crypto: vmac - remove unused VMAC algorithm

Remove the vmac64 template, as it has no known users.  It also continues
to have longstanding bugs such as alignment violations (see
https://lore.kernel.org/r/20241226134847.6690-1-evepolonium@gmail.com/).

This code was added in 2009 by commit f1939f7c5645 ("crypto: vmac - New
hash algorithm for intel_txt support").  Based on the mention of
intel_txt support in the commit title, it seems it was added as a
prerequisite for the contemporaneous patch
"intel_txt: add s3 userspace memory integrity verification"
(https://lore.kernel.org/r/4ABF2B50.6070106@intel.com/).  In the design
proposed by that patch, when an Intel Trusted Execution Technology (TXT)
enabled system resumed from suspend, the "tboot" trusted executable
launched the Linux kernel without verifying userspace memory, and then
the Linux kernel used VMAC to verify userspace memory.

However, that patch was never merged, as reviewers had objected to the
design.  It was later reworked into commit 4bd96a7a8185 ("x86, tboot:
Add support for S3 memory integrity protection") which made tboot verify
the memory instead.  Thus the VMAC support in Linux was never used.

No in-tree user has appeared since then, other than potentially the
usual components that allow specifying arbitrary hash algorithms by
name, namely AF_ALG and dm-integrity.  However there are no indications
that VMAC is being used with these components.  Debian Code Search and
web searches for "vmac64" (the actual algorithm name) do not return any
results other than the kernel itself, suggesting that it does not appear
in any other code or documentation.  Explicitly grepping the source code
of the usual suspects (libell, iwd, cryptsetup) finds no matches either.

Before 2018, the vmac code was also completely broken due to using a
hardcoded nonce and the wrong endianness for the MAC.  It was then fixed
by commit ed331adab35b ("crypto: vmac - add nonced version with big
endian digest") and commit 0917b873127c ("crypto: vmac - remove insecure
version with hardcoded nonce").  These were intentionally breaking
changes that changed all the computed MAC values as well as the
algorithm name ("vmac" to "vmac64").  No complaints were ever received
about these breaking changes, strongly suggesting the absence of users.

The reason I had put some effort into fixing this code in 2018 is
because it was used by an out-of-tree driver.  But if it is still needed
in that particular out-of-tree driver, the code can be carried in that
driver instead.  There is no need to carry it upstream.

Cc: Atharva Tiwari <evepolonium@gmail.com>
Cc: Shane Wang <shane.wang@intel.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> # m68k
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

12 files changed, 0 insertions, 12 deletions

diff --git a/arch/m68k/configs/amiga_defconfig b/arch/m68k/configs/amiga_defconfig
index c705247e7b5b..5f9117b46867 100644
--- a/arch/m68k/configs/amiga_defconfig
+++ b/arch/m68k/configs/amiga_defconfig
@@ -589,7 +589,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/apollo_defconfig b/arch/m68k/configs/apollo_defconfig
index 6d62b9187a58..eb8a0432f1fa 100644
--- a/arch/m68k/configs/apollo_defconfig
+++ b/arch/m68k/configs/apollo_defconfig
@@ -546,7 +546,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/atari_defconfig b/arch/m68k/configs/atari_defconfig
index c3c644df852d..8ac95c1207b1 100644
--- a/arch/m68k/configs/atari_defconfig
+++ b/arch/m68k/configs/atari_defconfig
@@ -566,7 +566,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/bvme6000_defconfig b/arch/m68k/configs/bvme6000_defconfig
index 20261f819691..cf9ea62bdcbe 100644
--- a/arch/m68k/configs/bvme6000_defconfig
+++ b/arch/m68k/configs/bvme6000_defconfig
@@ -538,7 +538,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/hp300_defconfig b/arch/m68k/configs/hp300_defconfig
index ce4fe93a0f70..aacb040b741e 100644
--- a/arch/m68k/configs/hp300_defconfig
+++ b/arch/m68k/configs/hp300_defconfig
@@ -548,7 +548,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/mac_defconfig b/arch/m68k/configs/mac_defconfig
index 040ae75f47c3..2b0383580564 100644
--- a/arch/m68k/configs/mac_defconfig
+++ b/arch/m68k/configs/mac_defconfig
@@ -565,7 +565,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/multi_defconfig b/arch/m68k/configs/multi_defconfig
index 20d877cb4e30..3d0b5af6bb60 100644
--- a/arch/m68k/configs/multi_defconfig
+++ b/arch/m68k/configs/multi_defconfig
@@ -652,7 +652,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/mvme147_defconfig b/arch/m68k/configs/mvme147_defconfig
index 5e1c8d0d3da5..ee0f2fbd7fbf 100644
--- a/arch/m68k/configs/mvme147_defconfig
+++ b/arch/m68k/configs/mvme147_defconfig
@@ -538,7 +538,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/mvme16x_defconfig b/arch/m68k/configs/mvme16x_defconfig
index 5d1409e6a137..cac90de4f3e7 100644
--- a/arch/m68k/configs/mvme16x_defconfig
+++ b/arch/m68k/configs/mvme16x_defconfig
@@ -539,7 +539,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/q40_defconfig b/arch/m68k/configs/q40_defconfig
index e4c30e2b9bbb..5301fc6fbd37 100644
--- a/arch/m68k/configs/q40_defconfig
+++ b/arch/m68k/configs/q40_defconfig
@@ -555,7 +555,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/sun3_defconfig b/arch/m68k/configs/sun3_defconfig
index 980843a9ea1e..1002082c0b5e 100644
--- a/arch/m68k/configs/sun3_defconfig
+++ b/arch/m68k/configs/sun3_defconfig
@@ -536,7 +536,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m
diff --git a/arch/m68k/configs/sun3x_defconfig b/arch/m68k/configs/sun3x_defconfig
index 38681cc6b598..65c80b7188fd 100644
--- a/arch/m68k/configs/sun3x_defconfig
+++ b/arch/m68k/configs/sun3x_defconfig
@@ -536,7 +536,6 @@ CONFIG_CRYPTO_MD4=m
 CONFIG_CRYPTO_MICHAEL_MIC=m
 CONFIG_CRYPTO_RMD160=m
 CONFIG_CRYPTO_SM3_GENERIC=m
-CONFIG_CRYPTO_VMAC=m
 CONFIG_CRYPTO_WP512=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_LZO=m