From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Fri, 23 Mar 2018 16:11:43 +0000 (+0100)
Subject: Use obj.data() instead of &obj.at(0) to prevent exception
X-Git-Tag: dnsdist-1.3.0~31^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c2a16005ce822b3d704d2e717d734ee94e4ed189;p=thirdparty%2Fpdns.git

Use obj.data() instead of &obj.at(0) to prevent exception

In case of a 0-sized container, &obj.at(0) would throw an exception
even if we don't intend to use the pointer afterward.
obj.data is required to provide a non-nullptr pointer that we should
not dereference for most containers (except strings since C++11),
but that's fine for the way we intend (not to) use it.
---

diff --git a/modules/pipebackend/coprocess.cc b/modules/pipebackend/coprocess.cc
index 029a8b8dac..f3967301d0 100644
--- a/modules/pipebackend/coprocess.cc
+++ b/modules/pipebackend/coprocess.cc
@@ -51,7 +51,7 @@ CoProcess::CoProcess(const string &command,int timeout, int infd, int outfd)
   for (size_t n = 0; n < v.size(); n++)
     argv[n]=v[n].c_str();
   // we get away with not copying since nobody resizes v 
-  launch(&argv.at(0), timeout, infd, outfd);
+  launch(argv.data(), timeout, infd, outfd);
 }
 
 void CoProcess::launch(const char **argv, int timeout, int infd, int outfd)
diff --git a/modules/remotebackend/pipeconnector.cc b/modules/remotebackend/pipeconnector.cc
index ba3aaba9a4..b7fd605ee5 100644
--- a/modules/remotebackend/pipeconnector.cc
+++ b/modules/remotebackend/pipeconnector.cc
@@ -107,7 +107,7 @@ void PipeConnector::launch() {
 
     // stdin & stdout are now connected, fire up our coprocess!
 
-    if(execv(argv[0], const_cast<char * const *>(&argv[0]))<0) // now what
+    if(execv(argv[0], const_cast<char * const *>(argv.data()))<0) // now what
       exit(123);
 
     /* not a lot we can do here. We shouldn't return because that will leave a forked process around.
diff --git a/pdns/dnsdist-tcp.cc b/pdns/dnsdist-tcp.cc
index 124745f54c..91ee527c40 100644
--- a/pdns/dnsdist-tcp.cc
+++ b/pdns/dnsdist-tcp.cc
@@ -561,7 +561,7 @@ void* tcpClientThread(int pipefd)
 #endif
         responseSize += addRoom;
         answerBuffer.resize(responseSize);
-        char* response = &answerBuffer.at(0);
+        char* response = answerBuffer.data();
         readn2WithTimeout(dsock, response, rlen, ds->tcpRecvTimeout);
         uint16_t responseLen = rlen;
         if (outstanding) {
diff --git a/pdns/misc.cc b/pdns/misc.cc
index 11d31f4e85..78ec742b9b 100644
--- a/pdns/misc.cc
+++ b/pdns/misc.cc
@@ -363,7 +363,7 @@ int waitForMultiData(const set<int>& fds, const int seconds, const int useconds,
   }
 
   std::vector<struct pollfd> pfds(realFDs.size());
-  memset(&pfds.at(0), 0, realFDs.size()*sizeof(struct pollfd));
+  memset(pfds.data(), 0, realFDs.size()*sizeof(struct pollfd));
   int ctr = 0;
   for (const auto& fd : realFDs) {
     pfds[ctr].fd = fd;
@@ -373,9 +373,9 @@ int waitForMultiData(const set<int>& fds, const int seconds, const int useconds,
 
   int ret;
   if(seconds >= 0)
-    ret = poll(&pfds.at(0), realFDs.size(), seconds * 1000 + useconds/1000);
+    ret = poll(pfds.data(), realFDs.size(), seconds * 1000 + useconds/1000);
   else
-    ret = poll(&pfds.at(0), realFDs.size(), -1);
+    ret = poll(pfds.data(), realFDs.size(), -1);
   if(ret <= 0)
     return ret;
 
diff --git a/pdns/opensslsigners.cc b/pdns/opensslsigners.cc
index 3176744d45..daff5a5384 100644
--- a/pdns/opensslsigners.cc
+++ b/pdns/opensslsigners.cc
@@ -388,14 +388,14 @@ std::string OpenSSLRSADNSCryptoKeyEngine::getPubKeyHash() const
     throw runtime_error(getName()+" failed to init hash context for generating the public key hash");
   }
 
-  int len = BN_bn2bin(e, &tmp.at(0));
-  res = SHA1_Update(&ctx, &tmp.at(0), len);
+  int len = BN_bn2bin(e, tmp.data());
+  res = SHA1_Update(&ctx, tmp.data(), len);
   if (res != 1) {
     throw runtime_error(getName()+" failed to update hash context for generating the public key hash");
   }
 
-  len = BN_bn2bin(n, &tmp.at(0));
-  res = SHA1_Update(&ctx, &tmp.at(0), len);
+  len = BN_bn2bin(n, tmp.data());
+  res = SHA1_Update(&ctx, tmp.data(), len);
   if (res != 1) {
     throw runtime_error(getName()+" failed to update hash context for generating the public key hash");
   }
diff --git a/pdns/pkcs11signers.cc b/pdns/pkcs11signers.cc
index 4ad764c488..041cb8c177 100644
--- a/pdns/pkcs11signers.cc
+++ b/pdns/pkcs11signers.cc
@@ -673,7 +673,7 @@ CK_RV Pkcs11Slot::HuntSlot(const string& tokenId, CK_SLOT_ID &slotId, _CK_SLOT_I
 
   // get the actual slot ids
   std::vector<CK_SLOT_ID> slotIds(slots);
-  err = functions->C_GetSlotList(CK_FALSE, &slotIds.at(0), &slots);
+  err = functions->C_GetSlotList(CK_FALSE, slotIds.data(), &slots);
   if (err) {
     L<<Logger::Warning<<"C_GetSlotList(CK_FALSE, slotIds, &slots) = " << err << std::endl;
     return err;
diff --git a/pdns/sodcrypto.cc b/pdns/sodcrypto.cc
index daff010ff6..2bdf5beaf2 100644
--- a/pdns/sodcrypto.cc
+++ b/pdns/sodcrypto.cc
@@ -62,7 +62,7 @@ std::string sodDecryptSym(const std::string& msg, const std::string& key, Sodium
 
   decrypted.resize(msg.length() - crypto_secretbox_MACBYTES);
 
-  if (crypto_secretbox_open_easy(reinterpret_cast<unsigned char*>(&decrypted.at(0)),
+  if (crypto_secretbox_open_easy(reinterpret_cast<unsigned char*>(const_cast<char *>(decrypted.data())),
                                  reinterpret_cast<const unsigned char*>(msg.c_str()),
                                  msg.length(),
                                  nonce.value,