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Merge patch series "rsa: fix dependency, rename and relocate RSASSA PSS symbols"

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Quentin Schulz <foss+uboot@0leil.net> says:

While historically signature verification is mostly done for FIT such
FIT_SIGNATURE dependency for signature algorithm makes sense, it isn't
the only kind of file we can verify signatures of. It can also be done
manually with rsa_verify_hash() with an embedded public key.

Considering the impacted code is guarded by RSA_VERIFY, let's make the
symbol depend on that otherwise selecting it without RSA_VERIFY won't do
anything. The FIT_SIGNATURE dependency wasn't also enough before as it
only implied RSA_VERIFY.

Then, simply relocate the RSA SSA PSS padding with the other RSA symbols
in lib/rsa instead of in boot/ and rename it to remove the mention to
FIT.

Finally, add the PSS padding wherever PKCS1.5 padding is specified as
one or the other can be used.

Link: https://lore.kernel.org/r/20251031-rsa-pss-always-v2-0-a29184ea064d@cherry.de
This commit is contained in:
Tom Rini
2025-11-11 14:53:33 -06:00
parent 4b46f98244 c50f6b11b3
commit 62e89de769
6 changed files with 42 additions and 48 deletions
Download Patch File Download Diff File Expand all files Collapse all files

62
boot/Kconfig
View File

@@ -134,13 +134,6 @@ config FIT_SIGNATURE_MAX_SIZE
device memory. Assure this size does not extend past expected storage
space.
config FIT_RSASSA_PSS
bool "Support rsassa-pss signature scheme of FIT image contents"
depends on FIT_SIGNATURE
help
Enable this to support the pss padding algorithm as described
in the rfc8017 (https://tools.ietf.org/html/rfc8017).
config FIT_CIPHER
bool "Enable ciphering data in a FIT uImages"
depends on DM
@@ -192,18 +185,6 @@ config SPL_FIT
select SPL_HASH
select SPL_OF_LIBFDT
config VPL_FIT
bool "Support Flattened Image Tree within VPL"
depends on VPL
select VPL_HASH
select VPL_OF_LIBFDT
config TPL_FIT
bool "Support Flattened Image Tree within TPL"
depends on TPL
select TPL_HASH
select TPL_OF_LIBFDT
config SPL_FIT_PRINT
bool "Support FIT printing within SPL"
depends on SPL_FIT
@@ -242,13 +223,6 @@ config SPL_FIT_SIGNATURE_MAX_SIZE
device memory. Assure this size does not extend past expected storage
space.
config SPL_FIT_RSASSA_PSS
bool "Support rsassa-pss signature scheme of FIT image contents in SPL"
depends on SPL_FIT_SIGNATURE
help
Enable this to support the pss padding algorithm as described
in the rfc8017 (https://tools.ietf.org/html/rfc8017) in SPL.
config SPL_LOAD_FIT
bool "Enable SPL loading U-Boot as a FIT (basic fitImage features)"
depends on SPL
@@ -309,6 +283,27 @@ config SPL_LOAD_FIT_FULL
particular it can handle selecting from multiple device tree
and passing the correct one to U-Boot.
config SPL_FIT_IMAGE_POST_PROCESS
bool "Enable post-processing of FIT artifacts after loading by the SPL"
depends on SPL_LOAD_FIT
default y if TI_SECURE_DEVICE
help
Allows doing any sort of manipulation to blobs after they got extracted
from the U-Boot FIT image like stripping off headers or modifying the
size of the blob, verification, authentication, decryption etc. in a
platform or board specific way. In order to use this feature a platform
or board-specific implementation of board_fit_image_post_process() must
be provided. Also, anything done during this post-processing step would
need to be comprehended in how the images were prepared before being
injected into the FIT creation (i.e. the blobs would have been pre-
processed before being added to the FIT image).
config TPL_FIT
bool "Support Flattened Image Tree within TPL"
depends on TPL
select TPL_HASH
select TPL_OF_LIBFDT
config TPL_LOAD_FIT
bool "Enable TPL loading U-Boot as a FIT (basic fitImage features)"
depends on TPL
@@ -331,21 +326,6 @@ config TPL_LOAD_FIT
3. FDTs are only loaded for images with an "os" property of "u-boot".
"linux" images are also supported with Falcon boot mode.
config SPL_FIT_IMAGE_POST_PROCESS
bool "Enable post-processing of FIT artifacts after loading by the SPL"
depends on SPL_LOAD_FIT
default y if TI_SECURE_DEVICE
help
Allows doing any sort of manipulation to blobs after they got extracted
from the U-Boot FIT image like stripping off headers or modifying the
size of the blob, verification, authentication, decryption etc. in a
platform or board specific way. In order to use this feature a platform
or board-specific implementation of board_fit_image_post_process() must
be provided. Also, anything done during this post-processing step would
need to be comprehended in how the images were prepared before being
injected into the FIT creation (i.e. the blobs would have been pre-
processed before being added to the FIT image).
if VPL
config VPL_FIT

2
configs/sandbox_defconfig
View File

@@ -18,7 +18,6 @@ CONFIG_EFI_CAPSULE_AUTHENTICATE=y
CONFIG_EFI_CAPSULE_CRT_FILE="board/sandbox/capsule_pub_key_good.crt"
CONFIG_BUTTON_CMD=y
CONFIG_FIT=y
CONFIG_FIT_RSASSA_PSS=y
CONFIG_FIT_CIPHER=y
CONFIG_FIT_VERBOSE=y
CONFIG_BOOTMETH_ANDROID=y
@@ -383,6 +382,7 @@ CONFIG_MBEDTLS_LIB=y
CONFIG_HKDF_MBEDTLS=y
CONFIG_ECDSA=y
CONFIG_ECDSA_VERIFY=y
CONFIG_RSASSA_PSS=y
CONFIG_TPM=y
CONFIG_ERRNO_STR=y
CONFIG_GETOPT=y

14
lib/rsa/Kconfig
View File

@@ -67,6 +67,20 @@ config SPL_RSA_VERIFY_WITH_PKEY
key properties will be calculated on the fly in verification code
in the SPL.
config RSASSA_PSS
bool "Support rsassa-pss signature scheme"
depends on RSA_VERIFY
help
Enable this to support the pss padding algorithm as described
in the rfc8017 (https://tools.ietf.org/html/rfc8017).
config SPL_RSASSA_PSS
bool "Support rsassa-pss signature scheme within SPL"
depends on SPL_RSA_VERIFY
help
Enable this to support the pss padding algorithm as described
in the rfc8017 (https://tools.ietf.org/html/rfc8017) within SPL.
config RSA_SOFTWARE_EXP
bool "Enable driver for RSA Modular Exponentiation in software"
depends on DM

2
lib/rsa/rsa-sign.c
View File

@@ -421,7 +421,7 @@ static int rsa_sign_with_key(EVP_PKEY *pkey, struct padding_algo *padding_algo,
goto err_sign;
}
if (CONFIG_IS_ENABLED(FIT_RSASSA_PSS) && padding_algo &&
if (CONFIG_IS_ENABLED(RSASSA_PSS) && padding_algo &&
!strcmp(padding_algo->name, "pss")) {
if (EVP_PKEY_CTX_set_rsa_padding(ckey,
RSA_PKCS1_PSS_PADDING) <= 0) {

8
lib/rsa/rsa-verify.c
View File

@@ -89,7 +89,7 @@ U_BOOT_PADDING_ALGO(pkcs_15) = {
};
#endif
#if CONFIG_IS_ENABLED(FIT_RSASSA_PSS)
#if CONFIG_IS_ENABLED(RSASSA_PSS)
static void u32_i2osp(uint32_t val, uint8_t *buf)
{
buf[0] = (uint8_t)((val >> 24) & 0xff);
@@ -310,7 +310,7 @@ U_BOOT_PADDING_ALGO(pss) = {
/**
* rsa_verify_key() - Verify a signature against some data using RSA Key
*
* Verify a RSA PKCS1.5 signature against an expected hash using
* Verify a RSA PKCS1.5/PSS signature against an expected hash using
* the RSA Key properties in prop structure.
*
* @info: Specifies key and FIT information
@@ -388,7 +388,7 @@ static int rsa_verify_key(struct image_sign_info *info,
* @sig_len: Number of bytes in signature
*
* Parse a RSA public key blob in DER format pointed to in @info and fill
* a key_prop structure with properties of the key. Then verify a RSA PKCS1.5
* a key_prop structure with properties of the key. Then verify a RSA PKCS1.5/PSS
* signature against an expected hash using the calculated properties.
*
* Return 0 if verified, -ve on error
@@ -423,7 +423,7 @@ int rsa_verify_with_pkey(struct image_sign_info *info,
* information in node with prperties of RSA Key like modulus, exponent etc.
*
* Parse sign-node and fill a key_prop structure with properties of the
* key. Verify a RSA PKCS1.5 signature against an expected hash using
* key. Verify a RSA PKCS1.5/PSS signature against an expected hash using
* the properties parsed
*
* @info: Specifies key and FIT information

2
tools/Kconfig
View File

@@ -55,7 +55,7 @@ config TOOLS_FIT_PRINT
help
Print the content of the FIT verbosely in the tools builds
config TOOLS_FIT_RSASSA_PSS
config TOOLS_RSASSA_PSS
def_bool y
help
Support the rsassa-pss signature scheme in the tools builds