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authorDaniel Neus <[email protected]>2015-12-18 22:50:39 +0100
committerDaniel Neus <[email protected]>2015-12-18 22:50:39 +0100
commit3ebee37e0303d0a74c262153553d9905c847e5a9 (patch)
treea9e61c4b86ee7f7a6edf82a10f22b472d1584f98 /src/lib
parent56af160c9d4df53467ce742e2ba9b9f512fb7c83 (diff)
add support for Intel RdSeed
Diffstat (limited to 'src/lib')
-rw-r--r--src/lib/entropy/entropy_srcs.cpp11
-rw-r--r--src/lib/entropy/rdseed/info.txt23
-rw-r--r--src/lib/entropy/rdseed/rdseed.cpp56
-rw-r--r--src/lib/entropy/rdseed/rdseed.h28
4 files changed, 118 insertions, 0 deletions
diff --git a/src/lib/entropy/entropy_srcs.cpp b/src/lib/entropy/entropy_srcs.cpp
index cbf13d488..a5dc0a819 100644
--- a/src/lib/entropy/entropy_srcs.cpp
+++ b/src/lib/entropy/entropy_srcs.cpp
@@ -15,6 +15,10 @@
#include <botan/internal/rdrand.h>
#endif
+#if defined(BOTAN_HAS_ENTROPY_SRC_RDSEED)
+ #include <botan/internal/rdseed.h>
+#endif
+
#if defined(BOTAN_HAS_ENTROPY_SRC_DEV_RANDOM)
#include <botan/internal/dev_random.h>
#endif
@@ -64,6 +68,13 @@ std::unique_ptr<Entropy_Source> Entropy_Source::create(const std::string& name)
return std::unique_ptr<Entropy_Source>(new Intel_Rdrand);
#endif
}
+
+ if(name == "rdseed")
+ {
+#if defined(BOTAN_HAS_ENTROPY_SRC_RDSEED)
+ return std::unique_ptr<Entropy_Source>(new Intel_Rdseed);
+#endif
+ }
if(name == "proc_info")
{
diff --git a/src/lib/entropy/rdseed/info.txt b/src/lib/entropy/rdseed/info.txt
new file mode 100644
index 000000000..53aa496b0
--- /dev/null
+++ b/src/lib/entropy/rdseed/info.txt
@@ -0,0 +1,23 @@
+define ENTROPY_SRC_RDSEED 20151218
+
+need_isa rdseed
+
+<source>
+rdseed.cpp
+</source>
+
+<header:internal>
+rdseed.h
+</header:internal>
+
+<arch>
+x86_32
+x86_64
+</arch>
+
+<cc>
+gcc
+clang
+icc
+msvc
+</cc>
diff --git a/src/lib/entropy/rdseed/rdseed.cpp b/src/lib/entropy/rdseed/rdseed.cpp
new file mode 100644
index 000000000..8bdd79a1d
--- /dev/null
+++ b/src/lib/entropy/rdseed/rdseed.cpp
@@ -0,0 +1,56 @@
+/*
+* Entropy Source Using Intel's rdseed instruction
+* (C) 2015 Jack Lloyd, Daniel Neus
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/internal/rdseed.h>
+#include <botan/cpuid.h>
+
+#if !defined(BOTAN_USE_GCC_INLINE_ASM)
+ #include <immintrin.h>
+#endif
+
+namespace Botan {
+
+/*
+* Get the timestamp
+*/
+void Intel_Rdseed::poll(Entropy_Accumulator& accum)
+ {
+ if(!CPUID::has_rdseed())
+ return;
+
+ /*
+ Don't consider rdseed as contributing any entropy to the poll. It doesn't
+ make sense to trust uninspectible hardware.
+
+ Even if backdoored, rdseed cannot harm us because the HMAC_RNG poll process
+ is designed to handle arbitrarily large amounts of attacker known/chosen
+ input (or even a reseed where every bit we reseeded with was attacker chosen),
+ as long as at least one seed occurred with enough unknown-to-attacker entropy.
+ */
+ const double ENTROPY_ESTIMATE = 0.0;
+ const size_t RDSEED_POLLS = 32;
+
+ for(size_t i = 0; i != RDSEED_POLLS; ++i)
+ {
+ unsigned int r = 0;
+
+#if defined(BOTAN_USE_GCC_INLINE_ASM)
+ int cf = 0;
+
+ // Encoding of rdseed %eax
+ asm(".byte 0x0F, 0xC7, 0xF8; adcl $0,%1" :
+ "=a" (r), "=r" (cf) : "0" (r), "1" (cf) : "cc");
+#else
+ int cf = _rdseed32_step(&r);
+#endif
+
+ if(cf == 1)
+ accum.add(r, ENTROPY_ESTIMATE);
+ }
+ }
+
+}
diff --git a/src/lib/entropy/rdseed/rdseed.h b/src/lib/entropy/rdseed/rdseed.h
new file mode 100644
index 000000000..0f39250a1
--- /dev/null
+++ b/src/lib/entropy/rdseed/rdseed.h
@@ -0,0 +1,28 @@
+/*
+* Entropy Source Using Intel's rdseed instruction
+* (C) 2015 Jack Lloyd, Daniel Neus
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_ENTROPY_SRC_RDSEED_H__
+#define BOTAN_ENTROPY_SRC_RDSEED_H__
+
+#include <botan/entropy_src.h>
+
+namespace Botan {
+
+/**
+* Entropy source using the rdseed instruction first introduced on
+* Intel's Broadwell architecture.
+*/
+class Intel_Rdseed : public Entropy_Source
+ {
+ public:
+ std::string name() const override { return "rdseed"; }
+ void poll(Entropy_Accumulator& accum) override;
+ };
+
+}
+
+#endif