[hackers] [sbase][PATCH] libutil: Fix buffer overflows in 224-bit SHA

From: Santtu Lakkala <inz_AT_inz.fi>
Date: Mon, 3 Nov 2025 17:46:05 +0200

Adjust buffer sizes for both SHA-256 and SHA-512 based 224-bit SHA
checksums.

Use a temporary buffer for SHA-512/224, as 224 is not multiple of 64-bit
internal state array of SHA-512.

---
 libutil/sha224.c     | 2 +-
 libutil/sha512-224.c | 5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/libutil/sha224.c b/libutil/sha224.c
index fce520f..3653b1c 100644
--- a/libutil/sha224.c
+++ b/libutil/sha224.c
_AT_@ -22,5 +22,5 @@ sha224_init(void *ctx)
 void
 sha224_sum(void *ctx, uint8_t md[SHA224_DIGEST_LENGTH])
 {
-	sha256_sum_n(ctx, md, 8);
+	sha256_sum_n(ctx, md, 7);
 }
diff --git a/libutil/sha512-224.c b/libutil/sha512-224.c
index a5636c1..959d0a8 100644
--- a/libutil/sha512-224.c
+++ b/libutil/sha512-224.c
_AT_@ -1,5 +1,6 @@
 /* public domain sha512/224 implementation based on fips180-3 */
 #include <stdint.h>
+#include <string.h>
 #include "../sha512-224.h"
 
 extern void sha512_sum_n(void *, uint8_t *, int n);
_AT_@ -22,5 +23,7 @@ sha512_224_init(void *ctx)
 void
 sha512_224_sum(void *ctx, uint8_t md[SHA512_224_DIGEST_LENGTH])
 {
-	sha512_sum_n(ctx, md, 4);
+	uint8_t buf[32];
+	sha512_sum_n(ctx, buf, 4);
+	memcpy(md, buf, SHA512_224_DIGEST_LENGTH);
 }
-- 
2.42.0

Received on Mon Nov 03 2025 - 16:46:05 CET