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authorTyler Hicks <tyhicks@canonical.com>2013-09-29 08:39:21 -0700
committerJames Morris <james.l.morris@oracle.com>2013-09-30 09:53:59 +1000
commit71ac7f6255c560716c20da8ee2c964bbd96e941f (patch)
tree1826844de4bbe7ca69b79ad17adabf1ec52763d9 /security
parent15c03dd4859ab16f9212238f29dd315654aa94f6 (diff)
downloadlinux-71ac7f6255c560716c20da8ee2c964bbd96e941f.tar.gz
apparmor: Use shash crypto API interface for profile hashes
Use the shash interface, rather than the hash interface, when hashing AppArmor profiles. The shash interface does not use scatterlists and it is a better fit for what AppArmor needs. This fixes a kernel paging BUG when aa_calc_profile_hash() is passed a buffer from vmalloc(). The hash interface requires callers to handle vmalloc() buffers differently than what AppArmor was doing. Due to vmalloc() memory not being physically contiguous, each individual page behind the buffer must be assigned to a scatterlist with sg_set_page() and then the scatterlist passed to crypto_hash_update(). The shash interface does not have that limitation and allows vmalloc() and kmalloc() buffers to be handled in the same manner. BugLink: https://launchpad.net/bugs/1216294/ BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=62261 Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Acked-by: Seth Arnold <seth.arnold@canonical.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: James Morris <james.l.morris@oracle.com>
Diffstat (limited to 'security')
-rw-r--r--security/apparmor/crypto.c34
1 files changed, 16 insertions, 18 deletions
diff --git a/security/apparmor/crypto.c b/security/apparmor/crypto.c
index d6222ba4e91..532471d0b3a 100644
--- a/security/apparmor/crypto.c
+++ b/security/apparmor/crypto.c
@@ -15,14 +15,14 @@
* it should be.
*/
-#include <linux/crypto.h>
+#include <crypto/hash.h>
#include "include/apparmor.h"
#include "include/crypto.h"
static unsigned int apparmor_hash_size;
-static struct crypto_hash *apparmor_tfm;
+static struct crypto_shash *apparmor_tfm;
unsigned int aa_hash_size(void)
{
@@ -32,35 +32,33 @@ unsigned int aa_hash_size(void)
int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
size_t len)
{
- struct scatterlist sg[2];
- struct hash_desc desc = {
- .tfm = apparmor_tfm,
- .flags = 0
- };
+ struct {
+ struct shash_desc shash;
+ char ctx[crypto_shash_descsize(apparmor_tfm)];
+ } desc;
int error = -ENOMEM;
u32 le32_version = cpu_to_le32(version);
if (!apparmor_tfm)
return 0;
- sg_init_table(sg, 2);
- sg_set_buf(&sg[0], &le32_version, 4);
- sg_set_buf(&sg[1], (u8 *) start, len);
-
profile->hash = kzalloc(apparmor_hash_size, GFP_KERNEL);
if (!profile->hash)
goto fail;
- error = crypto_hash_init(&desc);
+ desc.shash.tfm = apparmor_tfm;
+ desc.shash.flags = 0;
+
+ error = crypto_shash_init(&desc.shash);
if (error)
goto fail;
- error = crypto_hash_update(&desc, &sg[0], 4);
+ error = crypto_shash_update(&desc.shash, (u8 *) &le32_version, 4);
if (error)
goto fail;
- error = crypto_hash_update(&desc, &sg[1], len);
+ error = crypto_shash_update(&desc.shash, (u8 *) start, len);
if (error)
goto fail;
- error = crypto_hash_final(&desc, profile->hash);
+ error = crypto_shash_final(&desc.shash, profile->hash);
if (error)
goto fail;
@@ -75,19 +73,19 @@ fail:
static int __init init_profile_hash(void)
{
- struct crypto_hash *tfm;
+ struct crypto_shash *tfm;
if (!apparmor_initialized)
return 0;
- tfm = crypto_alloc_hash("sha1", 0, CRYPTO_ALG_ASYNC);
+ tfm = crypto_alloc_shash("sha1", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm)) {
int error = PTR_ERR(tfm);
AA_ERROR("failed to setup profile sha1 hashing: %d\n", error);
return error;
}
apparmor_tfm = tfm;
- apparmor_hash_size = crypto_hash_digestsize(apparmor_tfm);
+ apparmor_hash_size = crypto_shash_digestsize(apparmor_tfm);
aa_info_message("AppArmor sha1 policy hashing enabled");