From: Kairui Song kasong@redhat.com
This patch allows the kexec_file_load syscall to verify the PE signed kernel image signature based on the preboot keys stored in the .platform keyring, as fall back, if the signature verification failed due to not finding the public key in the secondary or builtin keyrings.
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@redhat.com Cc: David Howells dhowells@redhat.com Acked-by: Dave Young dyoung@redhat.com (for kexec_file_load part) [zohar@linux.ibm.com: tweaked the first paragraph of the patch description, and fixed checkpatch warning.] Signed-off-by: Mimi Zohar zohar@linux.ibm.com Signed-off-by: Zhang Tianxing zhangtianxing3@huawei.com --- arch/x86/kernel/kexec-bzimage64.c | 14 +++++++++++--- certs/system_keyring.c | 13 ++++++++++++- include/linux/verification.h | 1 + 3 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c index 70caa60b4c61..8977de5adb67 100644 --- a/arch/x86/kernel/kexec-bzimage64.c +++ b/arch/x86/kernel/kexec-bzimage64.c @@ -535,9 +535,17 @@ 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 da055e901df4..c05c29ae4d5d 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.