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Date: Thu, 28 Oct 2010 18:02:03 -0400
From: Mimi Zohar <zohar@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: Mimi Zohar <zohar@...ux.vnet.ibm.com>,
linux-security-module@...r.kernel.org,
linux-fsdevel@...r.kernel.org, hch@...radead.org,
warthog9@...nel.org, david@...morbit.com, jmorris@...ei.org,
kyle@...artin.ca, hpa@...or.com, akpm@...ux-foundation.org,
torvalds@...ux-foundation.org, mingo@...e.hu, eparis@...hat.com,
viro@...iv.linux.org.uk, Matthew Wilcox <matthew@....cx>,
Mimi Zohar <zohar@...ibm.com>
Subject: [PATCH 2/4] IMA: maintain i_readcount in the VFS layer
ima_counts_get() updated the readcount and invalidated the PCR,
as necessary. Only update the i_readcount in the VFS layer.
Move the PCR invalidation checks to ima_file_check(), where it
belongs.
Maintaining the i_readcount in the VFS layer, will allow other
subsystems to use i_readcount.
Signed-off-by: Mimi Zohar <zohar@...ibm.com>
---
fs/file_table.c | 5 ++++-
fs/inode.c | 3 +++
fs/open.c | 3 ++-
include/linux/ima.h | 6 ------
security/integrity/ima/ima_iint.c | 2 --
security/integrity/ima/ima_main.c | 21 ++++++---------------
6 files changed, 15 insertions(+), 25 deletions(-)
diff --git a/fs/file_table.c b/fs/file_table.c
index a04bdd8..f7b7029 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -191,7 +191,8 @@ struct file *alloc_file(struct path *path, fmode_t mode,
file_take_write(file);
WARN_ON(mnt_clone_write(path->mnt));
}
- ima_counts_get(file);
+ if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
+ iget_readcount(path->dentry->d_inode);
return file;
}
EXPORT_SYMBOL(alloc_file);
@@ -252,6 +253,8 @@ static void __fput(struct file *file)
fops_put(file->f_op);
put_pid(file->f_owner.pid);
file_sb_list_del(file);
+ if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
+ iput_readcount(inode);
if (file->f_mode & FMODE_WRITE)
drop_file_write_access(file);
file->f_path.dentry = NULL;
diff --git a/fs/inode.c b/fs/inode.c
index 56d909d..1e806e0 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -139,6 +139,9 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
inode->i_nlink = 1;
inode->i_uid = 0;
inode->i_gid = 0;
+#ifdef CONFIG_IMA
+ inode->i_readcount = 0;
+#endif
atomic_set(&inode->i_writecount, 0);
inode->i_size = 0;
inode->i_blocks = 0;
diff --git a/fs/open.c b/fs/open.c
index d74e198..a6da4f7 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -688,7 +688,8 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
if (error)
goto cleanup_all;
}
- ima_counts_get(f);
+ if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
+ iget_readcount(inode);
f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 975837e..09e6e62 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -20,7 +20,6 @@ extern void ima_inode_free(struct inode *inode);
extern int ima_file_check(struct file *file, int mask);
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);
#else
static inline int ima_bprm_check(struct linux_binprm *bprm)
@@ -53,10 +52,5 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot)
return 0;
}
-static inline void ima_counts_get(struct file *file)
-{
- return;
-}
-
#endif /* CONFIG_IMA_H */
#endif /* _LINUX_IMA_H */
diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c
index c442e47..c4e381a 100644
--- a/security/integrity/ima/ima_iint.c
+++ b/security/integrity/ima/ima_iint.c
@@ -140,8 +140,6 @@ void ima_inode_free(struct inode *inode)
if (inode->i_readcount)
printk(KERN_INFO "%s: readcount: %u\n", __func__, inode->i_readcount);
- inode->i_readcount = 0;
-
if (!IS_IMA(inode))
return;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 203de97..ce2cd73 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -86,17 +86,16 @@ out:
}
/*
- * ima_counts_get - increment file counts
+ * ima_rdwr_violation_check
*
- * Maintain read/write counters for all files, but only
- * invalidate the PCR for measured files:
+ * Only invalidate the PCR for measured files:
* - Opening a file for write when already open for read,
* results in a time of measure, time of use (ToMToU) error.
* - Opening a file for read when already open for write,
* could result in a file measurement error.
*
*/
-void ima_counts_get(struct file *file)
+static void ima_rdwr_violation_check(struct file *file)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
@@ -104,14 +103,11 @@ void ima_counts_get(struct file *file)
int rc;
bool send_tomtou = false, send_writers = false;
- if (!S_ISREG(inode->i_mode))
+ if (!S_ISREG(inode->i_mode) || !ima_initialized)
return;
spin_lock(&inode->i_lock);
- if (!ima_initialized)
- goto out;
-
if (mode & FMODE_WRITE) {
if (inode->i_readcount && IS_IMA(inode))
send_tomtou = true;
@@ -125,10 +121,6 @@ void ima_counts_get(struct file *file)
if (atomic_read(&inode->i_writecount) > 0)
send_writers = true;
out:
- /* remember the vfs deals with i_writecount */
- if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
- inode->i_readcount++;
-
spin_unlock(&inode->i_lock);
if (send_tomtou)
@@ -157,7 +149,6 @@ static void ima_dec_counts(struct inode *inode, struct file *file)
}
return;
}
- inode->i_readcount--;
}
}
@@ -202,8 +193,7 @@ static void ima_file_free_noiint(struct inode *inode, struct file *file)
* ima_file_free - called on __fput()
* @file: pointer to file structure being freed
*
- * Flag files that changed, based on i_version;
- * and decrement the i_readcount.
+ * Flag files that changed, based on i_version
*/
void ima_file_free(struct file *file)
{
@@ -317,6 +307,7 @@ int ima_file_check(struct file *file, int mask)
{
int rc;
+ ima_rdwr_violation_check(file);
rc = process_measurement(file, file->f_dentry->d_name.name,
mask & (MAY_READ | MAY_WRITE | MAY_EXEC),
FILE_CHECK);
--
1.7.2.2
--
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