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

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Commit 88c02b3f79 ("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/73477fe9-a1dc-4e38-98a6-eba9921e8afa@linux.ibm.com/).
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: 88c02b3f79 ("s390/sha3: Support sha3 performance enhancements")
Cc: stable@vger.kernel.org
Reported-by: Ingo Franzki <ifranzki@linux.ibm.com>
Closes: https://lore.kernel.org/r/12740696-595c-4604-873e-aefe8b405fbf@linux.ibm.com
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20250703172316.7914-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
This commit is contained in:
Eric Biggers 2025-07-03 10:23:16 -07:00
parent 64f7548aad
commit 6827938026
2 changed files with 5 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/s390/crypto/sha1_s390.c
View File

@ -38,6 +38,7 @@ static int s390_sha1_init(struct shash_desc *desc)
sctx->state[4] = SHA1_H4;
sctx->count = 0;
sctx->func = CPACF_KIMD_SHA_1;
sctx->first_message_part = 0;
return 0;
}
@ -60,6 +61,7 @@ static int s390_sha1_import(struct shash_desc *desc, const void *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;
}

3
arch/s390/crypto/sha512_s390.c
View File

@ -32,6 +32,7 @@ static int sha512_init(struct shash_desc *desc)
ctx->count = 0;
ctx->sha512.count_hi = 0;
ctx->func = CPACF_KIMD_SHA_512;
ctx->first_message_part = 0;
return 0;
}
@ -57,6 +58,7 @@ static int sha512_import(struct shash_desc *desc, const void *in)
memcpy(sctx->state, ictx->state, sizeof(ictx->state));
sctx->func = CPACF_KIMD_SHA_512;
sctx->first_message_part = 0;
return 0;
}
@ -97,6 +99,7 @@ static int sha384_init(struct shash_desc *desc)
ctx->count = 0;
ctx->sha512.count_hi = 0;
ctx->func = CPACF_KIMD_SHA_512;
ctx->first_message_part = 0;
return 0;
}