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/lib/stdlib/stdlib.mk b/lib/stdlib/stdlib.mk
index 4ff405f..5332717 100644
--- a/lib/stdlib/stdlib.mk
+++ b/lib/stdlib/stdlib.mk
@@ -42,7 +42,8 @@
strlen.c \
strncmp.c \
strnlen.c \
- subr_prf.c)
+ subr_prf.c \
+ timingsafe_bcmp.c)
INCLUDES += -Iinclude/lib/stdlib \
-Iinclude/lib/stdlib/sys