diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-24 13:50:39 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-24 13:50:39 -0700 |
commit | 0350785b0a092c99c5ddd2ace0260dbe7b3f919f (patch) | |
tree | 3b9189b609f05d097f3ea9cb42c1a523308d53cb /security/integrity/ima/ima_appraise.c | |
parent | 7cf6a8a17f5b134b7e783c2d45c53298faef82a7 (diff) | |
parent | 048ae41bb0806cde340f4e5d5030398037ab0be8 (diff) |
Merge tag 'integrity-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull IMA updates from Mimi Zohar:
"New is IMA support for including fs-verity file digests and signatures
in the IMA measurement list as well as verifying the fs-verity file
digest based signatures, both based on policy.
In addition, are two bug fixes:
- avoid reading UEFI variables, which cause a page fault, on Apple
Macs with T2 chips.
- remove the original "ima" template Kconfig option to address a boot
command line ordering issue.
The rest is a mixture of code/documentation cleanup"
* tag 'integrity-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
integrity: Fix sparse warnings in keyring_handler
evm: Clean up some variables
evm: Return INTEGRITY_PASS for enum integrity_status value '0'
efi: Do not import certificates from UEFI Secure Boot for T2 Macs
fsverity: update the documentation
ima: support fs-verity file digest based version 3 signatures
ima: permit fsverity's file digests in the IMA measurement list
ima: define a new template field named 'd-ngv2' and templates
fs-verity: define a function to return the integrity protected file digest
ima: use IMA default hash algorithm for integrity violations
ima: fix 'd-ng' comments and documentation
ima: remove the IMA_TEMPLATE Kconfig option
ima: remove redundant initialization of pointer 'file'.
Diffstat (limited to 'security/integrity/ima/ima_appraise.c')
-rw-r--r-- | security/integrity/ima/ima_appraise.c | 114 |
1 files changed, 110 insertions, 4 deletions
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 17232bbfb9f9..cdb84dccd24e 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -13,7 +13,9 @@ #include <linux/magic.h> #include <linux/ima.h> #include <linux/evm.h> +#include <linux/fsverity.h> #include <keys/system_keyring.h> +#include <uapi/linux/fsverity.h> #include "ima.h" @@ -183,13 +185,18 @@ enum hash_algo ima_get_hash_algo(const struct evm_ima_xattr_data *xattr_value, return ima_hash_algo; switch (xattr_value->type) { + case IMA_VERITY_DIGSIG: + sig = (typeof(sig))xattr_value; + if (sig->version != 3 || xattr_len <= sizeof(*sig) || + sig->hash_algo >= HASH_ALGO__LAST) + return ima_hash_algo; + return sig->hash_algo; case EVM_IMA_XATTR_DIGSIG: sig = (typeof(sig))xattr_value; if (sig->version != 2 || xattr_len <= sizeof(*sig) || sig->hash_algo >= HASH_ALGO__LAST) return ima_hash_algo; return sig->hash_algo; - break; case IMA_XATTR_DIGEST_NG: /* first byte contains algorithm id */ ret = xattr_value->data[0]; @@ -226,6 +233,40 @@ int ima_read_xattr(struct dentry *dentry, } /* + * calc_file_id_hash - calculate the hash of the ima_file_id struct data + * @type: xattr type [enum evm_ima_xattr_type] + * @algo: hash algorithm [enum hash_algo] + * @digest: pointer to the digest to be hashed + * @hash: (out) pointer to the hash + * + * IMA signature version 3 disambiguates the data that is signed by + * indirectly signing the hash of the ima_file_id structure data. + * + * Signing the ima_file_id struct is currently only supported for + * IMA_VERITY_DIGSIG type xattrs. + * + * Return 0 on success, error code otherwise. + */ +static int calc_file_id_hash(enum evm_ima_xattr_type type, + enum hash_algo algo, const u8 *digest, + struct ima_digest_data *hash) +{ + struct ima_file_id file_id = { + .hash_type = IMA_VERITY_DIGSIG, .hash_algorithm = algo}; + unsigned int unused = HASH_MAX_DIGESTSIZE - hash_digest_size[algo]; + + if (type != IMA_VERITY_DIGSIG) + return -EINVAL; + + memcpy(file_id.hash, digest, hash_digest_size[algo]); + + hash->algo = algo; + hash->length = hash_digest_size[algo]; + + return ima_calc_buffer_hash(&file_id, sizeof(file_id) - unused, hash); +} + +/* * xattr_verify - verify xattr digest or signature * * Verify whether the hash or signature matches the file contents. @@ -236,7 +277,10 @@ static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint, struct evm_ima_xattr_data *xattr_value, int xattr_len, enum integrity_status *status, const char **cause) { + struct ima_max_digest_data hash; + struct signature_v2_hdr *sig; int rc = -EINVAL, hash_start = 0; + int mask; switch (xattr_value->type) { case IMA_XATTR_DIGEST_NG: @@ -246,7 +290,10 @@ static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint, case IMA_XATTR_DIGEST: if (*status != INTEGRITY_PASS_IMMUTABLE) { if (iint->flags & IMA_DIGSIG_REQUIRED) { - *cause = "IMA-signature-required"; + if (iint->flags & IMA_VERITY_REQUIRED) + *cause = "verity-signature-required"; + else + *cause = "IMA-signature-required"; *status = INTEGRITY_FAIL; break; } @@ -274,6 +321,20 @@ static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint, break; case EVM_IMA_XATTR_DIGSIG: set_bit(IMA_DIGSIG, &iint->atomic_flags); + + mask = IMA_DIGSIG_REQUIRED | IMA_VERITY_REQUIRED; + if ((iint->flags & mask) == mask) { + *cause = "verity-signature-required"; + *status = INTEGRITY_FAIL; + break; + } + + sig = (typeof(sig))xattr_value; + if (sig->version >= 3) { + *cause = "invalid-signature-version"; + *status = INTEGRITY_FAIL; + break; + } rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, (const char *)xattr_value, xattr_len, @@ -297,6 +358,44 @@ static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint, *status = INTEGRITY_PASS; } break; + case IMA_VERITY_DIGSIG: + set_bit(IMA_DIGSIG, &iint->atomic_flags); + + if (iint->flags & IMA_DIGSIG_REQUIRED) { + if (!(iint->flags & IMA_VERITY_REQUIRED)) { + *cause = "IMA-signature-required"; + *status = INTEGRITY_FAIL; + break; + } + } + + sig = (typeof(sig))xattr_value; + if (sig->version != 3) { + *cause = "invalid-signature-version"; + *status = INTEGRITY_FAIL; + break; + } + + rc = calc_file_id_hash(IMA_VERITY_DIGSIG, iint->ima_hash->algo, + iint->ima_hash->digest, &hash.hdr); + if (rc) { + *cause = "sigv3-hashing-error"; + *status = INTEGRITY_FAIL; + break; + } + + rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA, + (const char *)xattr_value, + xattr_len, hash.digest, + hash.hdr.length); + if (rc) { + *cause = "invalid-verity-signature"; + *status = INTEGRITY_FAIL; + } else { + *status = INTEGRITY_PASS; + } + + break; default: *status = INTEGRITY_UNKNOWN; *cause = "unknown-ima-data"; @@ -396,8 +495,15 @@ int ima_appraise_measurement(enum ima_hooks func, if (rc && rc != -ENODATA) goto out; - cause = iint->flags & IMA_DIGSIG_REQUIRED ? - "IMA-signature-required" : "missing-hash"; + if (iint->flags & IMA_DIGSIG_REQUIRED) { + if (iint->flags & IMA_VERITY_REQUIRED) + cause = "verity-signature-required"; + else + cause = "IMA-signature-required"; + } else { + cause = "missing-hash"; + } + status = INTEGRITY_NOLABEL; if (file->f_mode & FMODE_CREATED) iint->flags |= IMA_NEW_FILE; |