[PATCH 3/6] apparmor: use SHASH_DESC_ON_STACK

From: John Johansen
Date: Thu Apr 06 2017 - 09:56:07 EST


From: Nicolas Iooss <nicolas.iooss_linux@xxxxxxx>

When building the kernel with clang, the compiler fails to build
security/apparmor/crypto.c with the following error:

security/apparmor/crypto.c:36:8: error: fields must have a constant
size: 'variable length array in structure' extension will never be
supported
char ctx[crypto_shash_descsize(apparmor_tfm)];
^

Since commit a0a77af14117 ("crypto: LLVMLinux: Add macro to remove use
of VLAIS in crypto code"), include/crypto/hash.h defines
SHASH_DESC_ON_STACK to work around this issue. Use it in aa_calc_hash()
and aa_calc_profile_hash().

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@xxxxxxx>
Signed-off-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
---
security/apparmor/crypto.c | 32 +++++++++++++-------------------
1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/security/apparmor/crypto.c b/security/apparmor/crypto.c
index de8dc78..136f2a0 100644
--- a/security/apparmor/crypto.c
+++ b/security/apparmor/crypto.c
@@ -31,10 +31,7 @@ unsigned int aa_hash_size(void)

char *aa_calc_hash(void *data, size_t len)
{
- struct {
- struct shash_desc shash;
- char ctx[crypto_shash_descsize(apparmor_tfm)];
- } desc;
+ SHASH_DESC_ON_STACK(desc, apparmor_tfm);
char *hash = NULL;
int error = -ENOMEM;

@@ -45,16 +42,16 @@ char *aa_calc_hash(void *data, size_t len)
if (!hash)
goto fail;

- desc.shash.tfm = apparmor_tfm;
- desc.shash.flags = 0;
+ desc->tfm = apparmor_tfm;
+ desc->flags = 0;

- error = crypto_shash_init(&desc.shash);
+ error = crypto_shash_init(desc);
if (error)
goto fail;
- error = crypto_shash_update(&desc.shash, (u8 *) data, len);
+ error = crypto_shash_update(desc, (u8 *) data, len);
if (error)
goto fail;
- error = crypto_shash_final(&desc.shash, hash);
+ error = crypto_shash_final(desc, hash);
if (error)
goto fail;

@@ -69,10 +66,7 @@ char *aa_calc_hash(void *data, size_t len)
int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
size_t len)
{
- struct {
- struct shash_desc shash;
- char ctx[crypto_shash_descsize(apparmor_tfm)];
- } desc;
+ SHASH_DESC_ON_STACK(desc, apparmor_tfm);
int error = -ENOMEM;
__le32 le32_version = cpu_to_le32(version);

@@ -86,19 +80,19 @@ int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
if (!profile->hash)
goto fail;

- desc.shash.tfm = apparmor_tfm;
- desc.shash.flags = 0;
+ desc->tfm = apparmor_tfm;
+ desc->flags = 0;

- error = crypto_shash_init(&desc.shash);
+ error = crypto_shash_init(desc);
if (error)
goto fail;
- error = crypto_shash_update(&desc.shash, (u8 *) &le32_version, 4);
+ error = crypto_shash_update(desc, (u8 *) &le32_version, 4);
if (error)
goto fail;
- error = crypto_shash_update(&desc.shash, (u8 *) start, len);
+ error = crypto_shash_update(desc, (u8 *) start, len);
if (error)
goto fail;
- error = crypto_shash_final(&desc.shash, profile->hash);
+ error = crypto_shash_final(desc, profile->hash);
if (error)
goto fail;

--
2.9.3