9021469716

Committed 09 May 2024 06:01PM UTC coverage: 62.632% (+0.4%) from 62.281%

Build # 9021469716

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Pull #1304

github

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web-flow

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Merge c3449b504 into 7e4af5e33

Pull Request Pull Request #1304: Update SNTPolicyProcessor to use a map

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/Source/santad/SNTPolicyProcessor.mm

/// Copyright 2015 Google Inc. All rights reserved.
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///    http://www.apache.org/licenses/LICENSE-2.0
///
///    Unless required by applicable law or agreed to in writing, software
///    distributed under the License is distributed on an "AS IS" BASIS,
///    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
///    See the License for the specific language governing permissions and
///    limitations under the License.

#import "Source/santad/SNTPolicyProcessor.h"
#include <Foundation/Foundation.h>

#include <Kernel/kern/cs_blobs.h>
#import <MOLCodesignChecker/MOLCodesignChecker.h>
#import <Security/SecCode.h>
#import <Security/Security.h>

#import "Source/common/SNTCachedDecision.h"
#import "Source/common/SNTConfigurator.h"
#import "Source/common/SNTDeepCopy.h"
#import "Source/common/SNTFileInfo.h"
#import "Source/common/SNTLogging.h"
#import "Source/common/SNTRule.h"
#import "Source/santad/DataLayer/SNTRuleTable.h"
#include "absl/container/flat_hash_map.h"

@interface SNTPolicyProcessor ()
@property SNTRuleTable *ruleTable;
@property SNTConfigurator *configurator;
@end

@implementation SNTPolicyProcessor

- (instancetype)initWithRuleTable:(SNTRuleTable *)ruleTable {
  self = [super init];
  if (self) {
    _ruleTable = ruleTable;
    _configurator = [SNTConfigurator configurator];
  }
  return self;
}

// This method applies the rules to the cached decision object.
//
// It returns YES if the decision was made, NO if the decision was not made.
- (BOOL)decision:(SNTCachedDecision *)cd
              forRule:(SNTRule *)rule
  withTransitiveRules:(BOOL)enableTransitiveRules {
  static const auto decisions =
    absl::flat_hash_map<std::pair<SNTRuleType, SNTRuleState>, SNTEventState>{
      {{SNTRuleTypeCDHash, SNTRuleStateAllow}, SNTEventStateAllowCDHash},
      {{SNTRuleTypeCDHash, SNTRuleStateAllowCompiler}, SNTEventStateAllowCompiler},
      {{SNTRuleTypeCDHash, SNTRuleStateBlock}, SNTEventStateBlockCDHash},
      {{SNTRuleTypeCDHash, SNTRuleStateSilentBlock}, SNTEventStateBlockCDHash},
      {{SNTRuleTypeBinary, SNTRuleStateAllow}, SNTEventStateAllowBinary},
      {{SNTRuleTypeBinary, SNTRuleStateAllowTransitive}, SNTEventStateAllowTransitive},
      {{SNTRuleTypeBinary, SNTRuleStateAllowCompiler}, SNTEventStateAllowCompiler},
      {{SNTRuleTypeBinary, SNTRuleStateSilentBlock}, SNTEventStateBlockBinary},
      {{SNTRuleTypeBinary, SNTRuleStateBlock}, SNTEventStateBlockBinary},
      {{SNTRuleTypeSigningID, SNTRuleStateAllow}, SNTEventStateAllowSigningID},
      {{SNTRuleTypeSigningID, SNTRuleStateAllowCompiler}, SNTEventStateAllowCompiler},
      {{SNTRuleTypeSigningID, SNTRuleStateSilentBlock}, SNTEventStateBlockSigningID},
      {{SNTRuleTypeSigningID, SNTRuleStateBlock}, SNTEventStateBlockSigningID},
      {{SNTRuleTypeCertificate, SNTRuleStateAllow}, SNTEventStateAllowCertificate},
      {{SNTRuleTypeCertificate, SNTRuleStateSilentBlock}, SNTEventStateBlockCertificate},
      {{SNTRuleTypeCertificate, SNTRuleStateBlock}, SNTEventStateBlockCertificate},
      {{SNTRuleTypeTeamID, SNTRuleStateAllow}, SNTEventStateAllowTeamID},
      {{SNTRuleTypeTeamID, SNTRuleStateSilentBlock}, SNTEventStateBlockTeamID},
      {{SNTRuleTypeTeamID, SNTRuleStateBlock}, SNTEventStateBlockTeamID},
    };

  auto iterator = decisions.find(std::pair<SNTRuleType, SNTRuleState>{rule.type, rule.state});
  if (iterator != decisions.end()) {
    cd.decision = iterator->second;
  } else {
    // If we have an invalid state combination then either we have stale data in
    // the database or a programming error. We treat this as if the
    // corresponding rule was not found.
    LOGE(@"Invalid rule type/state combination %ld/%ld", rule.type, rule.state);
    return NO;
  }

  switch (rule.state) {
    case SNTRuleStateSilentBlock: cd.silentBlock = YES; break;
    case SNTRuleStateAllowCompiler:
      if (!enableTransitiveRules) {
        switch (rule.type) {
          case SNTRuleTypeCDHash: cd.decision = SNTEventStateAllowCDHash; break;
          case SNTRuleTypeBinary: cd.decision = SNTEventStateAllowBinary; break;
          case SNTRuleTypeSigningID: cd.decision = SNTEventStateAllowSigningID; break;
          default:
            // Programming error. Something's marked as a compiler that shouldn't
            // be.
            LOGE(@"Invalid compiler rule type %ld", rule.type);
            [NSException
               raise:@"Invalid compiler rule type"
              format:@"decision:forRule:withTransitiveRules: Unexpected compiler rule type: %ld",
                     rule.type];
            break;
        }
      }
      break;
    case SNTRuleStateAllowTransitive:
      // If transitive rules are disabled, then we treat
      // SNTRuleStateAllowTransitive rules as if a matching rule was not found
      // and set the state to unknown. Otherwise the decision map will have already set
      // the EventState to SNTEventStateAllowTransitive.
      if (!enableTransitiveRules) {
        cd.decision = SNTEventStateUnknown;
        return NO;
      }
      break;
    default:
      // If its not one of the special cases above, we don't need to do anything.
      break;
  }

  // We know we have a match so apply the custom messages
  cd.customMsg = rule.customMsg;
  cd.customURL = rule.customURL;

  return YES;
}

static void UpdateCachedDecisionSigningInfo(
  SNTCachedDecision *cd, MOLCodesignChecker *csInfo,
  NSDictionary *_Nullable (^entitlementsFilterCallback)(NSDictionary *_Nullable entitlements)) {
  cd.certSHA256 = csInfo.leafCertificate.SHA256;
  cd.certCommonName = csInfo.leafCertificate.commonName;
  cd.certChain = csInfo.certificates;
  // Check if we need to get teamID from code signing.
  if (!cd.teamID) {
    cd.teamID = csInfo.teamID;
  }

  // Ensure that if no teamID exists that the signing info confirms it is a
  // platform binary. If not, remove the signingID.
  if (!cd.teamID && cd.signingID) {
    if (!csInfo.platformBinary) {
      cd.signingID = nil;
    }
  }

  NSDictionary *entitlements = csInfo.entitlements;

  if (entitlementsFilterCallback) {
    cd.entitlements = entitlementsFilterCallback(entitlements);
    cd.entitlementsFiltered = (cd.entitlements.count != entitlements.count);
  } else {
    cd.entitlements = [entitlements sntDeepCopy];
    cd.entitlementsFiltered = NO;
  }
}

- (nonnull SNTCachedDecision *)decisionForFileInfo:(nonnull SNTFileInfo *)fileInfo
                                            cdhash:(nullable NSString *)cdhash
                                        fileSHA256:(nullable NSString *)fileSHA256
                                 certificateSHA256:(nullable NSString *)certificateSHA256
                                            teamID:(nullable NSString *)teamID
                                         signingID:(nullable NSString *)signingID
                              isProdSignedCallback:(BOOL (^_Nonnull)())isProdSignedCallback
                        entitlementsFilterCallback:
                          (NSDictionary *_Nullable (^_Nullable)(
                            NSDictionary *_Nullable entitlements))entitlementsFilterCallback {
  // Check the hash before allocating a SNTCachedDecision.
  NSString *fileHash = fileSHA256 ?: fileInfo.SHA256;
  SNTClientMode mode = [self.configurator clientMode];

  // If the binary is a critical system binary, don't check its signature.
  // The binary was validated at startup when the rule table was initialized.
  SNTCachedDecision *systemCd = self.ruleTable.criticalSystemBinaries[fileHash];
  if (systemCd) {
    systemCd.decisionClientMode = mode;
    return systemCd;
  }

  // Allocate a new cached decision for the execution.
  SNTCachedDecision *cd = [[SNTCachedDecision alloc] init];
  cd.cdhash = cdhash;
  cd.sha256 = fileHash;
  cd.teamID = teamID;
  cd.signingID = signingID;
  cd.decisionClientMode = mode;
  cd.quarantineURL = fileInfo.quarantineDataURL;

  NSError *csInfoError;
  if (certificateSHA256.length) {
    cd.certSHA256 = certificateSHA256;
  } else {
    // Grab the code signature, if there's an error don't try to capture
    // any of the signature details. Also clear out any rule lookup parameters
    // that would require being validly signed.
    MOLCodesignChecker *csInfo = [fileInfo codesignCheckerWithError:&csInfoError];
    if (csInfoError) {
      csInfo = nil;
      cd.decisionExtra =
        [NSString stringWithFormat:@"Signature ignored due to error: %ld", (long)csInfoError.code];
      cd.teamID = nil;
      cd.signingID = nil;
      cd.cdhash = nil;
    } else {
      UpdateCachedDecisionSigningInfo(cd, csInfo, entitlementsFilterCallback);
    }
  }

  // Do not evaluate TeamID/SigningID rules for dev-signed code based on the
  // assumption that orgs are generally more relaxed about dev signed cert
  // protections and users can more easily produce dev-signed code that
  // would otherwise be inadvertently allowed.
  // Note: Only perform the check if the SigningID is still set, otherwise
  // it is unsigned or had issues above that already cleared the values.
  if (cd.signingID && !isProdSignedCallback()) {
    LOGD(@"Ignoring TeamID and SigningID rules for code not signed with production cert: %@",
         cd.signingID);
    cd.teamID = nil;
    cd.signingID = nil;
  }

  SNTRule *rule =
    [self.ruleTable ruleForIdentifiers:(struct RuleIdentifiers){.cdhash = cd.cdhash,
                                                                .binarySHA256 = cd.sha256,
                                                                .signingID = cd.signingID,
                                                                .certificateSHA256 = cd.certSHA256,
                                                                .teamID = cd.teamID}];
  if (rule) {
    // If we have a rule match we don't need to process any further.
    if ([self decision:cd
                      forRule:rule
          withTransitiveRules:self.configurator.enableTransitiveRules]) {
      return cd;
    }
  }

  if ([[SNTConfigurator configurator] enableBadSignatureProtection] && csInfoError &&
      csInfoError.code != errSecCSUnsigned) {
    cd.decisionExtra =
      [NSString stringWithFormat:@"Blocked due to signature error: %ld", (long)csInfoError.code];
    cd.decision = SNTEventStateBlockCertificate;
    return cd;
  }

  NSString *msg = [self fileIsScopeBlocked:fileInfo];
  if (msg) {
    cd.decisionExtra = msg;
    cd.decision = SNTEventStateBlockScope;
    return cd;
  }

  msg = [self fileIsScopeAllowed:fileInfo];
  if (msg) {
    cd.decisionExtra = msg;
    cd.decision = SNTEventStateAllowScope;
    return cd;
  }

  switch (mode) {
    case SNTClientModeMonitor: cd.decision = SNTEventStateAllowUnknown; return cd;
    case SNTClientModeLockdown: cd.decision = SNTEventStateBlockUnknown; return cd;
    default: cd.decision = SNTEventStateBlockUnknown; return cd;
  }
}

- (nonnull SNTCachedDecision *)decisionForFileInfo:(nonnull SNTFileInfo *)fileInfo
                                     targetProcess:(nonnull const es_process_t *)targetProc
                        entitlementsFilterCallback:
                          (NSDictionary *_Nullable (^_Nonnull)(
                            const char *_Nullable teamID,
                            NSDictionary *_Nullable entitlements))entitlementsFilterCallback {
  NSString *signingID;
  NSString *teamID;
  NSString *cdhash;

  const char *entitlementsFilterTeamID = NULL;

  if (targetProc->codesigning_flags & CS_SIGNED && targetProc->codesigning_flags & CS_VALID) {
    if (targetProc->signing_id.length > 0) {
      if (targetProc->team_id.length > 0) {
        entitlementsFilterTeamID = targetProc->team_id.data;
        teamID = [NSString stringWithUTF8String:targetProc->team_id.data];
        signingID =
          [NSString stringWithFormat:@"%@:%@", teamID,
                                     [NSString stringWithUTF8String:targetProc->signing_id.data]];
      } else if (targetProc->is_platform_binary) {
        entitlementsFilterTeamID = "platform";
        signingID =
          [NSString stringWithFormat:@"platform:%@",
                                     [NSString stringWithUTF8String:targetProc->signing_id.data]];
      }
    }

    // Only consider the CDHash for processes that have CS_KILL or CS_HARD set.
    // This ensures that the OS will kill the process if the CDHash was tampered
    // with and code was loaded that didn't match a page hash.
    if (targetProc->codesigning_flags & CS_KILL || targetProc->codesigning_flags & CS_HARD) {
      static NSString *const kCDHashFormatString = @"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x"
                                                    "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x";

      const uint8_t *buf = targetProc->cdhash;
      cdhash = [[NSString alloc] initWithFormat:kCDHashFormatString, buf[0], buf[1], buf[2], buf[3],
                                                buf[4], buf[5], buf[6], buf[7], buf[8], buf[9],
                                                buf[10], buf[11], buf[12], buf[13], buf[14],
                                                buf[15], buf[16], buf[17], buf[18], buf[19]];
    }
  }

  return [self decisionForFileInfo:fileInfo
    cdhash:cdhash
    fileSHA256:nil
    certificateSHA256:nil
    teamID:teamID
    signingID:signingID
    isProdSignedCallback:^BOOL {
      return ((targetProc->codesigning_flags & CS_DEV_CODE) == 0);
    }
    entitlementsFilterCallback:^NSDictionary *(NSDictionary *entitlements) {
      return entitlementsFilterCallback(entitlementsFilterTeamID, entitlements);
    }];
}

// Used by `$ santactl fileinfo`.
- (nonnull SNTCachedDecision *)decisionForFilePath:(nonnull NSString *)filePath
                                       identifiers:(nonnull SNTRuleIdentifiers *)identifiers {
  MOLCodesignChecker *csInfo;
  NSError *error;

  SNTFileInfo *fileInfo = [[SNTFileInfo alloc] initWithPath:filePath error:&error];
  if (!fileInfo) {
    LOGW(@"Failed to read file %@: %@", filePath, error.localizedDescription);
  } else {
    csInfo = [fileInfo codesignCheckerWithError:&error];
    if (error) {
      LOGW(@"Failed to get codesign ingo for file %@: %@", filePath, error.localizedDescription);
    }
  }

  return [self decisionForFileInfo:fileInfo
                            cdhash:identifiers.cdhash
                        fileSHA256:identifiers.binarySHA256
                 certificateSHA256:identifiers.certificateSHA256
                            teamID:identifiers.teamID
                         signingID:identifiers.signingID
              isProdSignedCallback:^BOOL {
                if (csInfo) {
                  // Development OID values defined by Apple and used by the Security Framework
                  // https://images.apple.com/certificateauthority/pdf/Apple_WWDR_CPS_v1.31.pdf
                  NSArray *keys = @[ @"1.2.840.113635.100.6.1.2", @"1.2.840.113635.100.6.1.12" ];
                  NSDictionary *vals = CFBridgingRelease(SecCertificateCopyValues(
                    csInfo.leafCertificate.certRef, (__bridge CFArrayRef)keys, NULL));
                  return vals.count == 0;
                } else {
                  return NO;
                }
              }
        entitlementsFilterCallback:nil];
}

///
///  Checks whether the file at @c path is in-scope for checking with Santa.
///
///  Files that are out of scope:
///    + Non Mach-O files that are not part of an installer package.
///    + Files in allowed path.
///
///  @return @c YES if file is in scope, @c NO otherwise.
///
- (NSString *)fileIsScopeAllowed:(SNTFileInfo *)fi {
  if (!fi) return nil;

  // Determine if file is within an allowed path
  NSRegularExpression *re = [[SNTConfigurator configurator] allowedPathRegex];
  if ([re numberOfMatchesInString:fi.path options:0 range:NSMakeRange(0, fi.path.length)]) {
    return @"Allowed Path Regex";
  }

  // If file is not a Mach-O file, we're not interested.
  if (!fi.isMachO) {
    return @"Not a Mach-O";
  }

  return nil;
}

- (NSString *)fileIsScopeBlocked:(SNTFileInfo *)fi {
  if (!fi) return nil;

  NSRegularExpression *re = [[SNTConfigurator configurator] blockedPathRegex];
  if ([re numberOfMatchesInString:fi.path options:0 range:NSMakeRange(0, fi.path.length)]) {
    return @"Blocked Path Regex";
  }

  if ([[SNTConfigurator configurator] enablePageZeroProtection] && fi.isMissingPageZero) {
    return @"Missing __PAGEZERO";
  }

  return nil;
}

@end

1	/// Copyright 2015 Google Inc. All rights reserved.
2	///
3	/// Licensed under the Apache License, Version 2.0 (the "License");
4	/// you may not use this file except in compliance with the License.
5	/// You may obtain a copy of the License at
6	///
7	/// http://www.apache.org/licenses/LICENSE-2.0
8	///
9	/// Unless required by applicable law or agreed to in writing, software
10	/// distributed under the License is distributed on an "AS IS" BASIS,
11	/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12	/// See the License for the specific language governing permissions and
13	/// limitations under the License.
14
15	#import "Source/santad/SNTPolicyProcessor.h"
16	#include <Foundation/Foundation.h>
17
18	#include <Kernel/kern/cs_blobs.h>
19	#import <MOLCodesignChecker/MOLCodesignChecker.h>
20	#import <Security/SecCode.h>
21	#import <Security/Security.h>
22
23	#import "Source/common/SNTCachedDecision.h"
24	#import "Source/common/SNTConfigurator.h"
25	#import "Source/common/SNTDeepCopy.h"
26	#import "Source/common/SNTFileInfo.h"
27	#import "Source/common/SNTLogging.h"
28	#import "Source/common/SNTRule.h"
29	#import "Source/santad/DataLayer/SNTRuleTable.h"
30	#include "absl/container/flat_hash_map.h"
31
32	@interface SNTPolicyProcessor ()
33	@property SNTRuleTable *ruleTable;
34	@property SNTConfigurator *configurator;
35	@end
36
37	@implementation SNTPolicyProcessor
38
39	- (instancetype)initWithRuleTable:(SNTRuleTable *)ruleTable {	53✔
40	self = [super init];	53✔
41	if (self) {	53!
42	_ruleTable = ruleTable;	53✔
43	_configurator = [SNTConfigurator configurator];	53✔
44	}	53✔
45	return self;	53✔
46	}	53✔
47
48	// This method applies the rules to the cached decision object.
49	//
50	// It returns YES if the decision was made, NO if the decision was not made.
51	- (BOOL)decision:(SNTCachedDecision *)cd
52	forRule:(SNTRule *)rule
53	withTransitiveRules:(BOOL)enableTransitiveRules {	83✔
54	static const auto decisions =	83✔
55	absl::flat_hash_map<std::pair<SNTRuleType, SNTRuleState>, SNTEventState>{	83✔
56	{{SNTRuleTypeCDHash, SNTRuleStateAllow}, SNTEventStateAllowCDHash},	83✔
57	{{SNTRuleTypeCDHash, SNTRuleStateAllowCompiler}, SNTEventStateAllowCompiler},	83✔
58	{{SNTRuleTypeCDHash, SNTRuleStateBlock}, SNTEventStateBlockCDHash},	83✔
59	{{SNTRuleTypeCDHash, SNTRuleStateSilentBlock}, SNTEventStateBlockCDHash},	83✔
60	{{SNTRuleTypeBinary, SNTRuleStateAllow}, SNTEventStateAllowBinary},	83✔
61	{{SNTRuleTypeBinary, SNTRuleStateAllowTransitive}, SNTEventStateAllowTransitive},	83✔
62	{{SNTRuleTypeBinary, SNTRuleStateAllowCompiler}, SNTEventStateAllowCompiler},	83✔
63	{{SNTRuleTypeBinary, SNTRuleStateSilentBlock}, SNTEventStateBlockBinary},	83✔
64	{{SNTRuleTypeBinary, SNTRuleStateBlock}, SNTEventStateBlockBinary},	83✔
65	{{SNTRuleTypeSigningID, SNTRuleStateAllow}, SNTEventStateAllowSigningID},	83✔
66	{{SNTRuleTypeSigningID, SNTRuleStateAllowCompiler}, SNTEventStateAllowCompiler},	83✔
67	{{SNTRuleTypeSigningID, SNTRuleStateSilentBlock}, SNTEventStateBlockSigningID},	83✔
68	{{SNTRuleTypeSigningID, SNTRuleStateBlock}, SNTEventStateBlockSigningID},	83✔
69	{{SNTRuleTypeCertificate, SNTRuleStateAllow}, SNTEventStateAllowCertificate},	83✔
70	{{SNTRuleTypeCertificate, SNTRuleStateSilentBlock}, SNTEventStateBlockCertificate},	83✔
71	{{SNTRuleTypeCertificate, SNTRuleStateBlock}, SNTEventStateBlockCertificate},	83✔
72	{{SNTRuleTypeTeamID, SNTRuleStateAllow}, SNTEventStateAllowTeamID},	83✔
73	{{SNTRuleTypeTeamID, SNTRuleStateSilentBlock}, SNTEventStateBlockTeamID},	83✔
74	{{SNTRuleTypeTeamID, SNTRuleStateBlock}, SNTEventStateBlockTeamID},	83✔
75	};	83✔
76
77	auto iterator = decisions.find(std::pair<SNTRuleType, SNTRuleState>{rule.type, rule.state});	83✔
78	if (iterator != decisions.end()) {	83✔
79	cd.decision = iterator->second;	80✔
80	} else {	80✔
81	// If we have an invalid state combination then either we have stale data in
82	// the database or a programming error. We treat this as if the
83	// corresponding rule was not found.
84	LOGE(@"Invalid rule type/state combination %ld/%ld", rule.type, rule.state);	3✔
85	return NO;	3✔
86	}	3✔
87
88	switch (rule.state) {	80✔
89	case SNTRuleStateSilentBlock: cd.silentBlock = YES; break;	10✔
90	case SNTRuleStateAllowCompiler:	11✔
91	if (!enableTransitiveRules) {	11✔
92	switch (rule.type) {	5✔
93	case SNTRuleTypeCDHash: cd.decision = SNTEventStateAllowCDHash; break;	2✔
94	case SNTRuleTypeBinary: cd.decision = SNTEventStateAllowBinary; break;	2✔
95	case SNTRuleTypeSigningID: cd.decision = SNTEventStateAllowSigningID; break;	1✔
NEW 96	default:	×
97	// Programming error. Something's marked as a compiler that shouldn't
98	// be.
NEW 99	LOGE(@"Invalid compiler rule type %ld", rule.type);	×
NEW 100	[NSException	×
NEW 101	raise:@"Invalid compiler rule type"	×
NEW 102	format:@"decision:forRule:withTransitiveRules: Unexpected compiler rule type: %ld",	×
NEW 103	rule.type];	×
NEW 104	break;	×
105	}	5✔
106	}	5✔
107	break;	11✔
108	case SNTRuleStateAllowTransitive:	11✔
109	// If transitive rules are disabled, then we treat
110	// SNTRuleStateAllowTransitive rules as if a matching rule was not found
111	// and set the state to unknown. Otherwise the decision map will have already set
112	// the EventState to SNTEventStateAllowTransitive.
113	if (!enableTransitiveRules) {	4✔
114	cd.decision = SNTEventStateUnknown;	2✔
115	return NO;	2✔
116	}	2✔
117	break;	2✔
118	default:	55✔
119	// If its not one of the special cases above, we don't need to do anything.
120	break;	55✔
121	}	80✔
122
123	// We know we have a match so apply the custom messages
124	cd.customMsg = rule.customMsg;	78✔
125	cd.customURL = rule.customURL;	78✔
126
127	return YES;	78✔
128	}	80✔
129
130	static void UpdateCachedDecisionSigningInfo(
131	SNTCachedDecision cd, MOLCodesignChecker csInfo,
132	NSDictionary _Nullable (^entitlementsFilterCallback)(NSDictionary _Nullable entitlements)) {	44✔
133	cd.certSHA256 = csInfo.leafCertificate.SHA256;	44✔
134	cd.certCommonName = csInfo.leafCertificate.commonName;	44✔
135	cd.certChain = csInfo.certificates;	44✔
136	// Check if we need to get teamID from code signing.
137	if (!cd.teamID) {	44✔
138	cd.teamID = csInfo.teamID;	31✔
139	}	31✔
140
141	// Ensure that if no teamID exists that the signing info confirms it is a
142	// platform binary. If not, remove the signingID.
143	if (!cd.teamID && cd.signingID) {	44!
NEW 144	if (!csInfo.platformBinary) {	×
NEW 145	cd.signingID = nil;	×
NEW 146	}	×
NEW 147	}	×
148
149	NSDictionary *entitlements = csInfo.entitlements;	44✔
150
151	if (entitlementsFilterCallback) {	44!
152	cd.entitlements = entitlementsFilterCallback(entitlements);	44✔
153	cd.entitlementsFiltered = (cd.entitlements.count != entitlements.count);	44✔
154	} else {	44✔
NEW 155	cd.entitlements = [entitlements sntDeepCopy];	×
NEW 156	cd.entitlementsFiltered = NO;	×
NEW 157	}	×
158	}	44✔
159
160	- (nonnull SNTCachedDecision )decisionForFileInfo:(nonnull SNTFileInfo )fileInfo
161	cdhash:(nullable NSString *)cdhash
162	fileSHA256:(nullable NSString *)fileSHA256
163	certificateSHA256:(nullable NSString *)certificateSHA256
164	teamID:(nullable NSString *)teamID
165	signingID:(nullable NSString *)signingID
166	isProdSignedCallback:(BOOL (^_Nonnull)())isProdSignedCallback
167	entitlementsFilterCallback:
168	(NSDictionary *_Nullable (^_Nullable)(
169	NSDictionary *_Nullable entitlements))entitlementsFilterCallback {	51✔
170	// Check the hash before allocating a SNTCachedDecision.
171	NSString *fileHash = fileSHA256 ?: fileInfo.SHA256;	51!
172	SNTClientMode mode = [self.configurator clientMode];	51✔
173
174	// If the binary is a critical system binary, don't check its signature.
175	// The binary was validated at startup when the rule table was initialized.
176	SNTCachedDecision *systemCd = self.ruleTable.criticalSystemBinaries[fileHash];	51✔
177	if (systemCd) {	51✔
178	systemCd.decisionClientMode = mode;	1✔
179	return systemCd;	1✔
180	}	1✔
181
182	// Allocate a new cached decision for the execution.
183	SNTCachedDecision *cd = [[SNTCachedDecision alloc] init];	50✔
184	cd.cdhash = cdhash;	50✔
185	cd.sha256 = fileHash;	50✔
186	cd.teamID = teamID;	50✔
187	cd.signingID = signingID;	50✔
188	cd.decisionClientMode = mode;	50✔
189	cd.quarantineURL = fileInfo.quarantineDataURL;	50✔
190
191	NSError *csInfoError;	50✔
192	if (certificateSHA256.length) {	50!
193	cd.certSHA256 = certificateSHA256;	×
194	} else {	50✔
195	// Grab the code signature, if there's an error don't try to capture
196	// any of the signature details. Also clear out any rule lookup parameters
197	// that would require being validly signed.
198	MOLCodesignChecker *csInfo = [fileInfo codesignCheckerWithError:&csInfoError];	50✔
199	if (csInfoError) {	50✔
200	csInfo = nil;	6✔
201	cd.decisionExtra =	6✔
202	[NSString stringWithFormat:@"Signature ignored due to error: %ld", (long)csInfoError.code];	6✔
203	cd.teamID = nil;	6✔
204	cd.signingID = nil;	6✔
205	cd.cdhash = nil;	6✔
206	} else {	44✔
207	UpdateCachedDecisionSigningInfo(cd, csInfo, entitlementsFilterCallback);	44✔
208	}	44✔
209	}	50✔
210
211	// Do not evaluate TeamID/SigningID rules for dev-signed code based on the
212	// assumption that orgs are generally more relaxed about dev signed cert
213	// protections and users can more easily produce dev-signed code that
214	// would otherwise be inadvertently allowed.
215	// Note: Only perform the check if the SigningID is still set, otherwise
216	// it is unsigned or had issues above that already cleared the values.
217	if (cd.signingID && !isProdSignedCallback()) {	50!
218	LOGD(@"Ignoring TeamID and SigningID rules for code not signed with production cert: %@",	×
219	cd.signingID);	×
220	cd.teamID = nil;	×
221	cd.signingID = nil;	×
222	}	×
223
224	SNTRule *rule =	50✔
225	[self.ruleTable ruleForIdentifiers:(struct RuleIdentifiers){.cdhash = cd.cdhash,	50✔
226	.binarySHA256 = cd.sha256,	50✔
227	.signingID = cd.signingID,	50✔
228	.certificateSHA256 = cd.certSHA256,	50✔
229	.teamID = cd.teamID}];	50✔
230	if (rule) {	50✔
231	// If we have a rule match we don't need to process any further.
232	if ([self decision:cd	42✔
233	forRule:rule	42✔
234	withTransitiveRules:self.configurator.enableTransitiveRules]) {	42✔
235	return cd;	40✔
236	}	40✔
237	}	42✔
238
239	if ([[SNTConfigurator configurator] enableBadSignatureProtection] && csInfoError &&	10!
240	csInfoError.code != errSecCSUnsigned) {	10!
241	cd.decisionExtra =	×
242	[NSString stringWithFormat:@"Blocked due to signature error: %ld", (long)csInfoError.code];	×
243	cd.decision = SNTEventStateBlockCertificate;	×
244	return cd;	×
245	}	×
246
247	NSString *msg = [self fileIsScopeBlocked:fileInfo];	10✔
248	if (msg) {	10!
249	cd.decisionExtra = msg;	×
250	cd.decision = SNTEventStateBlockScope;	×
251	return cd;	×
252	}	×
253
254	msg = [self fileIsScopeAllowed:fileInfo];	10✔
255	if (msg) {	10✔
256	cd.decisionExtra = msg;	2✔
257	cd.decision = SNTEventStateAllowScope;	2✔
258	return cd;	2✔
259	}	2✔
260
261	switch (mode) {	8✔
262	case SNTClientModeMonitor: cd.decision = SNTEventStateAllowUnknown; return cd;	3✔
263	case SNTClientModeLockdown: cd.decision = SNTEventStateBlockUnknown; return cd;	4✔
264	default: cd.decision = SNTEventStateBlockUnknown; return cd;	1✔
265	}	8✔
266	}	8✔
267
268	- (nonnull SNTCachedDecision )decisionForFileInfo:(nonnull SNTFileInfo )fileInfo
269	targetProcess:(nonnull const es_process_t *)targetProc
270	entitlementsFilterCallback:
271	(NSDictionary *_Nullable (^_Nonnull)(
272	const char *_Nullable teamID,
273	NSDictionary *_Nullable entitlements))entitlementsFilterCallback {	51✔
274	NSString *signingID;	51✔
275	NSString *teamID;	51✔
276	NSString *cdhash;	51✔
277
278	const char *entitlementsFilterTeamID = NULL;	51✔
279
280	if (targetProc->codesigning_flags & CS_SIGNED && targetProc->codesigning_flags & CS_VALID) {	51!
281	if (targetProc->signing_id.length > 0) {	51✔
282	if (targetProc->team_id.length > 0) {	13!
283	entitlementsFilterTeamID = targetProc->team_id.data;	13✔
284	teamID = [NSString stringWithUTF8String:targetProc->team_id.data];	13✔
285	signingID =	13✔
286	[NSString stringWithFormat:@"%@:%@", teamID,	13✔
287	[NSString stringWithUTF8String:targetProc->signing_id.data]];	13✔
288	} else if (targetProc->is_platform_binary) {	13!
289	entitlementsFilterTeamID = "platform";	×
290	signingID =	×
291	[NSString stringWithFormat:@"platform:%@",	×
292	[NSString stringWithUTF8String:targetProc->signing_id.data]];	×
293	}	×
294	}	13✔
295
296	// Only consider the CDHash for processes that have CS_KILL or CS_HARD set.
297	// This ensures that the OS will kill the process if the CDHash was tampered
298	// with and code was loaded that didn't match a page hash.
299	if (targetProc->codesigning_flags & CS_KILL \|\| targetProc->codesigning_flags & CS_HARD) {	51!
300	static NSString *const kCDHashFormatString = @"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x"	28✔
301	"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x";	28✔
302
303	const uint8_t *buf = targetProc->cdhash;	28✔
304	cdhash = [[NSString alloc] initWithFormat:kCDHashFormatString, buf[0], buf[1], buf[2], buf[3],	28✔
305	buf[4], buf[5], buf[6], buf[7], buf[8], buf[9],	28✔
306	buf[10], buf[11], buf[12], buf[13], buf[14],	28✔
307	buf[15], buf[16], buf[17], buf[18], buf[19]];	28✔
308	}	28✔
309	}	51✔
310
311	return [self decisionForFileInfo:fileInfo	51✔
312	cdhash:cdhash	51✔
313	fileSHA256:nil	51✔
314	certificateSHA256:nil	51✔
315	teamID:teamID	51✔
316	signingID:signingID	51✔
317	isProdSignedCallback:^BOOL {	51✔
318	return ((targetProc->codesigning_flags & CS_DEV_CODE) == 0);	13✔
319	}	13✔
320	entitlementsFilterCallback:^NSDictionary (NSDictionary entitlements) {	51✔
321	return entitlementsFilterCallback(entitlementsFilterTeamID, entitlements);	44✔
322	}];	44✔
323	}	51✔
324
325	// Used by `$ santactl fileinfo`.
326	- (nonnull SNTCachedDecision )decisionForFilePath:(nonnull NSString )filePath
327	identifiers:(nonnull SNTRuleIdentifiers *)identifiers {	×
328	MOLCodesignChecker *csInfo;	×
329	NSError *error;	×
330
331	SNTFileInfo *fileInfo = [[SNTFileInfo alloc] initWithPath:filePath error:&error];	×
332	if (!fileInfo) {	×
333	LOGW(@"Failed to read file %@: %@", filePath, error.localizedDescription);	×
334	} else {	×
335	csInfo = [fileInfo codesignCheckerWithError:&error];	×
336	if (error) {	×
337	LOGW(@"Failed to get codesign ingo for file %@: %@", filePath, error.localizedDescription);	×
338	}	×
339	}	×
340
341	return [self decisionForFileInfo:fileInfo	×
342	cdhash:identifiers.cdhash	×
343	fileSHA256:identifiers.binarySHA256	×
344	certificateSHA256:identifiers.certificateSHA256	×
345	teamID:identifiers.teamID	×
346	signingID:identifiers.signingID	×
347	isProdSignedCallback:^BOOL {	×
348	if (csInfo) {	×
349	// Development OID values defined by Apple and used by the Security Framework
350	// https://images.apple.com/certificateauthority/pdf/Apple_WWDR_CPS_v1.31.pdf
351	NSArray *keys = @[ @"1.2.840.113635.100.6.1.2", @"1.2.840.113635.100.6.1.12" ];	×
352	NSDictionary *vals = CFBridgingRelease(SecCertificateCopyValues(	×
353	csInfo.leafCertificate.certRef, (__bridge CFArrayRef)keys, NULL));	×
354	return vals.count == 0;	×
355	} else {	×
356	return NO;	×
357	}	×
358	}	×
359	entitlementsFilterCallback:nil];	×
360	}	×
361
362	///
363	/// Checks whether the file at @c path is in-scope for checking with Santa.
364	///
365	/// Files that are out of scope:
366	/// + Non Mach-O files that are not part of an installer package.
367	/// + Files in allowed path.
368	///
369	/// @return @c YES if file is in scope, @c NO otherwise.
370	///
371	- (NSString )fileIsScopeAllowed:(SNTFileInfo )fi {	10✔
372	if (!fi) return nil;	10!
373
374	// Determine if file is within an allowed path
375	NSRegularExpression *re = [[SNTConfigurator configurator] allowedPathRegex];	10✔
376	if ([re numberOfMatchesInString:fi.path options:0 range:NSMakeRange(0, fi.path.length)]) {	10!
377	return @"Allowed Path Regex";	×
378	}	×
379
380	// If file is not a Mach-O file, we're not interested.
381	if (!fi.isMachO) {	10✔
382	return @"Not a Mach-O";	2✔
383	}	2✔
384
385	return nil;	8✔
386	}	10✔
387
388	- (NSString )fileIsScopeBlocked:(SNTFileInfo )fi {	10✔
389	if (!fi) return nil;	10!
390
391	NSRegularExpression *re = [[SNTConfigurator configurator] blockedPathRegex];	10✔
392	if ([re numberOfMatchesInString:fi.path options:0 range:NSMakeRange(0, fi.path.length)]) {	10!
393	return @"Blocked Path Regex";	×
394	}	×
395
396	if ([[SNTConfigurator configurator] enablePageZeroProtection] && fi.isMissingPageZero) {	10!
397	return @"Missing __PAGEZERO";	×
398	}	×
399
400	return nil;	10✔
401	}	10✔
402
403	@end

google / santa / 9021469716

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