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authorCasey Schaufler <casey@schaufler-ca.com>2014-04-21 11:10:26 -0700
committerCasey Schaufler <casey@schaufler-ca.com>2014-04-23 08:52:39 -0700
commita6834c0b9114c06106efee8e9f2a11fbbb104567 (patch)
tree61086ddbe2c1e5fbb7d9d487f801f6c0623901b7 /security/smack
parent54e70ec5eb090193b03e69d551fa6771a5a217c4 (diff)
downloadlinux-stericsson-a6834c0b9114c06106efee8e9f2a11fbbb104567.tar.gz
Smack: Verify read access on file open - v3
Smack believes that many of the operatons that can be performed on an open file descriptor are read operations. The fstat and lseek system calls are examples. An implication of this is that files shouldn't be open if the task doesn't have read access even if it has write access and the file is being opened write only. Targeted for git://git.gitorious.org/smack-next/kernel.git Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Diffstat (limited to 'security/smack')
-rw-r--r--security/smack/smack_lsm.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 3410e3abd19b..7bcf9edf768d 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1462,19 +1462,32 @@ static int smack_file_receive(struct file *file)
/**
* smack_file_open - Smack dentry open processing
* @file: the object
- * @cred: unused
+ * @cred: task credential
*
* Set the security blob in the file structure.
+ * Allow the open only if the task has read access. There are
+ * many read operations (e.g. fstat) that you can do with an
+ * fd even if you have the file open write-only.
*
* Returns 0
*/
static int smack_file_open(struct file *file, const struct cred *cred)
{
+ struct task_smack *tsp = cred->security;
struct inode_smack *isp = file_inode(file)->i_security;
+ struct smk_audit_info ad;
+ int rc;
- file->f_security = isp->smk_inode;
+ if (smack_privileged(CAP_MAC_OVERRIDE))
+ return 0;
- return 0;
+ smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+ smk_ad_setfield_u_fs_path(&ad, file->f_path);
+ rc = smk_access(tsp->smk_task, isp->smk_inode, MAY_READ, &ad);
+ if (rc == 0)
+ file->f_security = isp->smk_inode;
+
+ return rc;
}
/*