[PATCH v1 0/2] crypto: Fix sha1 compile error

[PATCH v1 0/2] crypto: Fix sha1 compile error

[Yuzhuo Jing]

This is a followup patch series for an ongoing patch series to reuse
kernel tree sha1 utils in perf tools and remove libcrypto dependency.
This mirrors the fixes made in perf back to the kernel tree so we can
use tools/perf/check-headers.sh to monitor future changes.
Link: https://lore.kernel.org/lkml/aC9lXhPFcs5fkHWH@x1/t/#u

This series contains two patches: one fixing signed and unsigned integer
comparisons and another fixing function type mismatches.

Yuzhuo Jing (2):
  crypto: Fix sha1 signed integer comparison compile error
  crypto: Fix sha1 signed pointer comparison compile error

 crypto/sha1_generic.c      | 2 +-
 include/crypto/sha1_base.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

-- 
2.50.0.rc1.591.g9c95f17f64-goog

[PATCH v1 1/2] crypto: Fix sha1 signed integer comparison compile error

[Yuzhuo Jing]

On platforms where -Werror=sign-compare compiler flag is enabled, sha1
code gives errors when for signed to unsigned integer comparisons.
This patch fixes the issue.

Signed-off-by: Yuzhuo Jing <yuzhuo@google.com>
---
 include/crypto/sha1_base.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/crypto/sha1_base.h b/include/crypto/sha1_base.h
index 0c342ed0d038..3460759d31db 100644
--- a/include/crypto/sha1_base.h
+++ b/include/crypto/sha1_base.h
@@ -73,7 +73,7 @@ static inline int sha1_base_do_update(struct shash_desc *desc,
 static inline int sha1_base_do_finalize(struct shash_desc *desc,
 					sha1_block_fn *block_fn)
 {
-	const int bit_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
+	const unsigned int bit_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
 	struct sha1_state *sctx = shash_desc_ctx(desc);
 	__be64 *bits = (__be64 *)(sctx->buffer + bit_offset);
 	unsigned int partial = sctx->count % SHA1_BLOCK_SIZE;
@@ -99,7 +99,7 @@ static inline int sha1_base_finish(struct shash_desc *desc, u8 *out)
 	__be32 *digest = (__be32 *)out;
 	int i;
 
-	for (i = 0; i < SHA1_DIGEST_SIZE / sizeof(__be32); i++)
+	for (i = 0; i < SHA1_DIGEST_SIZE / (int)sizeof(__be32); i++)
 		put_unaligned_be32(sctx->state[i], digest++);
 
 	memzero_explicit(sctx, sizeof(*sctx));
-- 
2.50.0.rc1.591.g9c95f17f64-goog

[PATCH v1 2/2] crypto: Fix sha1 signed pointer comparison compile error

[Yuzhuo Jing]

In include/crypto/sha1_base.h, sha1_block_fn type is defined as
void(sha1_block_fn)(struct sha1_state *sst, u8 const *src, int blocks);

In lib/crypto/sha1.c, the second argument on sha1_transform is defined
as "const char *", which causes type mismatch when calling
sha1_transform from sha1_generic_block_fn in crypto/sha1_generic.c.

We don't break the widely used sha1_block_fn or sha1_transform function
signatures, so this patch converts the pointer sign at usage to fix the
compile error for environments that enable -Werror=pointer-sign.

Signed-off-by: Yuzhuo Jing <yuzhuo@google.com>
---
 crypto/sha1_generic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crypto/sha1_generic.c b/crypto/sha1_generic.c
index 325b57fe28dc..3a3f9608b989 100644
--- a/crypto/sha1_generic.c
+++ b/crypto/sha1_generic.c
@@ -33,7 +33,7 @@ static void sha1_generic_block_fn(struct sha1_state *sst, u8 const *src,
 	u32 temp[SHA1_WORKSPACE_WORDS];
 
 	while (blocks--) {
-		sha1_transform(sst->state, src, temp);
+		sha1_transform(sst->state, (const char *)src, temp);
 		src += SHA1_BLOCK_SIZE;
 	}
 	memzero_explicit(temp, sizeof(temp));
-- 
2.50.0.rc1.591.g9c95f17f64-goog

Re: [PATCH v1 0/2] crypto: Fix sha1 compile error

[Eric Biggers]

On Fri, Jun 13, 2025 at 05:08:26PM -0700, Yuzhuo Jing wrote:
> This is a followup patch series for an ongoing patch series to reuse
> kernel tree sha1 utils in perf tools and remove libcrypto dependency.
> This mirrors the fixes made in perf back to the kernel tree so we can
> use tools/perf/check-headers.sh to monitor future changes.
> Link: https://lore.kernel.org/lkml/aC9lXhPFcs5fkHWH@x1/t/#u
> 
> This series contains two patches: one fixing signed and unsigned integer
> comparisons and another fixing function type mismatches.
> 
> Yuzhuo Jing (2):
>   crypto: Fix sha1 signed integer comparison compile error
>   crypto: Fix sha1 signed pointer comparison compile error
> 
>  crypto/sha1_generic.c      | 2 +-
>  include/crypto/sha1_base.h | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)

I don't like these signedness inconsistencies in the code either, and I'll be
fixing these (among many other issues) when I refactor SHA-1 to have a proper
lib/crypto/ API similar to what I'm currently doing with SHA-2.  That being
said, the kernel doesn't have these warnings enabled, and especially in its
current state this code isn't really designed to be copied into a userspace
program.

So I feel that the premise of this patchset, and more importantly also the one
you linked to above for tools/perf/, is a bit misguided.

I've sent an alternative patchset for you to consider:
https://lore.kernel.org/all/20250614044133.660848-1-ebiggers@kernel.org/.  It
adds a minimal SHA-1 implementation, including a test, to tools/perf/util/.  The
SHA-1 implementation is less than 100 lines anyway.

The effort it would take to "share" the kernel's code here is just not worth it,
IMO.  Especially when I have some significant refactoring planned on the kernel
side which would make the tools/perf copy diverge anyway.

- Eric