sha256/gcrypt: fix memory leak with SHA-256 repos

Eric Wong · gitster · commit 8b608f3fb843 · 2023-07-31T08:57:15.000-07:00
`gcry_md_open' needs to be paired with `gcry_md_close' to ensure
resources are released.  Since our internal APIs don't have
separate close/release callbacks, sticking it into the finalization
callback seems appropriate.

Building with SANITIZE=leak and running `git fsck' on a SHA-256
repository no longer reports leaks.

Signed-off-by: Eric Wong &lt;e@80x24.org&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/sha256/gcrypt.h b/sha256/gcrypt.h
@@ -20,6 +20,7 @@ static inline void gcrypt_SHA256_Update(gcrypt_SHA256_CTX *ctx, const void *data
 static inline void gcrypt_SHA256_Final(unsigned char *digest, gcrypt_SHA256_CTX *ctx)
 {
 	memcpy(digest, gcry_md_read(*ctx, GCRY_MD_SHA256), SHA256_DIGEST_SIZE);
+	gcry_md_close(*ctx);
 }
 
 static inline void gcrypt_SHA256_Clone(gcrypt_SHA256_CTX *dst, const gcrypt_SHA256_CTX *src)

Original file line number	Diff line number	Diff line change
`@@ -20,6 +20,7 @@ static inline void gcrypt_SHA256_Update(gcrypt_SHA256_CTX ctx, const void data`
`20`	`20`	`static inline void gcrypt_SHA256_Final(unsigned char digest, gcrypt_SHA256_CTX ctx)`
`21`	`21`	`{`
`22`	`22`	`memcpy(digest, gcry_md_read(*ctx, GCRY_MD_SHA256), SHA256_DIGEST_SIZE);`
	`23`	`+ gcry_md_close(*ctx);`
`23`	`24`	`}`
`24`	`25`
`25`	`26`	`static inline void gcrypt_SHA256_Clone(gcrypt_SHA256_CTX dst, const gcrypt_SHA256_CTX src)`