4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mimi Zohar zohar@linux.vnet.ibm.com
commit f3cc6b25dcc5616f0d5c720009b2ac66f97df2ff upstream.
All files matching a "measure" rule must be included in the IMA measurement list, even when the file hash cannot be calculated. Similarly, all files matching an "audit" rule must be audited, even when the file hash can not be calculated.
The file data hash field contained in the IMA measurement list template data will contain 0's instead of the actual file hash digest.
Note: In general, adding, deleting or in anyway changing which files are included in the IMA measurement list is not a good idea, as it might result in not being able to unseal trusted keys sealed to a specific TPM PCR value. This patch not only adds file measurements that were not previously measured, but specifies that the file hash value for these files will be 0's.
As the IMA measurement list ordering is not consistent from one boot to the next, it is unlikely that anyone is sealing keys based on the IMA measurement list. Remote attestation servers should be able to process these new measurement records, but might complain about these unknown records.
Signed-off-by: Mimi Zohar zohar@linux.vnet.ibm.com Reviewed-by: Dmitry Kasatkin dmitry.kasatkin@huawei.com Cc: Aditya Kali adityakali@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- security/integrity/ima/ima_api.c | 69 ++++++++++++++++++++++-------------- security/integrity/ima/ima_crypto.c | 10 +++++ security/integrity/ima/ima_main.c | 9 ++-- 3 files changed, 57 insertions(+), 31 deletions(-)
--- a/security/integrity/ima/ima_api.c +++ b/security/integrity/ima/ima_api.c @@ -198,42 +198,59 @@ int ima_collect_measurement(struct integ struct inode *inode = file_inode(file); const char *filename = file->f_path.dentry->d_name.name; int result = 0; + int length; + void *tmpbuf; + u64 i_version; struct { struct ima_digest_data hdr; char digest[IMA_MAX_DIGEST_SIZE]; } hash;
- if (!(iint->flags & IMA_COLLECTED)) { - u64 i_version = file_inode(file)->i_version; + if (iint->flags & IMA_COLLECTED) + goto out;
- if (file->f_flags & O_DIRECT) { - audit_cause = "failed(directio)"; - result = -EACCES; - goto out; - } - - hash.hdr.algo = algo; - - result = (!buf) ? ima_calc_file_hash(file, &hash.hdr) : - ima_calc_buffer_hash(buf, size, &hash.hdr); - if (!result) { - int length = sizeof(hash.hdr) + hash.hdr.length; - void *tmpbuf = krealloc(iint->ima_hash, length, - GFP_NOFS); - if (tmpbuf) { - iint->ima_hash = tmpbuf; - memcpy(iint->ima_hash, &hash, length); - iint->version = i_version; - iint->flags |= IMA_COLLECTED; - } else - result = -ENOMEM; - } + /* + * Dectecting file change is based on i_version. On filesystems + * which do not support i_version, support is limited to an initial + * measurement/appraisal/audit. + */ + i_version = file_inode(file)->i_version; + hash.hdr.algo = algo; + + /* Initialize hash digest to 0's in case of failure */ + memset(&hash.digest, 0, sizeof(hash.digest)); + + if (buf) + result = ima_calc_buffer_hash(buf, size, &hash.hdr); + else + result = ima_calc_file_hash(file, &hash.hdr); + + if (result && result != -EBADF && result != -EINVAL) + goto out; + + length = sizeof(hash.hdr) + hash.hdr.length; + tmpbuf = krealloc(iint->ima_hash, length, GFP_NOFS); + if (!tmpbuf) { + result = -ENOMEM; + goto out; } + + iint->ima_hash = tmpbuf; + memcpy(iint->ima_hash, &hash, length); + iint->version = i_version; + + /* Possibly temporary failure due to type of read (eg. O_DIRECT) */ + if (!result) + iint->flags |= IMA_COLLECTED; out: - if (result) + if (result) { + if (file->f_flags & O_DIRECT) + audit_cause = "failed(directio)"; + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, "collect_data", audit_cause, result, 0); + } return result; }
@@ -277,7 +294,7 @@ void ima_store_measurement(struct integr }
result = ima_store_template(entry, violation, inode, filename, pcr); - if (!result || result == -EEXIST) { + if ((!result || result == -EEXIST) && !(file->f_flags & O_DIRECT)) { iint->flags |= IMA_MEASURED; iint->measured_pcrs |= (0x1 << pcr); } --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -443,6 +443,16 @@ int ima_calc_file_hash(struct file *file loff_t i_size; int rc;
+ /* + * For consistency, fail file's opened with the O_DIRECT flag on + * filesystems mounted with/without DAX option. + */ + if (file->f_flags & O_DIRECT) { + hash->length = hash_digest_size[ima_hash_algo]; + hash->algo = ima_hash_algo; + return -EINVAL; + } + i_size = i_size_read(file_inode(file));
if (ima_ahash_minsize && i_size >= ima_ahash_minsize) { --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -242,11 +242,8 @@ static int process_measurement(struct fi hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
rc = ima_collect_measurement(iint, file, buf, size, hash_algo); - if (rc != 0) { - if (file->f_flags & O_DIRECT) - rc = (iint->flags & IMA_PERMIT_DIRECTIO) ? 0 : -EACCES; + if (rc != 0 && rc != -EBADF && rc != -EINVAL) goto out_digsig; - }
if (!pathbuf) /* ima_rdwr_violation possibly pre-fetched */ pathname = ima_d_path(&file->f_path, &pathbuf, filename); @@ -254,12 +251,14 @@ static int process_measurement(struct fi if (action & IMA_MEASURE) ima_store_measurement(iint, file, pathname, xattr_value, xattr_len, pcr); - if (action & IMA_APPRAISE_SUBMASK) + if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) rc = ima_appraise_measurement(func, iint, file, pathname, xattr_value, xattr_len, opened); if (action & IMA_AUDIT) ima_audit_measurement(iint, pathname);
+ if ((file->f_flags & O_DIRECT) && (iint->flags & IMA_PERMIT_DIRECTIO)) + rc = 0; out_digsig: if ((mask & MAY_WRITE) && (iint->flags & IMA_DIGSIG) && !(iint->flags & IMA_NEW_FILE))