caps/ExpandedPrincipal.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=2 sw=2 et tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "ExpandedPrincipal.h"
   8 #include "nsIClassInfoImpl.h"
   9 #include "nsIObjectInputStream.h"
  10 #include "nsReadableUtils.h"
  11 #include "mozilla/Base64.h"
  12 #include "json/json.h"
  13
  14 using namespace mozilla;
  15
  16 NS_IMPL_CLASSINFO(ExpandedPrincipal, nullptr, nsIClassInfo::MAIN_THREAD_ONLY,
  17                   NS_EXPANDEDPRINCIPAL_CID)
  18 NS_IMPL_QUERY_INTERFACE_CI(ExpandedPrincipal, nsIPrincipal,
  19                            nsIExpandedPrincipal)
  20 NS_IMPL_CI_INTERFACE_GETTER(ExpandedPrincipal, nsIPrincipal,
  21                             nsIExpandedPrincipal)
  22
  23 struct OriginComparator {
  24   bool LessThan(nsIPrincipal* a, nsIPrincipal* b) const {
  25     nsAutoCString originA;
  26     DebugOnly<nsresult> rv = a->GetOrigin(originA);
  27     MOZ_ASSERT(NS_SUCCEEDED(rv));
  28     nsAutoCString originB;
  29     rv = b->GetOrigin(originB);
  30     MOZ_ASSERT(NS_SUCCEEDED(rv));
  31     return originA < originB;
  32   }
  33
  34   bool Equals(nsIPrincipal* a, nsIPrincipal* b) const {
  35     nsAutoCString originA;
  36     DebugOnly<nsresult> rv = a->GetOrigin(originA);
  37     MOZ_ASSERT(NS_SUCCEEDED(rv));
  38     nsAutoCString originB;
  39     rv = b->GetOrigin(originB);
  40     MOZ_ASSERT(NS_SUCCEEDED(rv));
  41     return a == b;
  42   }
  43 };
  44
  45 ExpandedPrincipal::ExpandedPrincipal(
  46     nsTArray<nsCOMPtr<nsIPrincipal>>&& aPrincipals,
  47     const nsACString& aOriginNoSuffix, const OriginAttributes& aAttrs)
  48     : BasePrincipal(eExpandedPrincipal, aOriginNoSuffix, aAttrs),
  49       mPrincipals(std::move(aPrincipals)) {}
  50
  51 ExpandedPrincipal::~ExpandedPrincipal() = default;
  52
  53 already_AddRefed<ExpandedPrincipal> ExpandedPrincipal::Create(
  54     const nsTArray<nsCOMPtr<nsIPrincipal>>& aAllowList,
  55     const OriginAttributes& aAttrs) {
  56   // We force the principals to be sorted by origin so that ExpandedPrincipal
  57   // origins can have a canonical form.
  58   nsTArray<nsCOMPtr<nsIPrincipal>> principals;
  59   OriginComparator c;
  60   for (size_t i = 0; i < aAllowList.Length(); ++i) {
  61     principals.InsertElementSorted(aAllowList[i], c);
  62   }
  63
  64   nsAutoCString origin;
  65   origin.AssignLiteral("[Expanded Principal [");
  66   StringJoinAppend(
  67       origin, ", "_ns, principals,
  68       [](nsACString& dest, const nsCOMPtr<nsIPrincipal>& principal) {
  69         nsAutoCString subOrigin;
  70         DebugOnly<nsresult> rv = principal->GetOrigin(subOrigin);
  71         MOZ_ASSERT(NS_SUCCEEDED(rv));
  72         dest.Append(subOrigin);
  73       });
  74   origin.AppendLiteral("]]");
  75
  76   RefPtr<ExpandedPrincipal> ep =
  77       new ExpandedPrincipal(std::move(principals), origin, aAttrs);
  78   return ep.forget();
  79 }
  80
  81 NS_IMETHODIMP
  82 ExpandedPrincipal::GetDomain(nsIURI** aDomain) {
  83   *aDomain = nullptr;
  84   return NS_OK;
  85 }
  86
  87 NS_IMETHODIMP
  88 ExpandedPrincipal::SetDomain(nsIURI* aDomain) { return NS_OK; }
  89
  90 bool ExpandedPrincipal::SubsumesInternal(
  91     nsIPrincipal* aOther,
  92     BasePrincipal::DocumentDomainConsideration aConsideration) {
  93   // If aOther is an ExpandedPrincipal too, we break it down into its component
  94   // nsIPrincipals, and check subsumes on each one.
  95   if (Cast(aOther)->Is<ExpandedPrincipal>()) {
  96     auto* expanded = Cast(aOther)->As<ExpandedPrincipal>();
  97
  98     for (auto& other : expanded->AllowList()) {
  99       // Use SubsumesInternal rather than Subsumes here, since OriginAttribute
 100       // checks are only done between non-expanded sub-principals, and we don't
 101       // need to incur the extra virtual call overhead.
 102       if (!SubsumesInternal(other, aConsideration)) {
 103         return false;
 104       }
 105     }
 106     return true;
 107   }
 108
 109   // We're dealing with a regular principal. One of our principals must subsume
 110   // it.
 111   for (uint32_t i = 0; i < mPrincipals.Length(); ++i) {
 112     if (Cast(mPrincipals[i])->Subsumes(aOther, aConsideration)) {
 113       return true;
 114     }
 115   }
 116
 117   return false;
 118 }
 119
 120 bool ExpandedPrincipal::MayLoadInternal(nsIURI* uri) {
 121   for (uint32_t i = 0; i < mPrincipals.Length(); ++i) {
 122     if (BasePrincipal::Cast(mPrincipals[i])->MayLoadInternal(uri)) {
 123       return true;
 124     }
 125   }
 126
 127   return false;
 128 }
 129
 130 uint32_t ExpandedPrincipal::GetHashValue() {
 131   MOZ_CRASH("extended principal should never be used as key in a hash map");
 132 }
 133
 134 NS_IMETHODIMP
 135 ExpandedPrincipal::GetURI(nsIURI** aURI) {
 136   *aURI = nullptr;
 137   return NS_OK;
 138 }
 139
 140 const nsTArray<nsCOMPtr<nsIPrincipal>>& ExpandedPrincipal::AllowList() {
 141   return mPrincipals;
 142 }
 143
 144 NS_IMETHODIMP
 145 ExpandedPrincipal::GetBaseDomain(nsACString& aBaseDomain) {
 146   return NS_ERROR_NOT_AVAILABLE;
 147 }
 148
 149 NS_IMETHODIMP
 150 ExpandedPrincipal::GetAddonId(nsAString& aAddonId) {
 151   aAddonId.Truncate();
 152   return NS_OK;
 153 };
 154
 155 bool ExpandedPrincipal::AddonHasPermission(const nsAtom* aPerm) {
 156   for (size_t i = 0; i < mPrincipals.Length(); ++i) {
 157     if (BasePrincipal::Cast(mPrincipals[i])->AddonHasPermission(aPerm)) {
 158       return true;
 159     }
 160   }
 161   return false;
 162 }
 163
 164 bool ExpandedPrincipal::AddonAllowsLoad(nsIURI* aURI,
 165                                         bool aExplicit /* = false */) {
 166   for (const auto& principal : mPrincipals) {
 167     if (Cast(principal)->AddonAllowsLoad(aURI, aExplicit)) {
 168       return true;
 169     }
 170   }
 171   return false;
 172 }
 173
 174 void ExpandedPrincipal::SetCsp(nsIContentSecurityPolicy* aCSP) { mCSP = aCSP; }
 175
 176 NS_IMETHODIMP
 177 ExpandedPrincipal::GetCsp(nsIContentSecurityPolicy** aCsp) {
 178   NS_IF_ADDREF(*aCsp = mCSP);
 179   return NS_OK;
 180 }
 181
 182 nsIPrincipal* ExpandedPrincipal::PrincipalToInherit(nsIURI* aRequestedURI) {
 183   if (aRequestedURI) {
 184     // If a given sub-principal subsumes the given URI, use that principal for
 185     // inheritance. In general, this only happens with certain CORS modes, loads
 186     // with forced principal inheritance, and creation of XML documents from
 187     // XMLHttpRequests or fetch requests. For URIs that normally inherit a
 188     // principal (such as data: URIs), we fall back to the last principal in the
 189     // allowlist.
 190     for (const auto& principal : mPrincipals) {
 191       if (Cast(principal)->MayLoadInternal(aRequestedURI)) {
 192         return principal;
 193       }
 194     }
 195   }
 196   return mPrincipals.LastElement();
 197 }
 198
 199 nsresult ExpandedPrincipal::GetScriptLocation(nsACString& aStr) {
 200   aStr.AssignLiteral("[Expanded Principal [");
 201   for (size_t i = 0; i < mPrincipals.Length(); ++i) {
 202     if (i != 0) {
 203       aStr.AppendLiteral(", ");
 204     }
 205
 206     nsAutoCString spec;
 207     nsresult rv =
 208         nsJSPrincipals::get(mPrincipals.ElementAt(i))->GetScriptLocation(spec);
 209     NS_ENSURE_SUCCESS(rv, rv);
 210
 211     aStr.Append(spec);
 212   }
 213   aStr.AppendLiteral("]]");
 214   return NS_OK;
 215 }
 216
 217 //////////////////////////////////////////
 218 // Methods implementing nsISerializable //
 219 //////////////////////////////////////////
 220
 221 // We've had way too many issues with unversioned serializations, so
 222 // explicitly version this one.
 223 static const uint32_t kSerializationVersion = 1;
 224
 225 NS_IMETHODIMP
 226 ExpandedPrincipal::Deserializer::Read(nsIObjectInputStream* aStream) {
 227   uint32_t version;
 228   nsresult rv = aStream->Read32(&version);
 229   if (version != kSerializationVersion) {
 230     MOZ_ASSERT(false,
 231                "We really need to add handling of the old(?) version here");
 232     return NS_ERROR_UNEXPECTED;
 233   }
 234
 235   uint32_t count;
 236   rv = aStream->Read32(&count);
 237   if (NS_FAILED(rv)) {
 238     return rv;
 239   }
 240
 241   nsTArray<nsCOMPtr<nsIPrincipal>> principals;
 242   if (!principals.SetCapacity(count, fallible)) {
 243     return NS_ERROR_OUT_OF_MEMORY;
 244   }
 245
 246   OriginComparator c;
 247   for (uint32_t i = 0; i < count; ++i) {
 248     nsCOMPtr<nsISupports> read;
 249     rv = aStream->ReadObject(true, getter_AddRefs(read));
 250     if (NS_FAILED(rv)) {
 251       return rv;
 252     }
 253
 254     nsCOMPtr<nsIPrincipal> principal = do_QueryInterface(read);
 255     if (!principal) {
 256       return NS_ERROR_UNEXPECTED;
 257     }
 258
 259     // Play it safe and InsertElementSorted, in case the sort order
 260     // changed for some bizarre reason.
 261     principals.InsertElementSorted(std::move(principal), c);
 262   }
 263
 264   mPrincipal = ExpandedPrincipal::Create(principals, OriginAttributes());
 265   return NS_OK;
 266 }
 267
 268 nsresult ExpandedPrincipal::GetSiteIdentifier(SiteIdentifier& aSite) {
 269   // Call GetSiteIdentifier on each of our principals and return a new
 270   // ExpandedPrincipal.
 271
 272   nsTArray<nsCOMPtr<nsIPrincipal>> allowlist;
 273   for (const auto& principal : mPrincipals) {
 274     SiteIdentifier site;
 275     nsresult rv = Cast(principal)->GetSiteIdentifier(site);
 276     NS_ENSURE_SUCCESS(rv, rv);
 277     allowlist.AppendElement(site.GetPrincipal());
 278   }
 279
 280   RefPtr<ExpandedPrincipal> expandedPrincipal =
 281       ExpandedPrincipal::Create(allowlist, OriginAttributesRef());
 282   MOZ_ASSERT(expandedPrincipal, "ExpandedPrincipal::Create returned nullptr?");
 283
 284   aSite.Init(expandedPrincipal);
 285   return NS_OK;
 286 }
 287
 288 nsresult ExpandedPrincipal::PopulateJSONObject(Json::Value& aObject) {
 289   nsAutoCString principalList;
 290   // First item through we have a blank separator and append the next result
 291   nsAutoCString sep;
 292   for (auto& principal : mPrincipals) {
 293     nsAutoCString JSON;
 294     BasePrincipal::Cast(principal)->ToJSON(JSON);
 295     // This is blank for the first run through so the last in the list doesn't
 296     // add a separator
 297     principalList.Append(sep);
 298     sep = ',';
 299     // Values currently only copes with strings so encode into base64 to allow a
 300     // CSV safely.
 301     nsresult rv;
 302     rv = Base64EncodeAppend(JSON, principalList);
 303     NS_ENSURE_SUCCESS(rv, rv);
 304   }
 305   aObject[std::to_string(eSpecs)] = principalList.get();
 306
 307   nsAutoCString suffix;
 308   OriginAttributesRef().CreateSuffix(suffix);
 309   if (suffix.Length() > 0) {
 310     aObject[std::to_string(eSuffix)] = suffix.get();
 311   }
 312
 313   return NS_OK;
 314 }
 315
 316 already_AddRefed<BasePrincipal> ExpandedPrincipal::FromProperties(
 317     nsTArray<ExpandedPrincipal::KeyVal>& aFields) {
 318   MOZ_ASSERT(aFields.Length() == eMax + 1, "Must have all the keys");
 319   nsTArray<nsCOMPtr<nsIPrincipal>> allowList;
 320   OriginAttributes attrs;
 321   // The odd structure here is to make the code to not compile
 322   // if all the switch enum cases haven't been codified
 323   for (const auto& field : aFields) {
 324     switch (field.key) {
 325       case ExpandedPrincipal::eSpecs:
 326         if (!field.valueWasSerialized) {
 327           MOZ_ASSERT(false,
 328                      "Expanded principals require specs in serialized JSON");
 329           return nullptr;
 330         }
 331         for (const nsACString& each : field.value.Split(',')) {
 332           nsAutoCString result;
 333           nsresult rv;
 334           rv = Base64Decode(each, result);
 335           MOZ_ASSERT(NS_SUCCEEDED(rv), "failed to decode");
 336
 337           NS_ENSURE_SUCCESS(rv, nullptr);
 338           nsCOMPtr<nsIPrincipal> principal = BasePrincipal::FromJSON(result);
 339           allowList.AppendElement(principal);
 340         }
 341         break;
 342       case ExpandedPrincipal::eSuffix:
 343         if (field.valueWasSerialized) {
 344           bool ok = attrs.PopulateFromSuffix(field.value);
 345           if (!ok) {
 346             return nullptr;
 347           }
 348         }
 349         break;
 350     }
 351   }
 352
 353   if (allowList.Length() == 0) {
 354     return nullptr;
 355   }
 356
 357   RefPtr<ExpandedPrincipal> expandedPrincipal =
 358       ExpandedPrincipal::Create(allowList, attrs);
 359
 360   return expandedPrincipal.forget();
 361 }
 362
 363 NS_IMETHODIMP
 364 ExpandedPrincipal::IsThirdPartyURI(nsIURI* aURI, bool* aRes) {
 365   // ExpandedPrincipal for extension content scripts consist of two principals,
 366   // the document's principal and the extension's principal.
 367   // To make sure that the third-party check behaves like the web page on which
 368   // the content script is running, ignore the extension's principal.
 369
 370   for (const auto& principal : mPrincipals) {
 371     if (!Cast(principal)->AddonPolicy()) {
 372       return Cast(principal)->IsThirdPartyURI(aURI, aRes);
 373     }
 374   }
 375
 376   if (mPrincipals.IsEmpty()) {
 377     *aRes = true;
 378     return NS_OK;
 379   }
 380
 381   return Cast(mPrincipals[0])->IsThirdPartyURI(aURI, aRes);
 382 }