diff options
Diffstat (limited to 'debian/patches/features/all/db-mok-keyring/0003-MODSIGN-checking-the-blacklisted-hash-before-loading-a-kernel-module.patch')
| -rw-r--r-- | debian/patches/features/all/db-mok-keyring/0003-MODSIGN-checking-the-blacklisted-hash-before-loading-a-kernel-module.patch | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/debian/patches/features/all/db-mok-keyring/0003-MODSIGN-checking-the-blacklisted-hash-before-loading-a-kernel-module.patch b/debian/patches/features/all/db-mok-keyring/0003-MODSIGN-checking-the-blacklisted-hash-before-loading-a-kernel-module.patch new file mode 100644 index 000000000..f2278ce63 --- /dev/null +++ b/debian/patches/features/all/db-mok-keyring/0003-MODSIGN-checking-the-blacklisted-hash-before-loading-a-kernel-module.patch @@ -0,0 +1,130 @@ +From: "Lee, Chun-Yi" <joeyli.kernel@gmail.com> +Date: Tue, 13 Mar 2018 18:38:02 +0800 +Subject: [PATCH 3/4] MODSIGN: checking the blacklisted hash before loading a + kernel module +Origin: https://lore.kernel.org/patchwork/patch/933175/ + +This patch adds the logic for checking the kernel module's hash +base on blacklist. The hash must be generated by sha256 and enrolled +to dbx/mokx. + +For example: + sha256sum sample.ko + mokutil --mokx --import-hash $HASH_RESULT + +Whether the signature on ko file is stripped or not, the hash can be +compared by kernel. + +Cc: David Howells <dhowells@redhat.com> +Cc: Josh Boyer <jwboyer@fedoraproject.org> +Cc: James Bottomley <James.Bottomley@HansenPartnership.com> +Signed-off-by: "Lee, Chun-Yi" <jlee@suse.com> +[Rebased by Luca Boccassi] +[bwh: Forward-ported to 5.19: + - The type parameter to is_hash_blacklisted() is now an enumeration + rather than a string + - Adjust filename, context] +--- + kernel/module/signing.c | 59 +++++++++++++++++++++++++++++++++++++++-- + 1 file changed, 57 insertions(+), 2 deletions(-) + +--- a/kernel/module/signing.c ++++ b/kernel/module/signing.c +@@ -13,6 +13,8 @@ + #include <linux/verification.h> + #include <linux/security.h> + #include <crypto/public_key.h> ++#include <crypto/hash.h> ++#include <keys/system_keyring.h> + #include <uapi/linux/module.h> + #include "internal.h" + +@@ -37,13 +39,60 @@ + sig_enforce = true; + } + ++static int mod_is_hash_blacklisted(const void *mod, size_t verifylen) ++{ ++ struct crypto_shash *tfm; ++ struct shash_desc *desc; ++ size_t digest_size, desc_size; ++ u8 *digest; ++ int ret; ++ ++ tfm = crypto_alloc_shash("sha256", 0, 0); ++ if (IS_ERR(tfm)) { ++ ret = PTR_ERR(tfm); ++ goto error_return; ++ } ++ ++ desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); ++ digest_size = crypto_shash_digestsize(tfm); ++ digest = kzalloc(digest_size + desc_size, GFP_KERNEL); ++ if (!digest) { ++ pr_err("digest memory buffer allocate fail\n"); ++ ret = -ENOMEM; ++ goto error_digest; ++ } ++ desc = (void *)digest + digest_size; ++ desc->tfm = tfm; ++ ret = crypto_shash_init(desc); ++ if (ret < 0) ++ goto error_shash; ++ ++ ret = crypto_shash_finup(desc, mod, verifylen, digest); ++ if (ret < 0) ++ goto error_shash; ++ ++ pr_debug("%ld digest: %*phN\n", verifylen, (int) digest_size, digest); ++ ++ ret = is_hash_blacklisted(digest, digest_size, BLACKLIST_HASH_BINARY); ++ if (ret == -EKEYREJECTED) ++ pr_err("Module hash %*phN is blacklisted\n", ++ (int) digest_size, digest); ++ ++error_shash: ++ kfree(digest); ++error_digest: ++ crypto_free_shash(tfm); ++error_return: ++ return ret; ++} ++ + /* + * Verify the signature on a module. + */ + int mod_verify_sig(const void *mod, struct load_info *info) + { + struct module_signature ms; +- size_t sig_len, modlen = info->len; ++ size_t sig_len, modlen = info->len, wholelen; + int ret; + + pr_devel("==>%s(,%zu)\n", __func__, modlen); +@@ -51,6 +100,7 @@ + if (modlen <= sizeof(ms)) + return -EBADMSG; + ++ wholelen = modlen + sizeof(MODULE_SIG_STRING) - 1; + memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms)); + + ret = mod_check_sig(&ms, modlen, "module"); +@@ -61,10 +111,17 @@ + modlen -= sig_len + sizeof(ms); + info->len = modlen; + +- return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len, ++ ret = verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len, + VERIFY_USE_SECONDARY_KEYRING, + VERIFYING_MODULE_SIGNATURE, + NULL, NULL); ++ pr_devel("verify_pkcs7_signature() = %d\n", ret); ++ ++ /* checking hash of module is in blacklist */ ++ if (!ret) ++ ret = mod_is_hash_blacklisted(mod, wholelen); ++ ++ return ret; + } + + int module_sig_check(struct load_info *info, int flags) |