8 files changed, 21 insertions, 15 deletions
diff --git a/apt-pkg/contrib/hashes.cc b/apt-pkg/contrib/hashes.cc
index 755ad2035..662c2bf8b 100644
--- a/apt-pkg/contrib/hashes.cc
+++ b/apt-pkg/contrib/hashes.cc
@@ -312,6 +312,8 @@ public:
 // Hashes::Add* - Add the contents of data or FD			/*{{{*/
 bool Hashes::Add(const unsigned char * const Data, unsigned long long const Size)
 {
+   if (Size == 0)
+      return true;
    bool Res = true;
 APT_IGNORE_DEPRECATED_PUSH
    if ((d->CalcHashes & MD5SUM) == MD5SUM)
diff --git a/apt-pkg/contrib/hashes.h b/apt-pkg/contrib/hashes.h
index 9bfc32c54..1fe0afc00 100644
--- a/apt-pkg/contrib/hashes.h
+++ b/apt-pkg/contrib/hashes.h
@@ -195,11 +195,11 @@ class Hashes
 
    static const int UntilEOF = 0;
 
-   bool Add(const unsigned char * const Data, unsigned long long const Size);
-   APT_DEPRECATED_MSG("Construct accordingly instead of choosing hashes while adding") bool Add(const unsigned char * const Data, unsigned long long const Size, unsigned int const Hashes);
-   inline bool Add(const char * const Data)
+   bool Add(const unsigned char * const Data, unsigned long long const Size) APT_NONNULL(2);
+   APT_DEPRECATED_MSG("Construct accordingly instead of choosing hashes while adding") bool Add(const unsigned char * const Data, unsigned long long const Size, unsigned int const Hashes) APT_NONNULL(2);
+   inline bool Add(const char * const Data) APT_NONNULL(2)
    {return Add((unsigned char const * const)Data,strlen(Data));};
-   inline bool Add(const unsigned char * const Beg,const unsigned char * const End)
+   inline bool Add(const unsigned char * const Beg,const unsigned char * const End) APT_NONNULL(2,3)
    {return Add(Beg,End-Beg);};
 
    enum SupportedHashes { MD5SUM = (1 << 0), SHA1SUM = (1 << 1), SHA256SUM = (1 << 2),
diff --git a/apt-pkg/contrib/hashsum_template.h b/apt-pkg/contrib/hashsum_template.h
index 4000f230d..e5032d02f 100644
--- a/apt-pkg/contrib/hashsum_template.h
+++ b/apt-pkg/contrib/hashsum_template.h
@@ -122,18 +122,18 @@ class HashSumValue
 class SummationImplementation
 {
    public:
-   virtual bool Add(const unsigned char *inbuf, unsigned long long inlen) = 0;
-   inline bool Add(const char *inbuf, unsigned long long const inlen)
+   virtual bool Add(const unsigned char *inbuf, unsigned long long inlen) APT_NONNULL(2) = 0;
+   inline bool Add(const char *inbuf, unsigned long long const inlen) APT_NONNULL(2)
    { return Add((const unsigned char *)inbuf, inlen); }
 
-   inline bool Add(const unsigned char *Data)
+   inline bool Add(const unsigned char *Data) APT_NONNULL(2)
    { return Add(Data, strlen((const char *)Data)); }
-   inline bool Add(const char *Data)
+   inline bool Add(const char *Data) APT_NONNULL(2)
    { return Add((const unsigned char *)Data, strlen(Data)); }
 
-   inline bool Add(const unsigned char *Beg, const unsigned char *End)
+   inline bool Add(const unsigned char *Beg, const unsigned char *End) APT_NONNULL(2,3)
    { return Add(Beg, End - Beg); }
-   inline bool Add(const char *Beg, const char *End)
+   inline bool Add(const char *Beg, const char *End) APT_NONNULL(2,3)
    { return Add((const unsigned char *)Beg, End - Beg); }
 
    bool AddFD(int Fd, unsigned long long Size = 0);
diff --git a/apt-pkg/contrib/md5.cc b/apt-pkg/contrib/md5.cc
index b487a96f9..ff7868fe2 100644
--- a/apt-pkg/contrib/md5.cc
+++ b/apt-pkg/contrib/md5.cc
@@ -187,6 +187,8 @@ bool MD5Summation::Add(const unsigned char *data,unsigned long long len)
 {
    if (Done == true)
       return false;
+   if (len == 0)
+      return true;
 
    uint32_t *buf = (uint32_t *)Buf;
    uint32_t *bytes = (uint32_t *)Bytes;
diff --git a/apt-pkg/contrib/md5.h b/apt-pkg/contrib/md5.h
index a16ea4d2d..a286f092a 100644
--- a/apt-pkg/contrib/md5.h
+++ b/apt-pkg/contrib/md5.h
@@ -48,7 +48,7 @@ class MD5Summation : public SummationImplementation
 
    public:
 
-   bool Add(const unsigned char *inbuf, unsigned long long inlen) APT_OVERRIDE;
+   bool Add(const unsigned char *inbuf, unsigned long long inlen) APT_OVERRIDE APT_NONNULL(2);
    using SummationImplementation::Add;
 
    MD5SumValue Result();
diff --git a/apt-pkg/contrib/sha1.cc b/apt-pkg/contrib/sha1.cc
index bf6bc6cb6..298a7799b 100644
--- a/apt-pkg/contrib/sha1.cc
+++ b/apt-pkg/contrib/sha1.cc
@@ -243,6 +243,8 @@ bool SHA1Summation::Add(const unsigned char *data,unsigned long long len)
 {
    if (Done)
       return false;
+   if (len == 0)
+      return true;
 
    uint32_t *state = (uint32_t *)State;
    uint32_t *count = (uint32_t *)Count;
diff --git a/apt-pkg/contrib/sha1.h b/apt-pkg/contrib/sha1.h
index 1c5cb5aa1..3387c1cfd 100644
--- a/apt-pkg/contrib/sha1.h
+++ b/apt-pkg/contrib/sha1.h
@@ -37,7 +37,7 @@ class SHA1Summation : public SummationImplementation
    bool Done;
    
    public:
-   bool Add(const unsigned char *inbuf, unsigned long long inlen) APT_OVERRIDE;
+   bool Add(const unsigned char *inbuf, unsigned long long inlen) APT_OVERRIDE APT_NONNULL(2);
    using SummationImplementation::Add;
 
    SHA1SumValue Result();
diff --git a/apt-pkg/contrib/sha2.h b/apt-pkg/contrib/sha2.h
index 8b4bdd439..164840d3b 100644
--- a/apt-pkg/contrib/sha2.h
+++ b/apt-pkg/contrib/sha2.h
@@ -34,7 +34,7 @@ class SHA2SummationBase : public SummationImplementation
  protected:
    bool Done;
  public:
-   bool Add(const unsigned char *inbuf, unsigned long long len) APT_OVERRIDE = 0;
+   bool Add(const unsigned char *inbuf, unsigned long long len) APT_OVERRIDE APT_NONNULL(2) = 0;
 
    void Result();
 };
@@ -45,7 +45,7 @@ class SHA256Summation : public SHA2SummationBase
    unsigned char Sum[32];
 
    public:
-   bool Add(const unsigned char *inbuf, unsigned long long len) APT_OVERRIDE
+   bool Add(const unsigned char *inbuf, unsigned long long len) APT_OVERRIDE APT_NONNULL(2)
    {
       if (Done) 
          return false;
@@ -78,7 +78,7 @@ class SHA512Summation : public SHA2SummationBase
    unsigned char Sum[64];
 
    public:
-   bool Add(const unsigned char *inbuf, unsigned long long len) APT_OVERRIDE
+   bool Add(const unsigned char *inbuf, unsigned long long len) APT_OVERRIDE APT_NONNULL(2)
    {
       if (Done) 
          return false;