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Hallyn" , Ahmad Fatoum , Pengutronix Kernel Team , Andrew Morton , "Borislav Petkov (AMD)" , Randy Dunlap , Dave Hansen , Pawan Gupta , Feng Tang , Dapeng Mi , Kees Cook , Marco Elver , Li RongQing , "Paul E. McKenney" , Thomas Gleixner , Bjorn Helgaas , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org References: <20260415111202.63888-1-jarkko@kernel.org> Content-Language: en-US From: Nayna Jain In-Reply-To: <20260415111202.63888-1-jarkko@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: KQs0K3VmyIOiiaAotl8jIaQj_pgOcwaG X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNDE2MDAyNCBTYWx0ZWRfX7jdsV3hJl25F wgNI/yzuVOIDxGsHByiCGYlO+b2RZJiYQQHpXqtPnP2l/PXX9yaxCsiwgZtNpB5gsGXKUGX5CdJ DByWXWoK8un5jrBw3448Z3/hJ4E5W9sY+BWFzaOZ7eAXNB0p6p9YOLqykZG9ITrV8Z10whGoP8s WSwacaQHprnFlBCR/CiCw06JdzlgQDBdRhvWmu3zvgSxlWzZhinTfeSZgFRFkaNYOMDc5nqxd9X YTWOez6IA+uAC/VGSFbheIULWPtTEdMzVe5rAT/fJmVrOdDaPM90HTOjSECwPUu+8WOZJNekMv9 nIOnGlo3NSR/rC/l3WU2vA7mbPp0aUxbXx9BH0gx0UDaLH969DhS6oslFnNJ7yuvbpClRjb8X2+ tRhBSXnVha8xyp3hN0OqYajyHt59KYAtETvyhr6BUylbVFbBmPZuFIGJa/LKu92NfJeDBTMUvyT PWA9gC+e8U75129cgvw== X-Proofpoint-ORIG-GUID: au-3_HIjGvpReuOQLMWnpLP-U0wEWjrm X-Authority-Analysis: v=2.4 cv=W60IkxWk c=1 sm=1 tr=0 ts=69e05494 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=zzKBsTiU_qEVFVDPJAMA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-04-16_01,2026-04-13_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 clxscore=1011 priorityscore=1501 spamscore=0 bulkscore=0 adultscore=0 phishscore=0 lowpriorityscore=0 suspectscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2604070000 definitions=main-2604160024 On 4/15/26 7:12 AM, Jarkko Sakkinen wrote: > TPM_DEBUG, and other similar flags, are a non-standard way to specify a > feature in Linux kernel. Introduce CONFIG_TRUSTED_KEYS_DEBUG for trusted > keys, and use it to replace these ad-hoc feature flags. > > Given that trusted keys debug dumps can contain sensitive data, harden the > feature as follows: > > 1. In the Kconfig description postulate that pr_debug() statements must be > used. > 2. Use pr_debug() statements in TPM 1.x driver to print the protocol dump. > 3. Require trusted.debug=1 on the kernel command line (default: 0) to > activate dumps at runtime, even when CONFIG_TRUSTED_KEYS_DEBUG=y. > > Traces, when actually needed, can be easily enabled by providing > trusted.dyndbg='+p' and trusted.debug=1 in the kernel command-line. Thanks for adding the documentation. Reviewed-by: Nayna Jain > > Reported-by: Nayna Jain > Closes: https://lore.kernel.org/all/7f8b8478-5cd8-4d97-bfd0-341fd5cf10f9@linux.ibm.com/ > Reviewed-by: Nayna Jain > Tested-by: Srish Srinivasan > Signed-off-by: Jarkko Sakkinen > --- > v4: > - Added kernel parameter documentation.t > - Added tags from Srishand and Nayna. > - Sanity check round. This version will be applied unless there is > something specific to address. > v3: > - Add kernel-command line option for enabling the traces. > - Add safety information to the Kconfig entry. > v2: > - Implement for all trusted keys backends. > - Add HAVE_TRUSTED_KEYS_DEBUG as it is a good practice despite full > coverage. > --- > .../admin-guide/kernel-parameters.txt | 16 +++++++ > include/keys/trusted-type.h | 21 +++++---- > security/keys/trusted-keys/Kconfig | 23 ++++++++++ > security/keys/trusted-keys/trusted_caam.c | 7 ++- > security/keys/trusted-keys/trusted_core.c | 6 +++ > security/keys/trusted-keys/trusted_tpm1.c | 44 +++++++++++-------- > 6 files changed, 87 insertions(+), 30 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index f2ce1f4975c1..f1515668c8ab 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -7917,6 +7917,22 @@ Kernel parameters > first trust source as a backend which is initialized > successfully during iteration. > > + trusted.debug= [KEYS] > + Format: > + Enable trusted keys debug traces at runtime when > + CONFIG_TRUSTED_KEYS_DEBUG=y. > + > + To make the traces visible after enabling the option, > + use trusted.dyndbg='+p' as needed. By convention, > + the subsystem uses pr_debug() for these traces. > + > + SAFETY: The traces can leak sensitive data, so be > + cautious before enabling this. They remain inactive > + unless this parameter is set this option to a true > + value. > + > + Default: false > + > trusted.rng= [KEYS] > Format: > The RNG used to generate key material for trusted keys. > diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h > index 03527162613f..9f9940482da4 100644 > --- a/include/keys/trusted-type.h > +++ b/include/keys/trusted-type.h > @@ -83,18 +83,21 @@ struct trusted_key_source { > > extern struct key_type key_type_trusted; > > -#define TRUSTED_DEBUG 0 > +#ifdef CONFIG_TRUSTED_KEYS_DEBUG > +extern bool trusted_debug; > > -#if TRUSTED_DEBUG > static inline void dump_payload(struct trusted_key_payload *p) > { > - pr_info("key_len %d\n", p->key_len); > - print_hex_dump(KERN_INFO, "key ", DUMP_PREFIX_NONE, > - 16, 1, p->key, p->key_len, 0); > - pr_info("bloblen %d\n", p->blob_len); > - print_hex_dump(KERN_INFO, "blob ", DUMP_PREFIX_NONE, > - 16, 1, p->blob, p->blob_len, 0); > - pr_info("migratable %d\n", p->migratable); > + if (!trusted_debug) > + return; > + > + pr_debug("key_len %d\n", p->key_len); > + print_hex_dump_debug("key ", DUMP_PREFIX_NONE, > + 16, 1, p->key, p->key_len, 0); > + pr_debug("bloblen %d\n", p->blob_len); > + print_hex_dump_debug("blob ", DUMP_PREFIX_NONE, > + 16, 1, p->blob, p->blob_len, 0); > + pr_debug("migratable %d\n", p->migratable); > } > #else > static inline void dump_payload(struct trusted_key_payload *p) > diff --git a/security/keys/trusted-keys/Kconfig b/security/keys/trusted-keys/Kconfig > index 9e00482d886a..e5a4a53aeab2 100644 > --- a/security/keys/trusted-keys/Kconfig > +++ b/security/keys/trusted-keys/Kconfig > @@ -1,10 +1,29 @@ > config HAVE_TRUSTED_KEYS > bool > > +config HAVE_TRUSTED_KEYS_DEBUG > + bool > + > +config TRUSTED_KEYS_DEBUG > + bool "Debug trusted keys" > + depends on HAVE_TRUSTED_KEYS_DEBUG > + default n > + help > + Trusted key backends and core code that support debug traces can > + opt-in that feature here. Traces must only use debug level output, as > + sensitive data may pass by. In the kernel-command line traces can be > + enabled via trusted.dyndbg='+p'. > + > + SAFETY: Debug dumps are inactive at runtime until trusted.debug is set > + to a true value on the kernel command-line. Use at your utmost > + consideration when enabling this feature on a production build. The > + general advice is not to do this. > + > config TRUSTED_KEYS_TPM > bool "TPM-based trusted keys" > depends on TCG_TPM >= TRUSTED_KEYS > default y > + select HAVE_TRUSTED_KEYS_DEBUG > select CRYPTO_HASH_INFO > select CRYPTO_LIB_SHA1 > select CRYPTO_LIB_UTILS > @@ -23,6 +42,7 @@ config TRUSTED_KEYS_TEE > bool "TEE-based trusted keys" > depends on TEE >= TRUSTED_KEYS > default y > + select HAVE_TRUSTED_KEYS_DEBUG > select HAVE_TRUSTED_KEYS > help > Enable use of the Trusted Execution Environment (TEE) as trusted > @@ -33,6 +53,7 @@ config TRUSTED_KEYS_CAAM > depends on CRYPTO_DEV_FSL_CAAM_JR >= TRUSTED_KEYS > select CRYPTO_DEV_FSL_CAAM_BLOB_GEN > default y > + select HAVE_TRUSTED_KEYS_DEBUG > select HAVE_TRUSTED_KEYS > help > Enable use of NXP's Cryptographic Accelerator and Assurance Module > @@ -42,6 +63,7 @@ config TRUSTED_KEYS_DCP > bool "DCP-based trusted keys" > depends on CRYPTO_DEV_MXS_DCP >= TRUSTED_KEYS > default y > + select HAVE_TRUSTED_KEYS_DEBUG > select HAVE_TRUSTED_KEYS > help > Enable use of NXP's DCP (Data Co-Processor) as trusted key backend. > @@ -50,6 +72,7 @@ config TRUSTED_KEYS_PKWM > bool "PKWM-based trusted keys" > depends on PSERIES_PLPKS >= TRUSTED_KEYS > default y > + select HAVE_TRUSTED_KEYS_DEBUG > select HAVE_TRUSTED_KEYS > help > Enable use of IBM PowerVM Key Wrapping Module (PKWM) as a trusted key backend. > diff --git a/security/keys/trusted-keys/trusted_caam.c b/security/keys/trusted-keys/trusted_caam.c > index 601943ce0d60..6a33dbf2a7f5 100644 > --- a/security/keys/trusted-keys/trusted_caam.c > +++ b/security/keys/trusted-keys/trusted_caam.c > @@ -28,10 +28,13 @@ static const match_table_t key_tokens = { > {opt_err, NULL} > }; > > -#ifdef CAAM_DEBUG > +#ifdef CONFIG_TRUSTED_KEYS_DEBUG > static inline void dump_options(const struct caam_pkey_info *pkey_info) > { > - pr_info("key encryption algo %d\n", pkey_info->key_enc_algo); > + if (!trusted_debug) > + return; > + > + pr_debug("key encryption algo %d\n", pkey_info->key_enc_algo); > } > #else > static inline void dump_options(const struct caam_pkey_info *pkey_info) > diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c > index 0b142d941cd2..6aed17bee09d 100644 > --- a/security/keys/trusted-keys/trusted_core.c > +++ b/security/keys/trusted-keys/trusted_core.c > @@ -31,6 +31,12 @@ static char *trusted_rng = "default"; > module_param_named(rng, trusted_rng, charp, 0); > MODULE_PARM_DESC(rng, "Select trusted key RNG"); > > +#ifdef CONFIG_TRUSTED_KEYS_DEBUG > +bool trusted_debug; > +module_param_named(debug, trusted_debug, bool, 0); > +MODULE_PARM_DESC(debug, "Enable trusted keys debug traces (default: 0)"); > +#endif > + > static char *trusted_key_source; > module_param_named(source, trusted_key_source, charp, 0); > MODULE_PARM_DESC(source, "Select trusted keys source (tpm, tee, caam, dcp or pkwm)"); > diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c > index 6ea728f1eae6..13513819991e 100644 > --- a/security/keys/trusted-keys/trusted_tpm1.c > +++ b/security/keys/trusted-keys/trusted_tpm1.c > @@ -46,38 +46,44 @@ enum { > SRK_keytype = 4 > }; > > -#define TPM_DEBUG 0 > - > -#if TPM_DEBUG > +#ifdef CONFIG_TRUSTED_KEYS_DEBUG > static inline void dump_options(struct trusted_key_options *o) > { > - pr_info("sealing key type %d\n", o->keytype); > - pr_info("sealing key handle %0X\n", o->keyhandle); > - pr_info("pcrlock %d\n", o->pcrlock); > - pr_info("pcrinfo %d\n", o->pcrinfo_len); > - print_hex_dump(KERN_INFO, "pcrinfo ", DUMP_PREFIX_NONE, > - 16, 1, o->pcrinfo, o->pcrinfo_len, 0); > + if (!trusted_debug) > + return; > + > + pr_debug("sealing key type %d\n", o->keytype); > + pr_debug("sealing key handle %0X\n", o->keyhandle); > + pr_debug("pcrlock %d\n", o->pcrlock); > + pr_debug("pcrinfo %d\n", o->pcrinfo_len); > + print_hex_dump_debug("pcrinfo ", DUMP_PREFIX_NONE, > + 16, 1, o->pcrinfo, o->pcrinfo_len, 0); > } > > static inline void dump_sess(struct osapsess *s) > { > - print_hex_dump(KERN_INFO, "trusted-key: handle ", DUMP_PREFIX_NONE, > - 16, 1, &s->handle, 4, 0); > - pr_info("secret:\n"); > - print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, > - 16, 1, &s->secret, SHA1_DIGEST_SIZE, 0); > - pr_info("trusted-key: enonce:\n"); > - print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, > - 16, 1, &s->enonce, SHA1_DIGEST_SIZE, 0); > + if (!trusted_debug) > + return; > + > + print_hex_dump_debug("trusted-key: handle ", DUMP_PREFIX_NONE, > + 16, 1, &s->handle, 4, 0); > + pr_debug("secret:\n"); > + print_hex_dump_debug("", DUMP_PREFIX_NONE, > + 16, 1, &s->secret, SHA1_DIGEST_SIZE, 0); > + pr_debug("trusted-key: enonce:\n"); > + print_hex_dump_debug("", DUMP_PREFIX_NONE, > + 16, 1, &s->enonce, SHA1_DIGEST_SIZE, 0); > } > > static inline void dump_tpm_buf(unsigned char *buf) > { > int len; > > - pr_info("\ntpm buffer\n"); > + if (!trusted_debug) > + return; > + pr_debug("\ntpm buffer\n"); > len = LOAD32(buf, TPM_SIZE_OFFSET); > - print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1, buf, len, 0); > + print_hex_dump_debug("", DUMP_PREFIX_NONE, 16, 1, buf, len, 0); > } > #else > static inline void dump_options(struct trusted_key_options *o)