On Mon, 2019-01-21 at 17:59 +0800, Kairui Song wrote:
> This patch let kexec_file_load makes use of .platform keyring as fall
> back if it failed to verify a PE signed image against secondary or
> builtin key ring, make it possible to verify kernel image signed with
> preboot keys as well.
>
> This commit adds a VERIFY_USE_PLATFORM_KEYRING similar to previous
> VERIFY_USE_SECONDARY_KEYRING indicating that verify_pkcs7_signature
> should verify the signature using platform keyring. Also, decrease
> the error message log level when verification failed with -ENOKEY,
> so that if called tried multiple time with different keyring it
> won't generate extra noises.
>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxx>
Reviewed/Tested-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
> ---
> arch/x86/kernel/kexec-bzimage64.c | 13 ++++++++++---
> certs/system_keyring.c | 13 ++++++++++++-
> include/linux/verification.h | 1 +
> 3 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
> index 7d97e432cbbc..2c007abd3d40 100644
> --- a/arch/x86/kernel/kexec-bzimage64.c
> +++ b/arch/x86/kernel/kexec-bzimage64.c
> @@ -534,9 +534,16 @@ static int bzImage64_cleanup(void *loader_data)
> #ifdef CONFIG_KEXEC_BZIMAGE_VERIFY_SIG
> static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len)
> {
> - return verify_pefile_signature(kernel, kernel_len,
> - VERIFY_USE_SECONDARY_KEYRING,
> - VERIFYING_KEXEC_PE_SIGNATURE);
> + int ret;
> + ret = verify_pefile_signature(kernel, kernel_len,
> + VERIFY_USE_SECONDARY_KEYRING,
> + VERIFYING_KEXEC_PE_SIGNATURE);
> + if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) {
> + ret = verify_pefile_signature(kernel, kernel_len,
> + VERIFY_USE_PLATFORM_KEYRING,
> + VERIFYING_KEXEC_PE_SIGNATURE);
> + }
> + return ret;
> }
> #endif
>
> diff --git a/certs/system_keyring.c b/certs/system_keyring.c
> index 4690ef9cda8a..7085c286f4bd 100644
> --- a/certs/system_keyring.c
> +++ b/certs/system_keyring.c
> @@ -240,11 +240,22 @@ int verify_pkcs7_signature(const void *data, size_t len,
> #else
> trusted_keys = builtin_trusted_keys;
> #endif
> + } else if (trusted_keys == VERIFY_USE_PLATFORM_KEYRING) {
> +#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
> + trusted_keys = platform_trusted_keys;
> +#else
> + trusted_keys = NULL;
> +#endif
> + if (!trusted_keys) {
> + ret = -ENOKEY;
> + pr_devel("PKCS#7 platform keyring is not available\n");
> + goto error;
> + }
> }
> ret = pkcs7_validate_trust(pkcs7, trusted_keys);
> if (ret < 0) {
> if (ret == -ENOKEY)
> - pr_err("PKCS#7 signature not signed with a trusted key\n");
> + pr_devel("PKCS#7 signature not signed with a trusted key\n");
> goto error;
> }
>
> diff --git a/include/linux/verification.h b/include/linux/verification.h
> index cfa4730d607a..018fb5f13d44 100644
> --- a/include/linux/verification.h
> +++ b/include/linux/verification.h
> @@ -17,6 +17,7 @@
> * should be used.
> */
> #define VERIFY_USE_SECONDARY_KEYRING ((struct key *)1UL)
> +#define VERIFY_USE_PLATFORM_KEYRING ((struct key *)2UL)
>
> /*
> * The use to which an asymmetric key is being put.
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