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integrity: add ima_counts_put (updated) 

This patch fixes an imbalance message as reported by J.R. Okajima.
The IMA file counters are incremented in ima_path_check. If the
actual open fails, such as ETXTBSY, decrement the counters to
prevent unnecessary imbalance messages.

Reported-by: J.R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Mimi Zohar 2009-06-26 14:05:27 -04:00 committed by James Morris
parent 79b854c549
commit 94e5d714f6
3 changed files with 41 additions and 1 deletions
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7
fs/namei.c
View File

@ -1761,6 +1761,10 @@ struct file *do_filp_open(int dfd, const char *pathname,
goto exit;
}
filp = nameidata_to_filp(&nd, open_flag);
if (IS_ERR(filp))
ima_counts_put(&nd.path,
acc_mode & (MAY_READ | MAY_WRITE |
MAY_EXEC));
mnt_drop_write(nd.path.mnt);
if (nd.root.mnt)
path_put(&nd.root);
@ -1817,6 +1821,9 @@ struct file *do_filp_open(int dfd, const char *pathname,
goto exit;
}
filp = nameidata_to_filp(&nd, open_flag);
if (IS_ERR(filp))
ima_counts_put(&nd.path,
acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC));
/*
* It is now safe to drop the mnt write
* because the filp has had a write taken

6
include/linux/ima.h
View File

@ -24,6 +24,7 @@ extern int ima_path_check(struct path *path, int mask, int update_counts);
extern void ima_file_free(struct file *file);
extern int ima_file_mmap(struct file *file, unsigned long prot);
extern void ima_counts_get(struct file *file);
extern void ima_counts_put(struct path *path, int mask);
#else
static inline int ima_bprm_check(struct linux_binprm *bprm)
@ -60,5 +61,10 @@ static inline void ima_counts_get(struct file *file)
{
return;
}
static inline void ima_counts_put(struct path *path, int mask)
{
return;
}
#endif /* CONFIG_IMA_H */
#endif /* _LINUX_IMA_H */

29
security/integrity/ima/ima_main.c
View File

@ -238,7 +238,34 @@ static int process_measurement(struct file *file, const unsigned char *filename,
}
/*
* ima_opens_get - increment file counts
* ima_counts_put - decrement file counts
*
* File counts are incremented in ima_path_check. On file open
* error, such as ETXTBSY, decrement the counts to prevent
* unnecessary imbalance messages.
*/
void ima_counts_put(struct path *path, int mask)
{
struct inode *inode = path->dentry->d_inode;
struct ima_iint_cache *iint;
if (!ima_initialized || !S_ISREG(inode->i_mode))
return;
iint = ima_iint_find_insert_get(inode);
if (!iint)
return;
mutex_lock(&iint->mutex);
iint->opencount--;
if ((mask & MAY_WRITE) || (mask == 0))
iint->writecount--;
else if (mask & (MAY_READ | MAY_EXEC))
iint->readcount--;
mutex_unlock(&iint->mutex);
}
/*
* ima_counts_get - increment file counts
*
* - for IPC shm and shmat file.
* - for nfsd exported files.