crypto: lib - make the sha1 library optional

Since the Linux RNG no longer uses sha1_transform(), the SHA-1 library is no longer needed unconditionally. Make it possible to build the Linux kernel without the SHA-1 library by putting it behind a kconfig option, and selecting this new option from the kconfig options that gate the remaining users: CRYPTO_SHA1 for crypto/sha1_generic.c, BPF for kernel/bpf/core.c, and IPV6 for net/ipv6/addrconf.c. Unfortunately, since BPF is selected by NET, for now this can only make a difference for kernels built without networking support. Signed-off-by: Eric Biggers <[email protected]> Reviewed-by: Jason A. Donenfeld <[email protected]> Acked-by: Jakub Kicinski <[email protected]> Acked-by: Alexei Starovoitov <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
niw · Jul 15, 2022 · ec8f7f4 · ec8f7f4
1 parent 463f740
commit ec8f7f4
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Showing 5 changed files with 8 additions and 1 deletion.
diff --git a/crypto/Kconfig b/crypto/Kconfig
@@ -901,6 +901,7 @@ config CRYPTO_RMD160
 config CRYPTO_SHA1
 	tristate "SHA1 digest algorithm"
 	select CRYPTO_HASH
+	select CRYPTO_LIB_SHA1
 	help
 	  SHA-1 secure hash standard (FIPS 180-1/DFIPS 180-2).
 

diff --git a/init/Kconfig b/init/Kconfig
@@ -1472,6 +1472,7 @@ config HAVE_PCSPKR_PLATFORM
 # interpreter that classic socket filters depend on
 config BPF
 	bool
+	select CRYPTO_LIB_SHA1
 
 menuconfig EXPERT
 	bool "Configure standard kernel features (expert users)"

diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig
@@ -121,6 +121,9 @@ config CRYPTO_LIB_CHACHA20POLY1305
 	select CRYPTO_LIB_POLY1305
 	select CRYPTO_ALGAPI
 
+config CRYPTO_LIB_SHA1
+	tristate
+
 config CRYPTO_LIB_SHA256
 	tristate
 

diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile
@@ -34,7 +34,8 @@ libpoly1305-y					:= poly1305-donna32.o
 libpoly1305-$(CONFIG_ARCH_SUPPORTS_INT128)	:= poly1305-donna64.o
 libpoly1305-y					+= poly1305.o
 
-obj-y						+= sha1.o
+obj-$(CONFIG_CRYPTO_LIB_SHA1)			+= libsha1.o
+libsha1-y					:= sha1.o
 
 obj-$(CONFIG_CRYPTO_LIB_SHA256)			+= libsha256.o
 libsha256-y					:= sha256.o

diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
@@ -7,6 +7,7 @@
 menuconfig IPV6
 	tristate "The IPv6 protocol"
 	default y
+	select CRYPTO_LIB_SHA1
 	help
 	  Support for IP version 6 (IPv6).