diff options
author | Casey Schaufler <casey@schaufler-ca.com> | 2013-10-12 01:06:39 (GMT) |
---|---|---|
committer | Casey Schaufler <casey@schaufler-ca.com> | 2013-10-18 16:39:33 (GMT) |
commit | c0ab6e56dcb7ca9903d460247cb464e769ae6e77 (patch) | |
tree | 52da39cb2798c0a4276d0d23fa3b4f1dbcd732f2 /security/smack/smack_lsm.c | |
parent | 5a5f2acfd04269e2e0958067216b68ff461c285c (diff) | |
download | linux-c0ab6e56dcb7ca9903d460247cb464e769ae6e77.tar.xz |
Smack: Implement lock security mode
Linux file locking does not follow the same rules
as other mechanisms. Even though it is a write operation
a process can set a read lock on files which it has open
only for read access. Two programs with read access to
a file can use read locks to communicate.
This is not acceptable in a Mandatory Access Control
environment. Smack treats setting a read lock as the
write operation that it is. Unfortunately, many programs
assume that setting a read lock is a read operation.
These programs are unhappy in the Smack environment.
This patch introduces a new access mode (lock) to address
this problem. A process with lock access to a file can
set a read lock. A process with write access to a file can
set a read lock or a write lock. This prevents a situation
where processes are granted write access just so they can
set read locks.
Targeted for git://git.gitorious.org/smack-next/kernel.git
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Diffstat (limited to 'security/smack/smack_lsm.c')
-rw-r--r-- | security/smack/smack_lsm.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 8825375..88d366e5 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1146,7 +1146,7 @@ static int smack_file_ioctl(struct file *file, unsigned int cmd, * @file: the object * @cmd: unused * - * Returns 0 if current has write access, error code otherwise + * Returns 0 if current has lock access, error code otherwise */ static int smack_file_lock(struct file *file, unsigned int cmd) { @@ -1154,7 +1154,7 @@ static int smack_file_lock(struct file *file, unsigned int cmd) smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); smk_ad_setfield_u_fs_path(&ad, file->f_path); - return smk_curacc(file->f_security, MAY_WRITE, &ad); + return smk_curacc(file->f_security, MAY_LOCK, &ad); } /** @@ -1178,8 +1178,13 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd, switch (cmd) { case F_GETLK: + break; case F_SETLK: case F_SETLKW: + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); + smk_ad_setfield_u_fs_path(&ad, file->f_path); + rc = smk_curacc(file->f_security, MAY_LOCK, &ad); + break; case F_SETOWN: case F_SETSIG: smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); |