1 files changed, 54 insertions, 3 deletions

diff --git a/src/libsodium/include/sodium/utils.h b/src/libsodium/include/sodium/utils.h
index 817919b..1ac78eb 100644
--- a/src/libsodium/include/sodium/utils.h
+++ b/src/libsodium/include/sodium/utils.h
@@ -16,12 +16,14 @@ extern "C" {
 # define _SODIUM_C99(X) X
 #endif
 
-unsigned char *_sodium_alignedcalloc(unsigned char ** const unaligned_p,
-                                     const size_t len);
-
 SODIUM_EXPORT
 void sodium_memzero(void * const pnt, const size_t len);
 
+/* WARNING: sodium_memcmp() must be used to verify if two secret keys
+ * are equal, in constant time.
+ * It returns 0 if the keys are equal, and -1 if they differ.
+ * This function is not designed for lexicographical comparisons.
+ */
 SODIUM_EXPORT
 int sodium_memcmp(const void * const b1_, const void * const b2_, size_t len);
 
@@ -41,6 +43,55 @@ int sodium_mlock(void * const addr, const size_t len);
 SODIUM_EXPORT
 int sodium_munlock(void * const addr, const size_t len);
 
+/* WARNING: sodium_malloc() and sodium_allocarray() are not general-purpose
+ * allocation functions.
+ *
+ * They return a pointer to a region filled with 0xd0 bytes, immediately
+ * followed by a guard page.
+ * As a result, accessing a single byte after the requested allocation size
+ * will intentionally trigger a segmentation fault.
+ *
+ * A canary and an additional guard page placed before the beginning of the
+ * region may also kill the process if a buffer underflow is detected.
+ *
+ * The memory layout is:
+ * [unprotected region size (read only)][guard page (no access)][unprotected pages (read/write)][guard page (no access)]
+ * With the layout of the unprotected pages being:
+ * [optional padding][16-bytes canary][user region]
+ *
+ * However:
+ * - These functions are significantly slower than standard functions
+ * - Each allocation requires 3 or 4 additional pages
+ * - The returned address will not be aligned if the allocation size is not
+ *   a multiple of the required alignment. For this reason, these functions
+ *   are designed to store data, such as secret keys and messages.
+ *   They should not be used to store pointers mixed with other types
+ *   in portable code unless extreme care is taken to ensure correct
+ *   pointers alignment.
+ */
+
+SODIUM_EXPORT
+void *sodium_malloc(const size_t size);
+
+SODIUM_EXPORT
+void *sodium_allocarray(size_t count, size_t size);
+
+SODIUM_EXPORT
+void sodium_free(void *ptr);
+
+SODIUM_EXPORT
+int sodium_mprotect_noaccess(void *ptr);
+
+SODIUM_EXPORT
+int sodium_mprotect_readonly(void *ptr);
+
+SODIUM_EXPORT
+int sodium_mprotect_readwrite(void *ptr);
+
+/* -------- */
+
+int _sodium_alloc_init(void);
+
 #ifdef __cplusplus
 }
 #endif