc(paes) and ecb(paes)
cipher algorithms via AF_ALG.
Signed-off-by: Tomas Paukrt <tomaspaukrt@email.cz>
---
drivers/crypto/Kconfig | 13 +++++++++++++
drivers/crypto/mxs-dcp.c | 8 ++++++++
2 files changed, 21 insertions(+)
diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 94f23c6..4637c6f 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -460,6 +460,19 @@ config CRYPTO_DEV_MXS_DCP
To compile this driver as a module, choose M here: the module
will be called mxs-dcp.
+config CRYPTO_DEV_MXS_DCP_USER_PAES
+ bool "Enable user-space access to AES with hardware-bound keys"
+ depends on CRYPTO_DEV_MXS_DCP && CRYPTO_USER_API_SKCIPHER
+ default n
+ help
+ Say Y to enable user-space access to cbc(paes) and ecb(paes)
+ cipher algorithms via AF_ALG.
+
+ In scenarios with untrustworthy users-pace, this may enable
+ decryption of sensitive information.
+
+ If unsure, say N.
+
source "drivers/crypto/cavium/cpt/Kconfig"
source "drivers/crypto/cavium/nitrox/Kconfig"
source "drivers/crypto/marvell/Kconfig"
diff --git a/drivers/crypto/mxs-dcp.c b/drivers/crypto/mxs-dcp.c
index c82775d..84df1cb 100644
--- a/drivers/crypto/mxs-dcp.c
+++ b/drivers/crypto/mxs-dcp.c
@@ -944,7 +944,11 @@ static struct skcipher_alg dcp_aes_algs[] = {
.base.cra_driver_name = "ecb-paes-dcp",
.base.cra_priority = 401,
.base.cra_alignmask = 15,
+#ifdef CONFIG_CRYPTO_DEV_MXS_DCP_USER_PAES
+ .base.cra_flags = CRYPTO_ALG_ASYNC,
+#else
.base.cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_INTERNAL,
+#endif
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct dcp_async_ctx),
.base.cra_module = THIS_MODULE,
@@ -960,7 +964,11 @@ static struct skcipher_alg dcp_aes_algs[] = {
.base.cra_driver_name = "cbc-paes-dcp",
.base.cra_priority = 401,
.base.cra_alignmask = 15,
+#ifdef CONFIG_CRYPTO_DEV_MXS_DCP_USER_PAES
+ .base.cra_flags = CRYPTO_ALG_ASYNC,
+#else
.base.cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_INTERNAL,
+#endif
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct dcp_async_ctx),
.base.cra_module = THIS_MODULE,
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] crypto: mxs-dcp: Enable user-space access to AES with hardware-bound keys
2024-09-13 10:58 [PATCH] crypto: mxs-dcp: Enable user-space access to AES with hardware-bound keys Tomas Paukrt
@ 2024-09-14 8:35 ` Herbert Xu
2024-09-14 11:32 ` Tomas Paukrt
0 siblings, 1 reply; 6+ messages in thread
From: Herbert Xu @ 2024-09-14 8:35 UTC (permalink / raw)
To: Tomas Paukrt
Cc: linux-crypto, David S. Miller, Shawn Guo, Sascha Hauer,
Pengutronix Kernel Team, Fabio Estevam, imx, linux-arm-kernel
On Fri, Sep 13, 2024 at 12:58:21PM +0200, Tomas Paukrt wrote:
> Add an option to enable user-space access to cbc(paes) and ecb(paes)
> cipher algorithms via AF_ALG.
>
> Signed-off-by: Tomas Paukrt <tomaspaukrt@email.cz>
> ---
> drivers/crypto/Kconfig | 13 +++++++++++++
> drivers/crypto/mxs-dcp.c | 8 ++++++++
> 2 files changed, 21 insertions(+)
>
> diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
> index 94f23c6..4637c6f 100644
> --- a/drivers/crypto/Kconfig
> +++ b/drivers/crypto/Kconfig
> @@ -460,6 +460,19 @@ config CRYPTO_DEV_MXS_DCP
> To compile this driver as a module, choose M here: the module
> will be called mxs-dcp.
>
> +config CRYPTO_DEV_MXS_DCP_USER_PAES
> + bool "Enable user-space access to AES with hardware-bound keys"
> + depends on CRYPTO_DEV_MXS_DCP && CRYPTO_USER_API_SKCIPHER
> + default n
> + help
> + Say Y to enable user-space access to cbc(paes) and ecb(paes)
> + cipher algorithms via AF_ALG.
> +
> + In scenarios with untrustworthy users-pace, this may enable
> + decryption of sensitive information.
> +
> + If unsure, say N.
> +
Why not just expose it uncondtionally?
Cheers,
--
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
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] crypto: mxs-dcp: Enable user-space access to AES with hardware-bound keys
2024-09-14 8:35 ` Herbert Xu
@ 2024-09-14 11:32 ` Tomas Paukrt
2024-09-14 11:38 ` Herbert Xu
0 siblings, 1 reply; 6+ messages in thread
From: Tomas Paukrt @ 2024-09-14 11:32 UTC (permalink / raw)
To: Herbert Xu
Cc: linux-crypto, David S. Miller, Shawn Guo, Sascha Hauer,
Pengutronix Kernel Team, Fabio Estevam, imx, linux-arm-kernel
> Why not just expose it uncondtionally?
Please see the comment in the following patch: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3d16af0b4cfac4b2c3b238e2ec37b38c2f316978
The goal of this change is to allow some users to use AES with hardware-bound keys from user-space without compromising others.
Best regards
Tomas
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] crypto: mxs-dcp: Enable user-space access to AES with hardware-bound keys
2024-09-14 11:32 ` Tomas Paukrt
@ 2024-09-14 11:38 ` Herbert Xu
2024-09-14 12:41 ` Tomas Paukrt
0 siblings, 1 reply; 6+ messages in thread
From: Herbert Xu @ 2024-09-14 11:38 UTC (permalink / raw)
To: Tomas Paukrt
Cc: linux-crypto, David S. Miller, Shawn Guo, Sascha Hauer,
Pengutronix Kernel Team, Fabio Estevam, imx, linux-arm-kernel
On Sat, Sep 14, 2024 at 01:32:37PM +0200, Tomas Paukrt wrote:
>
> Please see the comment in the following patch: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3d16af0b4cfac4b2c3b238e2ec37b38c2f316978
>
> The goal of this change is to allow some users to use AES with hardware-bound keys from user-space without compromising others.
In that case I would suggest introducing a flag so that the key
can only be accessed through the keyring subsystem.
Cheers,
--
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
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] crypto: mxs-dcp: Enable user-space access to AES with hardware-bound keys
2024-09-14 11:38 ` Herbert Xu
@ 2024-09-14 12:41 ` Tomas Paukrt
2024-09-17 5:25 ` Herbert Xu
0 siblings, 1 reply; 6+ messages in thread
From: Tomas Paukrt @ 2024-09-14 12:41 UTC (permalink / raw)
To: Herbert Xu
Cc: linux-crypto, David S. Miller, Shawn Guo, Sascha Hauer,
Pengutronix Kernel Team, Fabio Estevam, imx, linux-arm-kernel
> In that case I would suggest introducing a flag so that the key
> can only be accessed through the keyring subsystem.
Do you mean CRYPTO_ALG_KERN_DRIVER_ONLY instead of CRYPTO_ALG_INTERNAL or something else?
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] crypto: mxs-dcp: Enable user-space access to AES with hardware-bound keys
2024-09-14 12:41 ` Tomas Paukrt
@ 2024-09-17 5:25 ` Herbert Xu
0 siblings, 0 replies; 6+ messages in thread
From: Herbert Xu @ 2024-09-17 5:25 UTC (permalink / raw)
To: Tomas Paukrt
Cc: linux-crypto, David S. Miller, Shawn Guo, Sascha Hauer,
Pengutronix Kernel Team, Fabio Estevam, imx, linux-arm-kernel
On Sat, Sep 14, 2024 at 02:41:23PM +0200, Tomas Paukrt wrote:
>
> Do you mean CRYPTO_ALG_KERN_DRIVER_ONLY instead of CRYPTO_ALG_INTERNAL or something else?
No I mean a new flag which forces af_alg to only use keys from
the keyring subsystem.
Cheers,
--
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
^ permalink raw reply [flat|nested] 6+ messages in thread
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2024-09-13 10:58 [PATCH] crypto: mxs-dcp: Enable user-space access to AES with hardware-bound keys Tomas Paukrt
2024-09-14 8:35 ` Herbert Xu
2024-09-14 11:32 ` Tomas Paukrt
2024-09-14 11:38 ` Herbert Xu
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2024-09-17 5:25 ` Herbert Xu
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