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crypto: s390/sha - Fix uninitialized variable in SHA-1 and SHA-2

PATCH New Eric Biggers 1 participant 1 message Jul 3, 2025

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Stable branch Crypto API s390 s390 crypto modules, prng driver, arch random
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Eric Biggers

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PATCH v2 1/1 crypto: s390/sha - Fix uninitialized variable in SHA-1 and SHA-2

Commit 88c02b3f79a6 ("s390/sha3: Support sha3 performance enhancements") added the field s390_sha_ctx::first_message_part and made it be used by s390_sha_update() (now s390_sha_update_blocks()). At the time, s390_sha_update() was used by all the s390 SHA-1, SHA-2, and SHA-3 algorithms. However, only the initialization functions for SHA-3 were updated, leaving SHA-1 and SHA-2 using first_message_part uninitialized.

This could cause e.g. the function code CPACF_KIMD_SHA_512 | CPACF_KIMD_NIP to be used instead of just CPACF_KIMD_SHA_512. This apparently was harmless, as the SHA-1 and SHA-2 function codes ignore CPACF_KIMD_NIP; it is recognized only by the SHA-3 function codes
(https://lore.kernel.org/r/[email protected]/).
Therefore, this bug was found only when first_message_part was later converted to a boolean and UBSAN detected its uninitialized use. Regardless, let's fix this by just initializing to zero.

Note: in 6.16, we need to patch SHA-1, SHA-384, and SHA-512. In 6.15 and earlier, we'll also need to patch SHA-224 and SHA-256, as they hadn't yet been librarified (which incidentally fixed this bug).

Fixes 88c02b3f79a6 ("s390/sha3: Support sha3 performance enhancements")
Cc [email protected]
Reported-by Ingo Franzki <[email protected]>
Closes https://lore.kernel.org/r/[email protected] open here
Acked-by Heiko Carstens <[email protected]>
Signed-off-by Eric Biggers <[email protected]>

---

v2:
- Also fix s390_sha1_import() and sha512_import()
- Use 0 instead of false
- Improved commit message

 arch/s390/crypto/sha1_s390.c   | 2 ++
 arch/s390/crypto/sha512_s390.c | 3 +++
 2 files changed, 5 insertions(+)
arch/s390/crypto/sha1_s390.c +2 -0
index d229cbd2ba229..9b0d55be12394 100644
@@ -36,10 +36,11 @@ static int s390_sha1_init(struct shash_desc *desc)
 	sctx->state[2] = SHA1_H2;
 	sctx->state[3] = SHA1_H3;
 	sctx->state[4] = SHA1_H4;
 	sctx->count = 0;
 	sctx->func = CPACF_KIMD_SHA_1;
+	sctx->first_message_part = 0;
 
 	return 0;
 }
 
 static int s390_sha1_export(struct shash_desc *desc, void *out)

@@ -58,10 +59,11 @@ static int s390_sha1_import(struct shash_desc *desc, const void *in)
 	const struct sha1_state *ictx = in;
 
 	sctx->count = ictx->count;
 	memcpy(sctx->state, ictx->state, sizeof(ictx->state));
 	sctx->func = CPACF_KIMD_SHA_1;
+	sctx->first_message_part = 0;
 	return 0;
 }
 
 static struct shash_alg alg = {
 	.digestsize	=	SHA1_DIGEST_SIZE,
arch/s390/crypto/sha512_s390.c +3 -0
index 33711a29618c3..6cbbf5e8555f8 100644
@@ -30,10 +30,11 @@ static int sha512_init(struct shash_desc *desc)
 	ctx->sha512.state[6] = SHA512_H6;
 	ctx->sha512.state[7] = SHA512_H7;
 	ctx->count = 0;
 	ctx->sha512.count_hi = 0;
 	ctx->func = CPACF_KIMD_SHA_512;
+	ctx->first_message_part = 0;
 
 	return 0;
 }
 
 static int sha512_export(struct shash_desc *desc, void *out)

@@ -55,10 +56,11 @@ static int sha512_import(struct shash_desc *desc, const void *in)
 	sctx->count = ictx->count[0];
 	sctx->sha512.count_hi = ictx->count[1];
 
 	memcpy(sctx->state, ictx->state, sizeof(ictx->state));
 	sctx->func = CPACF_KIMD_SHA_512;
+	sctx->first_message_part = 0;
 	return 0;
 }
 
 static struct shash_alg sha512_alg = {
 	.digestsize	=	SHA512_DIGEST_SIZE,

@@ -95,10 +97,11 @@ static int sha384_init(struct shash_desc *desc)
 	ctx->sha512.state[6] = SHA384_H6;
 	ctx->sha512.state[7] = SHA384_H7;
 	ctx->count = 0;
 	ctx->sha512.count_hi = 0;
 	ctx->func = CPACF_KIMD_SHA_512;
+	ctx->first_message_part = 0;
 
 	return 0;
 }
 
 static struct shash_alg sha384_alg = {

base-commit: 64f7548aad63d2fbca2eeb6eb33361c218ebd5a5

Signature · 1 line
2.50.0