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IMA: use unsigned int instead of long for counters 

Currently IMA uses 2 longs in struct inode.  To save space (and as it
seems impossible to overflow 32 bits) we switch these to unsigned int.
The switch to unsigned does require slightly different checks for
underflow, but it isn't complex.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Eric Paris 2010-10-25 14:41:32 -04:00 committed by Linus Torvalds
parent b575156daf
commit 497f323370
3 changed files with 14 additions and 9 deletions
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4
security/integrity/ima/ima.h
View File

@ -106,8 +106,8 @@ struct ima_iint_cache {
unsigned long flags;
u8 digest[IMA_DIGEST_SIZE];
struct mutex mutex; /* protects: version, flags, digest */
long readcount; /* measured files readcount */
long writecount; /* measured files writecount */
unsigned int readcount; /* measured files readcount */
unsigned int writecount;/* measured files writecount */
struct kref refcount; /* ima_iint_cache reference count */
};

4
security/integrity/ima/ima_iint.c
View File

@ -125,12 +125,12 @@ void iint_free(struct kref *kref)
iint->version = 0;
iint->flags = 0UL;
if (iint->readcount != 0) {
printk(KERN_INFO "%s: readcount: %ld\n", __func__,
printk(KERN_INFO "%s: readcount: %u\n", __func__,
iint->readcount);
iint->readcount = 0;
}
if (iint->writecount != 0) {
printk(KERN_INFO "%s: writecount: %ld\n", __func__,
printk(KERN_INFO "%s: writecount: %u\n", __func__,
iint->writecount);
iint->writecount = 0;
}

15
security/integrity/ima/ima_main.c
View File

@ -178,11 +178,18 @@ static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode,
struct file *file)
{
mode_t mode = file->f_mode;
bool dump = false;
BUG_ON(!mutex_is_locked(&iint->mutex));
if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
if (unlikely(iint->readcount == 0))
dump = true;
iint->readcount--;
}
if (mode & FMODE_WRITE) {
if (unlikely(iint->writecount == 0))
dump = true;
iint->writecount--;
if (iint->writecount == 0) {
if (iint->version != inode->i_version)
@ -190,10 +197,8 @@ static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode,
}
}
if (((iint->readcount < 0) ||
(iint->writecount < 0)) &&
!ima_limit_imbalance(file)) {
printk(KERN_INFO "%s: open/free imbalance (r:%ld w:%ld)\n",
if (dump && !ima_limit_imbalance(file)) {
printk(KERN_INFO "%s: open/free imbalance (r:%u w:%u)\n",
__func__, iint->readcount, iint->writecount);
dump_stack();
}