Even though these functions were exported, the number of applications
using them directly is very likely to be zero.
Still, bump the major library version to be safe and compliant.
This macro conflicts with other projects. This results in the inability to
build one DLL that depends on libsodium if the other DLL also uses the
DLL_EXPORT macro to control visibility of library symbols. Since the choice of
name for this macro is arbitrary, use of a library prefix is preferred.
ptr = sodium_malloc(size) returns a pointer from which exactly "size" bytes
can be accessed.
ptr = sodium_allocarray(count, size) allocates enough storage space for
"count" pointers or scalars of unit size "size".
In both cases, the region is immediately followed by a guard page.
As a result, any attempt to access a memory location after ptr[size - 1] will
immediately trigger a segmentation fault.
The allocated region is mlock()ed and filled with 0xd0 bytes.
A read-only page with the size, a guard page, as well as a canary are
placed before the returned pointer.
The canary is checked by sodium_free(); as a result, altering data right
before ptr is likely to cause sodium_free() to kill the process.
sodium_free() munlock()s the region and fills it with zeros before
actually calling free().
sodium_mprotect_noaccess(), sodium_mprotect_readonly() and
sodium_mprotect_readwrite() can be used to change the protection on the set
of allocated pages.
Reverting the protection to read+write is not required before calling
sodium_free().
