[v3,11/12] security, crypto: LLVMLinux: Remove VLAIS from ima_crypto.c

Commit Message

Behan Webster Sept. 15, 2014, 7:30 a.m. UTC

From: Behan Webster <[e-mail]>

Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
compliant equivalent. This patch allocates the appropriate amount of memory
using a char array using the SHASH_DESC_ON_STACK macro.

The new code can be compiled with both gcc and clang.

Signed-off-by: Behan Webster <[e-mail]>
Reviewed-by: Mark Charlebois <[e-mail]>
Reviewed-by: Jan-Simon Möller <[e-mail]>
Cc: [e-mail]
---
 security/integrity/ima/ima_crypto.c | 51 +++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 28 deletions(-)

Comments

Linus Torvalds Sept. 15, 2014, 2:21 p.m. UTC | #1

On Mon, Sep 15, 2014 at 12:30 AM,  <[e-mail]> wrote:
> From: Behan Webster <[e-mail]>
>
> Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
> compliant equivalent. This patch allocates the appropriate amount of memory
> using a char array using the SHASH_DESC_ON_STACK macro.

You only made the first case use SHASH_DESC_ON_STACK, the two other
cases you left in the ugly format. Was that just an oversight, or was
there some reason for it?

             Linus
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Behan Webster Sept. 15, 2014, 2:25 p.m. UTC | #2

On 09/15/14 07:21, Linus Torvalds wrote:
> On Mon, Sep 15, 2014 at 12:30 AM,  <[e-mail]> wrote:
>> From: Behan Webster <[e-mail]>
>>
>> Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99
>> compliant equivalent. This patch allocates the appropriate amount of memory
>> using a char array using the SHASH_DESC_ON_STACK macro.
> You only made the first case use SHASH_DESC_ON_STACK, the two other
> cases you left in the ugly format. Was that just an oversight, or was
> there some reason for it?
>
Oversight. Will Fix.

Behan

Patch

diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 0bd7328..bb55737 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -380,17 +380,14 @@  static int ima_calc_file_hash_tfm(struct file *file,
 	loff_t i_size, offset = 0;
 	char *rbuf;
 	int rc, read = 0;
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(tfm)];
-	} desc;
+	SHASH_DESC_ON_STACK(shash, tfm);
 
-	desc.shash.tfm = tfm;
-	desc.shash.flags = 0;
+	shash->tfm = tfm;
+	shash->flags = 0;
 
 	hash->length = crypto_shash_digestsize(tfm);
 
-	rc = crypto_shash_init(&desc.shash);
+	rc = crypto_shash_init(shash);
 	if (rc != 0)
 		return rc;
 
@@ -420,7 +417,7 @@  static int ima_calc_file_hash_tfm(struct file *file,
 			break;
 		offset += rbuf_len;
 
-		rc = crypto_shash_update(&desc.shash, rbuf, rbuf_len);
+		rc = crypto_shash_update(shash, rbuf, rbuf_len);
 		if (rc)
 			break;
 	}
@@ -429,7 +426,7 @@  static int ima_calc_file_hash_tfm(struct file *file,
 	kfree(rbuf);
 out:
 	if (!rc)
-		rc = crypto_shash_final(&desc.shash, hash->digest);
+		rc = crypto_shash_final(shash, hash->digest);
 	return rc;
 }
 
@@ -487,18 +484,17 @@  static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
 					 struct ima_digest_data *hash,
 					 struct crypto_shash *tfm)
 {
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(tfm)];
-	} desc;
+	char desc[sizeof(struct shash_desc) +
+		crypto_shash_descsize(tfm)] CRYPTO_MINALIGN_ATTR;
+	struct shash_desc *shash = (struct shash_desc *)desc;
 	int rc, i;
 
-	desc.shash.tfm = tfm;
-	desc.shash.flags = 0;
+	shash->tfm = tfm;
+	shash->flags = 0;
 
 	hash->length = crypto_shash_digestsize(tfm);
 
-	rc = crypto_shash_init(&desc.shash);
+	rc = crypto_shash_init(shash);
 	if (rc != 0)
 		return rc;
 
@@ -508,7 +504,7 @@  static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
 		u32 datalen = field_data[i].len;
 
 		if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
-			rc = crypto_shash_update(&desc.shash,
+			rc = crypto_shash_update(shash,
 						(const u8 *) &field_data[i].len,
 						sizeof(field_data[i].len));
 			if (rc)
@@ -518,13 +514,13 @@  static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
 			data_to_hash = buffer;
 			datalen = IMA_EVENT_NAME_LEN_MAX + 1;
 		}
-		rc = crypto_shash_update(&desc.shash, data_to_hash, datalen);
+		rc = crypto_shash_update(shash, data_to_hash, datalen);
 		if (rc)
 			break;
 	}
 
 	if (!rc)
-		rc = crypto_shash_final(&desc.shash, hash->digest);
+		rc = crypto_shash_final(shash, hash->digest);
 
 	return rc;
 }
@@ -565,15 +561,14 @@  static int __init ima_calc_boot_aggregate_tfm(char *digest,
 {
 	u8 pcr_i[TPM_DIGEST_SIZE];
 	int rc, i;
-	struct {
-		struct shash_desc shash;
-		char ctx[crypto_shash_descsize(tfm)];
-	} desc;
+	char desc[sizeof(struct shash_desc) +
+		crypto_shash_descsize(tfm)] CRYPTO_MINALIGN_ATTR;
+	struct shash_desc *shash = (struct shash_desc *)desc;
 
-	desc.shash.tfm = tfm;
-	desc.shash.flags = 0;
+	shash->tfm = tfm;
+	shash->flags = 0;
 
-	rc = crypto_shash_init(&desc.shash);
+	rc = crypto_shash_init(shash);
 	if (rc != 0)
 		return rc;
 
@@ -581,10 +576,10 @@  static int __init ima_calc_boot_aggregate_tfm(char *digest,
 	for (i = TPM_PCR0; i < TPM_PCR8; i++) {
 		ima_pcrread(i, pcr_i);
 		/* now accumulate with current aggregate */
-		rc = crypto_shash_update(&desc.shash, pcr_i, TPM_DIGEST_SIZE);
+		rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE);
 	}
 	if (!rc)
-		crypto_shash_final(&desc.shash, digest);
+		crypto_shash_final(shash, digest);
 	return rc;
 }