import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

security/sandbox/linux/SandboxBrokerClient.cpp

@@ -0,0 +1,247 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "SandboxBrokerClient.h"
+#include "SandboxInfo.h"
+#include "SandboxLogging.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/NullPtr.h"
+#include "base/strings/safe_sprintf.h"
+
+namespace mozilla {
+
+SandboxBrokerClient::SandboxBrokerClient(int aFd)
+: mFileDesc(aFd)
+{
+}
+
+SandboxBrokerClient::~SandboxBrokerClient()
+{
+  close(mFileDesc);
+}
+
+int
+SandboxBrokerClient::DoCall(const Request* aReq, const char* aPath,
+                            const char* aPath2, void* aResponseBuff,
+                            bool expectFd)
+{
+  // Remap /proc/self to the actual pid, so that the broker can open
+  // it.  This happens here instead of in the broker to follow the
+  // principle of least privilege and keep the broker as simple as
+  // possible.  (Note: when pid namespaces happen, this will also need
+  // to remap the inner pid to the outer pid.)
+  // We only remap the first path.
+  static const char kProcSelf[] = "/proc/self/";
+  static const size_t kProcSelfLen = sizeof(kProcSelf) - 1;
+  const char* path = aPath;
+  // This buffer just needs to be large enough for any such path that
+  // the policy would actually allow.  sizeof("/proc/2147483647/") == 18.
+  char rewrittenPath[64];
+  if (strncmp(aPath, kProcSelf, kProcSelfLen) == 0) {
+    ssize_t len =
+      base::strings::SafeSPrintf(rewrittenPath, "/proc/%d/%s",
+                                 getpid(), aPath + kProcSelfLen);
+    if (static_cast<size_t>(len) < sizeof(rewrittenPath)) {
+      if (SandboxInfo::Get().Test(SandboxInfo::kVerbose)) {
+        SANDBOX_LOG_ERROR("rewriting %s -> %s", aPath, rewrittenPath);
+      }
+      path = rewrittenPath;
+    } else {
+      SANDBOX_LOG_ERROR("not rewriting unexpectedly long path %s", aPath);
+    }
+  }
+
+  struct iovec ios[3];
+  int respFds[2];
+
+  // Set up iovecs for request + path.
+  ios[0].iov_base = const_cast<Request*>(aReq);
+  ios[0].iov_len = sizeof(*aReq);
+  ios[1].iov_base = const_cast<char*>(path);
+  ios[1].iov_len = strlen(path) + 1;
+  if (aPath2 != nullptr) {
+    ios[2].iov_base = const_cast<char*>(aPath2);
+    ios[2].iov_len = strlen(aPath2) + 1;
+  } else {
+    ios[2].iov_base = 0;
+    ios[2].iov_len = 0;
+  }
+  if (ios[1].iov_len > kMaxPathLen) {
+    return -ENAMETOOLONG;
+  }
+  if (ios[2].iov_len > kMaxPathLen) {
+    return -ENAMETOOLONG;
+  }
+
+  // Create response socket and send request.
+  if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, respFds) < 0) {
+    return -errno;
+  }
+  const ssize_t sent = SendWithFd(mFileDesc, ios, 3, respFds[1]);
+  const int sendErrno = errno;
+  MOZ_ASSERT(sent < 0 ||
+             static_cast<size_t>(sent) == ios[0].iov_len
+                                        + ios[1].iov_len
+                                        + ios[2].iov_len);
+  close(respFds[1]);
+  if (sent < 0) {
+    close(respFds[0]);
+    return -sendErrno;
+  }
+
+  // Set up iovecs for response.
+  Response resp;
+  ios[0].iov_base = &resp;
+  ios[0].iov_len = sizeof(resp);
+  if (aResponseBuff) {
+    ios[1].iov_base = aResponseBuff;
+    ios[1].iov_len = aReq->mBufSize;
+  } else {
+    ios[1].iov_base = nullptr;
+    ios[1].iov_len = 0;
+  }
+
+  // Wait for response and return appropriately.
+  int openedFd = -1;
+  const ssize_t recvd = RecvWithFd(respFds[0], ios, aResponseBuff ? 2 : 1,
+                                   expectFd ? &openedFd : nullptr);
+  const int recvErrno = errno;
+  close(respFds[0]);
+  if (recvd < 0) {
+    return -recvErrno;
+  }
+  if (recvd == 0) {
+    SANDBOX_LOG_ERROR("Unexpected EOF, op %d flags 0%o path %s",
+                      aReq->mOp, aReq->mFlags, path);
+    return -EIO;
+  }
+  MOZ_ASSERT(static_cast<size_t>(recvd) <= ios[0].iov_len + ios[1].iov_len);
+  // Some calls such as readlink return a size if successful
+  if (resp.mError >= 0) {
+    // Success!
+    if (expectFd) {
+      MOZ_ASSERT(openedFd >= 0);
+      return openedFd;
+    }
+    return resp.mError;
+  }
+  if (SandboxInfo::Get().Test(SandboxInfo::kVerbose)) {
+    // Keep in mind that "rejected" files can include ones that don't
+    // actually exist, if it's something that's optional or part of a
+    // search path (e.g., shared libraries).  In those cases, this
+    // error message is expected.
+    SANDBOX_LOG_ERROR("Rejected errno %d op %d flags 0%o path %s",
+                      resp.mError, aReq->mOp, aReq->mFlags, path);
+  }
+  if (openedFd >= 0) {
+    close(openedFd);
+  }
+  return resp.mError;
+}
+
+int
+SandboxBrokerClient::Open(const char* aPath, int aFlags)
+{
+  Request req = { SANDBOX_FILE_OPEN, aFlags, 0 };
+  int maybeFd = DoCall(&req, aPath, nullptr, nullptr, true);
+  if (maybeFd >= 0) {
+    // NSPR has opinions about file flags.  Fix O_CLOEXEC.
+    if ((aFlags & O_CLOEXEC) == 0) {
+      fcntl(maybeFd, F_SETFD, 0);
+    }
+  }
+  return maybeFd;
+}
+
+int
+SandboxBrokerClient::Access(const char* aPath, int aMode)
+{
+  Request req = { SANDBOX_FILE_ACCESS, aMode, 0 };
+  return DoCall(&req, aPath, nullptr, nullptr, false);
+}
+
+int
+SandboxBrokerClient::Stat(const char* aPath, statstruct* aStat)
+{
+  Request req = { SANDBOX_FILE_STAT, 0, sizeof(statstruct) };
+  return DoCall(&req, aPath, nullptr, (void*)aStat, false);
+}
+
+int
+SandboxBrokerClient::LStat(const char* aPath, statstruct* aStat)
+{
+  Request req = { SANDBOX_FILE_STAT, O_NOFOLLOW, sizeof(statstruct) };
+  return DoCall(&req, aPath, nullptr, (void*)aStat, false);
+}
+
+int
+SandboxBrokerClient::Chmod(const char* aPath, int aMode)
+{
+  Request req = {SANDBOX_FILE_CHMOD, aMode, 0};
+  return DoCall(&req, aPath, nullptr, nullptr, false);
+}
+
+int
+SandboxBrokerClient::Link(const char* aOldPath, const char* aNewPath)
+{
+  Request req = {SANDBOX_FILE_LINK, 0, 0};
+  return DoCall(&req, aOldPath, aNewPath, nullptr, false);
+}
+
+int
+SandboxBrokerClient::Symlink(const char* aOldPath, const char* aNewPath)
+{
+  Request req = {SANDBOX_FILE_SYMLINK, 0, 0};
+  return DoCall(&req, aOldPath, aNewPath, nullptr, false);
+}
+
+int
+SandboxBrokerClient::Rename(const char* aOldPath, const char* aNewPath)
+{
+  Request req = {SANDBOX_FILE_RENAME, 0, 0};
+  return DoCall(&req, aOldPath, aNewPath, nullptr, false);
+}
+
+int
+SandboxBrokerClient::Mkdir(const char* aPath, int aMode)
+{
+  Request req = {SANDBOX_FILE_MKDIR, aMode, 0};
+  return DoCall(&req, aPath, nullptr, nullptr, false);
+}
+
+int
+SandboxBrokerClient::Unlink(const char* aPath)
+{
+  Request req = {SANDBOX_FILE_UNLINK, 0, 0};
+  return DoCall(&req, aPath, nullptr, nullptr, false);
+}
+
+int
+SandboxBrokerClient::Rmdir(const char* aPath)
+{
+  Request req = {SANDBOX_FILE_RMDIR, 0, 0};
+  return DoCall(&req, aPath, nullptr, nullptr, false);
+}
+
+int
+SandboxBrokerClient::Readlink(const char* aPath, void* aBuff, size_t aSize)
+{
+  Request req = {SANDBOX_FILE_READLINK, 0, aSize};
+  return DoCall(&req, aPath, nullptr, aBuff, false);
+}
+
+} // namespace mozilla
+