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