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crypto: caam - guard HMAC key hex dumps in hash_digest_key

PATCH In review Thorsten Blum 2 participants 2 messages Mar 18 – Mar 19

Subsystems (3)
Stable branch Crypto API Freescale CAAM (Cryptographic Acceleration and Assurance Module) driver
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Thorsten Blum

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#0 lore raw

PATCH v2 1/1 crypto: caam - guard HMAC key hex dumps in hash_digest_key

Guard sensitive HMAC key hex dumps with DEBUG in hash_digest_key() to avoid leaking secrets at runtime when CONFIG_DYNAMIC_DEBUG is enabled.

Fixes 045e36780f11 ("crypto: caam - ahash hmac support")
Fixes 3f16f6c9d632 ("crypto: caam/qi2 - add support for ahash algorithms")
Cc [email protected]
Signed-off-by Thorsten Blum <[email protected]>

---
Changes in v2:
- Debug-guard key hex dumps instead of removing them entirely (Herbert)
- Use print_hex_dump() instead of print_hex_dump_debug() since the dumps
are already guarded by DEBUG
- Link to v1: https://lore.kernel.org/lkml/[email protected]/

---
 drivers/crypto/caam/caamalg_qi2.c | 13 ++++++++-----
 drivers/crypto/caam/caamhash.c    | 13 ++++++++-----
 2 files changed, 16 insertions(+), 10 deletions(-)
drivers/crypto/caam/caamalg_qi2.c +8 -5
index 167372936ca7..3392070942ab 100644
@@ -3269,8 +3269,10 @@ static int hash_digest_key(struct caam_hash_ctx *ctx, u32 *keylen, u8 *key,
 	dpaa2_fl_set_addr(out_fle, key_dma);
 	dpaa2_fl_set_len(out_fle, digestsize);
 
-	print_hex_dump_debug("key_in@" __stringify(__LINE__)": ",
-			     DUMP_PREFIX_ADDRESS, 16, 4, key, *keylen, 1);
+#ifdef DEBUG
+	print_hex_dump(KERN_DEBUG, "key_in@" __stringify(__LINE__)": ",
+		       DUMP_PREFIX_ADDRESS, 16, 4, key, *keylen, 1);
+#endif
 	print_hex_dump_debug("shdesc@" __stringify(__LINE__)": ",
 			     DUMP_PREFIX_ADDRESS, 16, 4, desc, desc_bytes(desc),
 			     1);

@@ -3289,9 +3291,10 @@ static int hash_digest_key(struct caam_hash_ctx *ctx, u32 *keylen, u8 *key,
 		/* in progress */
 		wait_for_completion(&result.completion);
 		ret = result.err;
-		print_hex_dump_debug("digested key@" __stringify(__LINE__)": ",
-				     DUMP_PREFIX_ADDRESS, 16, 4, key,
-				     digestsize, 1);
+#ifdef DEBUG
+		print_hex_dump(KERN_DEBUG, "digested key@" __stringify(__LINE__)": ",
+			       DUMP_PREFIX_ADDRESS, 16, 4, key, digestsize, 1);
+#endif
 	}
 
 	dma_unmap_single(ctx->dev, flc_dma, sizeof(flc->flc) + desc_bytes(desc),
drivers/crypto/caam/caamhash.c +8 -5
index 628c43a7efc4..0dad6fb6caeb 100644
@@ -393,8 +393,10 @@ static int hash_digest_key(struct caam_hash_ctx *ctx, u32 *keylen, u8 *key,
 	append_seq_store(desc, digestsize, LDST_CLASS_2_CCB |
 			 LDST_SRCDST_BYTE_CONTEXT);
 
-	print_hex_dump_debug("key_in@"__stringify(__LINE__)": ",
-			     DUMP_PREFIX_ADDRESS, 16, 4, key, *keylen, 1);
+#ifdef DEBUG
+	print_hex_dump(KERN_DEBUG, "key_in@"__stringify(__LINE__)": ",
+		       DUMP_PREFIX_ADDRESS, 16, 4, key, *keylen, 1);
+#endif
 	print_hex_dump_debug("jobdesc@"__stringify(__LINE__)": ",
 			     DUMP_PREFIX_ADDRESS, 16, 4, desc, desc_bytes(desc),
 			     1);

@@ -408,9 +410,10 @@ static int hash_digest_key(struct caam_hash_ctx *ctx, u32 *keylen, u8 *key,
 		wait_for_completion(&result.completion);
 		ret = result.err;
 
-		print_hex_dump_debug("digested key@"__stringify(__LINE__)": ",
-				     DUMP_PREFIX_ADDRESS, 16, 4, key,
-				     digestsize, 1);
+#ifdef DEBUG
+		print_hex_dump(KERN_DEBUG, "digested key@"__stringify(__LINE__)": ",
+			       DUMP_PREFIX_ADDRESS, 16, 4, key, digestsize, 1);
+#endif
 	}
 	dma_unmap_single(jrdev, key_dma, *keylen, DMA_BIDIRECTIONAL);
maintainer
#1 lore raw
Quoted 6 lines · Thorsten Blum
drivers/crypto/caam/caamalg_qi2.c +0 -0
index 167372936ca7..3392070942ab 100644

drivers/crypto/caam/caamalg_qi2.c static int hash_digest_key(struct caam_hash_ctx *ctx, u32 *keylen, u8 *key, · line 3275

Quoted 9 lines
drivers/crypto/caam/caamalg_qi2.c +4 -2
@@ -3269,8 +3269,10 @@ static int hash_digest_key(struct caam_hash_ctx *ctx, u32 *keylen, u8 *key,
 	dpaa2_fl_set_addr(out_fle, key_dma);
 	dpaa2_fl_set_len(out_fle, digestsize);
 
-	print_hex_dump_debug("key_in@" __stringify(__LINE__)": ",
-			     DUMP_PREFIX_ADDRESS, 16, 4, key, *keylen, 1);
+#ifdef DEBUG
+	print_hex_dump(KERN_DEBUG, "key_in@" __stringify(__LINE__)": ",
+		       DUMP_PREFIX_ADDRESS, 16, 4, key, *keylen, 1);
+#endif

I'd prefer to keep the compiler coverage when DEBUG is off.

Please add a new helper, either print_hex_dump_devel or print_hex_dump_sensitive that only gets enabled when DEBUG is defined.

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