On Mon, Apr 06, 2026 at 10:42:00PM -0400, Nayna Jain wrote: > > On 3/24/26 7:00 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. > > > > Traces, when actually needed, can be easily enabled by providing > > trusted.dyndbg='+p' in the kernel command-line. > > > > Cc: Srish Srinivasan <[email protected]> > > Reported-by: Nayna Jain <[email protected]> > > Closes: > > https://lore.kernel.org/all/[email protected]/ > > Signed-off-by: Jarkko Sakkinen <[email protected]> > > --- > > v2: > > - Implement for all trusted keys backends. > > - Add HAVE_TRUSTED_KEYS_DEBUG as it is a good practice despite full > > coverage. > > --- > > include/keys/trusted-type.h | 18 +++++------- > > security/keys/trusted-keys/Kconfig | 19 ++++++++++++ > > security/keys/trusted-keys/trusted_caam.c | 4 +-- > > security/keys/trusted-keys/trusted_tpm1.c | 36 +++++++++++------------ > > 4 files changed, 46 insertions(+), 31 deletions(-) > > > > diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h > > index 03527162613f..620a1f890b6b 100644 > > --- a/include/keys/trusted-type.h > > +++ b/include/keys/trusted-type.h > > @@ -83,18 +83,16 @@ struct trusted_key_source { > > extern struct key_type key_type_trusted; > > -#define TRUSTED_DEBUG 0 > > - > > -#if TRUSTED_DEBUG > > +#ifdef CONFIG_TRUSTED_KEYS_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); > > + 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..2ad9ba0e03f1 100644 > > --- a/security/keys/trusted-keys/Kconfig > > +++ b/security/keys/trusted-keys/Kconfig > > @@ -1,10 +1,25 @@ > > 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 keys backends and core code that support debug dumps > > + can opt-in that feature here. Dumps 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'. > > Would it be good idea to add an explicit note/warning: > > > NOTE: This option is intended for debugging purposes only. Do not enable on > production systems as debug output may expose sensitive cryptographic > material. > If you are unsure, say N. > > Apart from this, looks good to me. > > Reviewed-by: Nayna Jain <[email protected]>
Thank, I'll add your tag but would you mind quickly screening v3 again where I add "trusted.debug=0|1". And yes, your suggestion about extra warning makes sense. Let's make this safe as possible. Mistakes do happen... and then those measures pay off :-) BR, Jarkko
