From: Roberto Sassu roberto.sassu@huawei.com
Introduce verify_uasym_signature() and verify_uasym_sig_message(), to verify user asymmetric key signatures from detached data. It aims to be used by kernel subsystems wishing to verify the authenticity of system data, with system-defined keyrings as trust anchor.
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com --- certs/system_keyring.c | 125 +++++++++++++++++++++++++++++++++++ include/linux/verification.h | 50 ++++++++++++++ 2 files changed, 175 insertions(+)
diff --git a/certs/system_keyring.c b/certs/system_keyring.c index a7a49b17ceb..dbee2e5b732 100644 --- a/certs/system_keyring.c +++ b/certs/system_keyring.c @@ -16,6 +16,7 @@ #include <keys/asymmetric-type.h> #include <keys/system_keyring.h> #include <crypto/pkcs7.h> +#include <crypto/uasym_keys_sigs.h>
static struct key *builtin_trusted_keys; #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING @@ -339,6 +340,130 @@ int verify_pkcs7_signature(const void *data, size_t len, } EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
+#ifdef CONFIG_UASYM_KEYS_SIGS +/** + * verify_uasym_sig_message - Verify a user asym key signature on system data + * @data: The data to be verified (must be provided) + * @len: Size of @data + * @uasym_sig: The signature context + * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, + * (void *)1UL for all trusted keys) + * (void *)2UL for platform keys) + * @usage: The use to which the key is being put + * @view_content: Callback to gain access to content + * @ctx: Context for callback + * + * Verify the user asymmetric key signature of the supplied system data, + * against a key (if found) in the supplied trusted keyring. + * + * Return: Zero on successful verification, a negative value otherwise. + */ +int verify_uasym_sig_message(const void *data, size_t len, + struct uasym_sig_message *uasym_sig, + struct key *trusted_keys, + enum key_being_used_for usage, + int (*view_content)(void *ctx, + const void *data, size_t len, + size_t asn1hdrlen), + void *ctx) +{ + int ret; + + /* The data should be detached - so we need to supply it. */ + if (data && uasym_sig_supply_detached_data(uasym_sig, data, len)) { + pr_err("Failed to supply data for user asymmetric key signature\n"); + ret = -EBADMSG; + goto error; + } + + if (!trusted_keys) { + trusted_keys = builtin_trusted_keys; + } else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) { +#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING + trusted_keys = secondary_trusted_keys; +#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("Platform keyring is not available\n"); + goto error; + } + } + + ret = uasym_sig_verify_message(uasym_sig, trusted_keys); + if (ret < 0) + goto error; + + if (view_content) { + size_t sig_data_len; + + ret = uasym_sig_get_content_data(uasym_sig, &data, &len, + &sig_data_len); + if (ret < 0) { + if (ret == -ENODATA) + pr_devel("User asymmetric key signature does not contain data\n"); + goto error; + } + + ret = view_content(ctx, data, len, sig_data_len); + kfree(data); + } +error: + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} +EXPORT_SYMBOL_GPL(verify_uasym_sig_message); + +/** + * verify_uasym_signature - Verify a user asym key signature on system data + * @data: The data to be verified (must be provided) + * @len: Size of @data + * @raw_uasym_sig: The raw signature + * @raw_uasym_sig_len: The size of @raw_uasym_sig + * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, + * (void *)1UL for all trusted keys) + * (void *)2UL for platform keys) + * @usage: The use to which the key is being put + * @view_content: Callback to gain access to content + * @ctx: Context for callback + * + * Verify the user asymmetric key signature of the supplied system data, + * against a key (if found) in the supplied trusted keyring. + * + * Return: Zero on successful verification, a negative value otherwise. + */ +int verify_uasym_signature(const void *data, size_t len, + const void *raw_uasym_sig, size_t raw_uasym_sig_len, + struct key *trusted_keys, + enum key_being_used_for usage, + int (*view_content)(void *ctx, + const void *data, size_t len, + size_t asn1hdrlen), + void *ctx) +{ + struct uasym_sig_message *uasym_sig; + int ret; + + uasym_sig = uasym_sig_parse_message(raw_uasym_sig, raw_uasym_sig_len); + if (IS_ERR(uasym_sig)) + return PTR_ERR(uasym_sig); + + ret = verify_uasym_sig_message(data, len, uasym_sig, trusted_keys, usage, + view_content, ctx); + + uasym_sig_free_message(uasym_sig); + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} +EXPORT_SYMBOL_GPL(verify_uasym_signature); +#endif /* CONFIG_UASYM_KEYS_SIGS */ #endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING diff --git a/include/linux/verification.h b/include/linux/verification.h index f34e50ebcf6..818f0ca4e12 100644 --- a/include/linux/verification.h +++ b/include/linux/verification.h @@ -43,6 +43,7 @@ extern const char *const key_being_used_for[NR__KEY_BEING_USED_FOR];
struct key; struct pkcs7_message; +struct uasym_sig_message;
extern int verify_pkcs7_signature(const void *data, size_t len, const void *raw_pkcs7, size_t pkcs7_len, @@ -62,6 +63,55 @@ extern int verify_pkcs7_message_sig(const void *data, size_t len, size_t asn1hdrlen), void *ctx);
+#ifdef CONFIG_UASYM_KEYS_SIGS +extern int verify_uasym_sig_message(const void *data, size_t len, + struct uasym_sig_message *uasym_sig, + struct key *trusted_keys, + enum key_being_used_for usage, + int (*view_content)(void *ctx, + const void *data, + size_t len, + size_t asn1hdrlen), + void *ctx); +extern int verify_uasym_signature(const void *data, size_t len, + const void *raw_uasym_sig, + size_t raw_uasym_sig_len, + struct key *trusted_keys, + enum key_being_used_for usage, + int (*view_content)(void *ctx, + const void *data, + size_t len, + size_t asn1hdrlen), + void *ctx); +#else +static inline int verify_uasym_sig_message(const void *data, size_t len, + struct uasym_sig_message *uasym_sig, + struct key *trusted_keys, + enum key_being_used_for usage, + int (*view_content)(void *ctx, + const void *data, + size_t len, + size_t asn1hdrlen), + void *ctx) +{ + return -EOPNOTSUPP; +} + +static inline int verify_uasym_signature(const void *data, size_t len, + const void *raw_uasym_sig, + size_t raw_uasym_sig_len, + struct key *trusted_keys, + enum key_being_used_for usage, + int (*view_content)(void *ctx, + const void *data, + size_t len, + size_t asn1hdrlen), + void *ctx) +{ + return -EOPNOTSUPP; +} +#endif /* CONFIG_UASYM_KEYS_SIGS */ + #ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION extern int verify_pefile_signature(const void *pebuf, unsigned pelen, struct key *trusted_keys,