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crypto: testmgr - skip crc32c context test for ahash algorithms

PATCH In review Eric Biggers 2 participants 2 messages Jan 24, 2019 – Feb 1, 2019

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Crypto API Arm STM32
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Eric Biggers

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PATCH 1/1 crypto: testmgr - skip crc32c context test for ahash algorithms

From: Eric Biggers <[email protected]>

Instantiating "cryptd(crc32c)" causes a crypto self-test failure because the crypto_alloc_shash() in alg_test_crc32c() fails. This is because cryptd(crc32c) is an ahash algorithm, not a shash algorithm; so it can only be accessed through the ahash API, unlike shash algorithms which can be accessed through both the ahash and shash APIs.

As the test is testing the shash descriptor format which is only applicable to shash algorithms, skip it for ahash algorithms.

(Note that it's still important to fix crypto self-test failures even
for weird algorithm instantiations like cryptd(crc32c) that no one would really use; in fips_enabled mode unprivileged users can use them to panic the kernel, and also they prevent treating a crypto self-test failure as a bug when fuzzing the kernel.)

Fixes 8e3ee85e68c5 ("crypto: crc32c - Test descriptor context format")
Cc [email protected]
Signed-off-by Eric Biggers <[email protected]>
---
 crypto/testmgr.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)
crypto/testmgr.c +10 -4
index 8e36fa3605d73..45e1c3c61a19d 100644
@@ -2156,14 +2156,21 @@ static int alg_test_crc32c(const struct alg_test_desc *desc,
 
 	err = alg_test_hash(desc, driver, type, mask);
 	if (err)
-		goto out;
+		return err;
 
 	tfm = crypto_alloc_shash(driver, type, mask);
 	if (IS_ERR(tfm)) {
+		if (PTR_ERR(tfm) == -ENOENT) {
+			/*
+			 * This crc32c implementation is only available through
+			 * ahash API, not the shash API, so the remaining part
+			 * of the test is not applicable to it.
+			 */
+			return 0;
+		}
 		printk(KERN_ERR "alg: crc32c: Failed to load transform for %s: "
 		       "%ld\n", driver, PTR_ERR(tfm));
-		err = PTR_ERR(tfm);
-		goto out;
+		return PTR_ERR(tfm);
 	}
 
 	do {

@@ -2190,7 +2197,6 @@ static int alg_test_crc32c(const struct alg_test_desc *desc,
 
 	crypto_free_shash(tfm);
 
-out:
 	return err;
 }
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2.20.1
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Quoted 17 lines · Eric Biggers

From: Eric Biggers <[email protected]>

Instantiating "cryptd(crc32c)" causes a crypto self-test failure because the crypto_alloc_shash() in alg_test_crc32c() fails. This is because cryptd(crc32c) is an ahash algorithm, not a shash algorithm; so it can only be accessed through the ahash API, unlike shash algorithms which can be accessed through both the ahash and shash APIs.

As the test is testing the shash descriptor format which is only applicable to shash algorithms, skip it for ahash algorithms.

(Note that it's still important to fix crypto self-test failures even
for weird algorithm instantiations like cryptd(crc32c) that no one would really use; in fips_enabled mode unprivileged users can use them to panic the kernel, and also they prevent treating a crypto self-test failure as a bug when fuzzing the kernel.)

Quoted 6 lines
Fixes 8e3ee85e68c5 ("crypto: crc32c - Test descriptor context format")
Cc [email protected]
Signed-off-by Eric Biggers <[email protected]>
---
 crypto/testmgr.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

Patch applied. Thanks.

Signature · 3 lines
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt