The new LSM hook security_file_getsecid() and its implementation in the
capability module, SELinux and SMACK allows to obtain the security
identifier associated to a file descriptor.
Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxx>
---
include/linux/security.h | 12 ++++++++++++
security/capability.c | 6 ++++++
security/security.c | 6 ++++++
security/selinux/hooks.c | 7 +++++++
security/smack/smack_lsm.c | 11 +++++++++++
5 files changed, 42 insertions(+), 0 deletions(-)
diff --git a/include/linux/security.h b/include/linux/security.h
index ca02f17..6e73a1a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -630,6 +630,11 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
* to receive an open file descriptor via socket IPC.
* @file contains the file structure being received.
* Return 0 if permission is granted.
+ * @file_getsecid:
+ * Get the secid associated with the file descriptor.
+ * @file contains a pointer to the file descriptor.
+ * @secid contains a pointer to the location where result will be saved.
+ * In case of failure, @secid will be set to zero.
*
* Security hook for dentry
*
@@ -1492,6 +1497,7 @@ struct security_operations {
int (*file_send_sigiotask) (struct task_struct *tsk,
struct fown_struct *fown, int sig);
int (*file_receive) (struct file *file);
+ void (*file_getsecid)(const struct file *file, u32 *secid);
int (*dentry_open) (struct file *file, const struct cred *cred);
int (*task_create) (unsigned long clone_flags);
@@ -1751,6 +1757,7 @@ int security_file_set_fowner(struct file *file);
int security_file_send_sigiotask(struct task_struct *tsk,
struct fown_struct *fown, int sig);
int security_file_receive(struct file *file);
+void security_file_getsecid(const struct file *file, u32 *secid);
int security_dentry_open(struct file *file, const struct cred *cred);
int security_task_create(unsigned long clone_flags);
int security_cred_alloc_blank(struct cred *cred, gfp_t gfp);
@@ -2251,6 +2258,11 @@ static inline int security_file_receive(struct file *file)
return 0;
}
+static inline void security_file_getsecid(const struct file *file, u32 *secid)
+{
+ *secid = 0;
+}
+
static inline int security_dentry_open(struct file *file,
const struct cred *cred)
{
diff --git a/security/capability.c b/security/capability.c
index 2984ea4..fcb569d 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -349,6 +349,11 @@ static int cap_file_receive(struct file *file)
return 0;
}
+static void cap_file_getsecid(const struct file *file, u32 *secid)
+{
+ *secid = 0;
+}
+
static int cap_dentry_open(struct file *file, const struct cred *cred)
{
return 0;
@@ -953,6 +958,7 @@ void __init security_fixup_ops(struct security_operations *ops)
set_to_cap_if_null(ops, file_set_fowner);
set_to_cap_if_null(ops, file_send_sigiotask);
set_to_cap_if_null(ops, file_receive);
+ set_to_cap_if_null(ops, file_getsecid);
set_to_cap_if_null(ops, dentry_open);
set_to_cap_if_null(ops, task_create);
set_to_cap_if_null(ops, cred_alloc_blank);
diff --git a/security/security.c b/security/security.c
index 1011423..9973dab 100644
--- a/security/security.c
+++ b/security/security.c
@@ -688,6 +688,12 @@ int security_file_receive(struct file *file)
return security_ops->file_receive(file);
}
+void security_file_getsecid(const struct file *file, u32 *secid)
+{
+ security_ops->file_getsecid(file, secid);
+}
+EXPORT_SYMBOL(security_file_getsecid);
+
int security_dentry_open(struct file *file, const struct cred *cred)
{
int ret;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 6772687..e1e787c 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3179,6 +3179,12 @@ static int selinux_file_receive(struct file *file)
return file_has_perm(cred, file, file_to_av(file));
}
+static void selinux_file_getsecid(const struct file *file, u32 *secid)
+{
+ struct file_security_struct *fsec = file->f_security;
+ *secid = fsec->sid;
+}
+
static int selinux_dentry_open(struct file *file, const struct cred *cred)
{
struct file_security_struct *fsec;
@@ -5498,6 +5504,7 @@ static struct security_operations selinux_ops = {
.file_set_fowner = selinux_file_set_fowner,
.file_send_sigiotask = selinux_file_send_sigiotask,
.file_receive = selinux_file_receive,
+ .file_getsecid = selinux_file_getsecid,
.dentry_open = selinux_dentry_open,
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 6612ba1..a583736 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1304,6 +1304,16 @@ static int smack_file_receive(struct file *file)
return smk_curacc(file->f_security, may, &ad);
}
+/**
+ * smack_file_getsecid - Extract file descriptor's security id
+ * @file: file descriptor to extract the info from
+ * @secid: where result will be saved
+ */
+static void smack_file_getsecid(const struct file *file, u32 *secid)
+{
+ *secid = smack_to_secid(file->f_security);
+}
+
/*
* Task hooks
*/
@@ -3434,6 +3444,7 @@ struct security_operations smack_ops = {
.file_set_fowner = smack_file_set_fowner,
.file_send_sigiotask = smack_file_send_sigiotask,
.file_receive = smack_file_receive,
+ .file_getsecid = smack_file_getsecid,
.cred_alloc_blank = smack_cred_alloc_blank,
.cred_free = smack_cred_free,
--
1.7.4.4
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