Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

ima: Fix ima digest hash table key calculation

Browse source 
commit 1129d31b55d509f15e72dc68e4b5c3a4d7b4da8d upstream.

Function hash_long() accepts unsigned long, while currently only one byte
is passed from ima_hash_key(), which calculates a key for ima_htable.

Given that hashing the digest does not give clear benefits compared to
using the digest itself, remove hash_long() and return the modulus
calculated on the first two bytes of the digest with the number of slots.
Also reduce the depth of the hash table by doubling the number of slots.

Cc: stable@vger.kernel.org
Fixes: 3323eec921 ("integrity: IMA as an integrity service provider")
Co-developed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Krzysztof Struczynski <krzysztof.struczynski@huawei.com>
Acked-by: David.Laight@aculab.com (big endian system concerns)
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Krzysztof Struczynski 2020-04-28 09:30:10 +02:00 committed by Greg Kroah-Hartman
parent 88afa532c1
commit 71381daffe
1 changed files with 4 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
security/integrity/ima/ima.h
View file

@ -40,7 +40,7 @@ enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
#define IMA_DIGEST_SIZE SHA1_DIGEST_SIZE
#define IMA_EVENT_NAME_LEN_MAX 255
#define IMA_HASH_BITS 9
#define IMA_HASH_BITS 10
#define IMA_MEASURE_HTABLE_SIZE (1 << IMA_HASH_BITS)
#define IMA_TEMPLATE_FIELD_ID_MAX_LEN 16
@ -166,9 +166,10 @@ struct ima_h_table {
};
extern struct ima_h_table ima_htable;
static inline unsigned long ima_hash_key(u8 *digest)
static inline unsigned int ima_hash_key(u8 *digest)
{
return hash_long(*digest, IMA_HASH_BITS);
/* there is no point in taking a hash of part of a digest */
return (digest[0] | digest[1] << 8) % IMA_MEASURE_HTABLE_SIZE;
}
#define __ima_hooks(hook) \