diff options
Diffstat (limited to 'src/support')
-rw-r--r-- | src/support/cleanse.cpp | 30 | ||||
-rw-r--r-- | src/support/lockedpool.h | 12 |
2 files changed, 34 insertions, 8 deletions
diff --git a/src/support/cleanse.cpp b/src/support/cleanse.cpp index a2141b2449..95899c9f02 100644 --- a/src/support/cleanse.cpp +++ b/src/support/cleanse.cpp @@ -5,9 +5,35 @@ #include "cleanse.h" -#include <openssl/crypto.h> +#include <cstring> +/* Compilers have a bad habit of removing "superfluous" memset calls that + * are trying to zero memory. For example, when memset()ing a buffer and + * then free()ing it, the compiler might decide that the memset is + * unobservable and thus can be removed. + * + * Previously we used OpenSSL which tried to stop this by a) implementing + * memset in assembly on x86 and b) putting the function in its own file + * for other platforms. + * + * This change removes those tricks in favour of using asm directives to + * scare the compiler away. As best as our compiler folks can tell, this is + * sufficient and will continue to be so. + * + * Adam Langley <agl@google.com> + * Commit: ad1907fe73334d6c696c8539646c21b11178f20f + * BoringSSL (LICENSE: ISC) + */ void memory_cleanse(void *ptr, size_t len) { - OPENSSL_cleanse(ptr, len); + std::memset(ptr, 0, len); + + /* As best as we can tell, this is sufficient to break any optimisations that + might try to eliminate "superfluous" memsets. If there's an easy way to + detect memset_s, it would be better to use that. */ +#if defined(_MSC_VER) + __asm; +#else + __asm__ __volatile__("" : : "r"(ptr) : "memory"); +#endif } diff --git a/src/support/lockedpool.h b/src/support/lockedpool.h index cecbdec1aa..834f0371e2 100644 --- a/src/support/lockedpool.h +++ b/src/support/lockedpool.h @@ -50,6 +50,9 @@ public: Arena(void *base, size_t size, size_t alignment); virtual ~Arena(); + Arena(const Arena& other) = delete; // non construction-copyable + Arena& operator=(const Arena&) = delete; // non copyable + /** Memory statistics. */ struct Stats { @@ -85,9 +88,6 @@ public: */ bool addressInArena(void *ptr) const { return ptr >= base && ptr < end; } private: - Arena(const Arena& other) = delete; // non construction-copyable - Arena& operator=(const Arena&) = delete; // non copyable - /** Map of chunk address to chunk information. This class makes use of the * sorted order to merge previous and next chunks during deallocation. */ @@ -153,6 +153,9 @@ public: explicit LockedPool(std::unique_ptr<LockedPageAllocator> allocator, LockingFailed_Callback lf_cb_in = nullptr); ~LockedPool(); + LockedPool(const LockedPool& other) = delete; // non construction-copyable + LockedPool& operator=(const LockedPool&) = delete; // non copyable + /** Allocate size bytes from this arena. * Returns pointer on success, or 0 if memory is full or * the application tried to allocate 0 bytes. @@ -168,9 +171,6 @@ public: /** Get pool usage statistics */ Stats stats() const; private: - LockedPool(const LockedPool& other) = delete; // non construction-copyable - LockedPool& operator=(const LockedPool&) = delete; // non copyable - std::unique_ptr<LockedPageAllocator> allocator; /** Create an arena from locked pages */ |