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| author | Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> | 2018-03-15 17:33:42 -0300 |
|---|---|---|
| committer | Mimi Zohar <zohar@linux.vnet.ibm.com> | 2018-03-25 07:26:30 -0400 |
| commit | f5e51fa368fd6612608bc36f39e55cde08ce0039 (patch) | |
| tree | 756645114becbeb4be95807b492d5c9ce35a82c8 /security | |
| parent | 1775cb87b063cd60a5021c38412f6024f93cc376 (diff) | |
| download | linux-f5e51fa368fd6612608bc36f39e55cde08ce0039.tar.gz linux-f5e51fa368fd6612608bc36f39e55cde08ce0039.tar.bz2 linux-f5e51fa368fd6612608bc36f39e55cde08ce0039.zip | |
ima: Improvements in ima_appraise_measurement()
Replace nested ifs in the EVM xattr verification logic with a switch
statement, making the code easier to understand.
Also, add comments to the if statements in the out section and constify the
cause variable.
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/integrity/ima/ima_appraise.c | 35 |
1 files changed, 22 insertions, 13 deletions
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c index 0c5f94b7b9c3..8bd7a0733e51 100644 --- a/security/integrity/ima/ima_appraise.c +++ b/security/integrity/ima/ima_appraise.c @@ -215,7 +215,7 @@ int ima_appraise_measurement(enum ima_hooks func, int xattr_len, int opened) { static const char op[] = "appraise_data"; - char *cause = "unknown"; + const char *cause = "unknown"; struct dentry *dentry = file_dentry(file); struct inode *inode = d_backing_inode(dentry); enum integrity_status status = INTEGRITY_UNKNOWN; @@ -241,16 +241,22 @@ int ima_appraise_measurement(enum ima_hooks func, } status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint); - if ((status != INTEGRITY_PASS) && - (status != INTEGRITY_PASS_IMMUTABLE) && - (status != INTEGRITY_UNKNOWN)) { - if ((status == INTEGRITY_NOLABEL) - || (status == INTEGRITY_NOXATTRS)) - cause = "missing-HMAC"; - else if (status == INTEGRITY_FAIL) - cause = "invalid-HMAC"; + switch (status) { + case INTEGRITY_PASS: + case INTEGRITY_PASS_IMMUTABLE: + case INTEGRITY_UNKNOWN: + break; + case INTEGRITY_NOXATTRS: /* No EVM protected xattrs. */ + case INTEGRITY_NOLABEL: /* No security.evm xattr. */ + cause = "missing-HMAC"; + goto out; + case INTEGRITY_FAIL: /* Invalid HMAC/signature. */ + cause = "invalid-HMAC"; goto out; + default: + WARN_ONCE(true, "Unexpected integrity status %d\n", status); } + switch (xattr_value->type) { case IMA_XATTR_DIGEST_NG: /* first byte contains algorithm id */ @@ -316,17 +322,20 @@ out: integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, op, cause, rc, 0); } else if (status != INTEGRITY_PASS) { + /* Fix mode, but don't replace file signatures. */ if ((ima_appraise & IMA_APPRAISE_FIX) && (!xattr_value || xattr_value->type != EVM_IMA_XATTR_DIGSIG)) { if (!ima_fix_xattr(dentry, iint)) status = INTEGRITY_PASS; - } else if ((inode->i_size == 0) && - (iint->flags & IMA_NEW_FILE) && - (xattr_value && - xattr_value->type == EVM_IMA_XATTR_DIGSIG)) { + } + + /* Permit new files with file signatures, but without data. */ + if (inode->i_size == 0 && iint->flags & IMA_NEW_FILE && + xattr_value && xattr_value->type == EVM_IMA_XATTR_DIGSIG) { status = INTEGRITY_PASS; } + integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, op, cause, rc, 0); } else { |