t0013: add a basic sha1 collision detection test

diff --git a/Makefile b/Makefile
index 25c21f08b185325c7e6845baf62460f7865f478c..fc9d89498b47d9ca7ae07b2fdef7563d95a67465 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -142,6 +142,10 @@ all::
 # Define PPC_SHA1 environment variable when running make to make use of
 # a bundled SHA1 routine optimized for PowerPC.
 #
+# Define DC_SHA1 to unconditionally enable the collision-detecting sha1
+# algorithm. This is slower, but may detect attempted collision attacks.
+# Takes priority over other *_SHA1 knobs.
+#
 # Define SHA1_MAX_BLOCK_SIZE to limit the amount of data that will be hashed
 # in one call to the platform's SHA1_Update(). e.g. APPLE_COMMON_CRYPTO
 # wants 'SHA1_MAX_BLOCK_SIZE=1024L*1024L*1024L' defined.
@@ -1386,6 +1390,11 @@ ifdef APPLE_COMMON_CRYPTO
        SHA1_MAX_BLOCK_SIZE = 1024L*1024L*1024L
 endif
 
+ifdef DC_SHA1
+       LIB_OBJS += sha1dc/sha1.o
+       LIB_OBJS += sha1dc/ubc_check.o
+       BASIC_CFLAGS += -DSHA1_DC
+else
 ifdef BLK_SHA1
        LIB_OBJS += block-sha1/sha1.o
        BASIC_CFLAGS += -DSHA1_BLK
@@ -1403,6 +1412,7 @@ else
 endif
 endif
 endif
+endif
 
 ifdef SHA1_MAX_BLOCK_SIZE
        LIB_OBJS += compat/sha1-chunked.o
@@ -2226,6 +2236,7 @@ GIT-BUILD-OPTIONS: FORCE
        @echo NO_PYTHON=\''$(subst ','\'',$(subst ','\'',$(NO_PYTHON)))'\' >>$@+
        @echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@+
        @echo PAGER_ENV=\''$(subst ','\'',$(subst ','\'',$(PAGER_ENV)))'\' >>$@+
+       @echo DC_SHA1=\''$(subst ','\'',$(subst ','\'',$(DC_SHA1)))'\' >>$@+
 ifdef TEST_OUTPUT_DIRECTORY
        @echo TEST_OUTPUT_DIRECTORY=\''$(subst ','\'',$(subst ','\'',$(TEST_OUTPUT_DIRECTORY)))'\' >>$@+
 endif