stdlib: Import timingsafe_bcmp() from FreeBSD
Some side-channel attacks involve an attacker inferring something from
the time taken for a memory compare operation to complete, for example
when comparing hashes during image authentication. To mitigate this,
timingsafe_bcmp() must be used for such operations instead of the
standard memcmp().
This function executes in constant time and so doesn't leak any timing
information to the caller.
Change-Id: I470a723dc3626a0ee6d5e3f7fd48d0a57b8aa5fd
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/include/lib/stdlib/string.h b/include/lib/stdlib/string.h
index 9beeb44..902d9c1 100644
--- a/include/lib/stdlib/string.h
+++ b/include/lib/stdlib/string.h
@@ -61,6 +61,7 @@
int strncmp(const char *, const char *, size_t) __pure;
size_t strnlen(const char *, size_t) __pure;
int strcasecmp(const char *, const char *);
+int timingsafe_bcmp(const void *, const void *, size_t);
__END_DECLS