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Date:   Sat, 12 Aug 2023 20:31:08 +0500
From:   Khadija Kamran <kamrankhadijadj@gmail.com>
To:     Paul Moore <paul@paul-moore.com>, James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Stephen Smalley <stephen.smalley.work@gmail.com>,
        Eric Paris <eparis@parisplace.org>, selinux@vger.kernel.org,
        ztarkhani@microsoft.com,
        Alison Schofield <alison.schofield@intel.com>
Subject: [PATCH] lsm: constify the 'file' parameter in
 security_binder_transfer_file()
Message-ID: <ZNelvBCFG7wZt24g@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Precedence: bulk

SELinux registers the implementation for the "binder_transfer_file"
hook. Looking at the function implementation we observe that the
parameter "file" is not changing.

Mark the "file" parameter of LSM hook security_binder_transfer_file() as
"const" since it will not be changing in the LSM hook.

Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com>
---
 include/linux/lsm_hook_defs.h | 2 +-
 include/linux/security.h      | 4 ++--
 security/security.c           | 2 +-
 security/selinux/hooks.c      | 8 ++++----
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 6bb55e61e8e8..cda9e787cfc2 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -32,7 +32,7 @@ LSM_HOOK(int, 0, binder_transaction, const struct cred *from,
 LSM_HOOK(int, 0, binder_transfer_binder, const struct cred *from,
 	 const struct cred *to)
 LSM_HOOK(int, 0, binder_transfer_file, const struct cred *from,
-	 const struct cred *to, struct file *file)
+	 const struct cred *to, const struct file *file)
 LSM_HOOK(int, 0, ptrace_access_check, struct task_struct *child,
 	 unsigned int mode)
 LSM_HOOK(int, 0, ptrace_traceme, struct task_struct *parent)
diff --git a/include/linux/security.h b/include/linux/security.h
index e2734e9e44d5..79ddeb2a2ff1 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -268,7 +268,7 @@ int security_binder_transaction(const struct cred *from,
 int security_binder_transfer_binder(const struct cred *from,
 				    const struct cred *to);
 int security_binder_transfer_file(const struct cred *from,
-				  const struct cred *to, struct file *file);
+				  const struct cred *to, const struct file *file);
 int security_ptrace_access_check(struct task_struct *child, unsigned int mode);
 int security_ptrace_traceme(struct task_struct *parent);
 int security_capget(struct task_struct *target,
@@ -537,7 +537,7 @@ static inline int security_binder_transfer_binder(const struct cred *from,
 
 static inline int security_binder_transfer_file(const struct cred *from,
 						const struct cred *to,
-						struct file *file)
+						const struct file *file)
 {
 	return 0;
 }
diff --git a/security/security.c b/security/security.c
index d5ff7ff45b77..9e222e8156b1 100644
--- a/security/security.c
+++ b/security/security.c
@@ -840,7 +840,7 @@ int security_binder_transfer_binder(const struct cred *from,
  * Return: Returns 0 if permission is granted.
  */
 int security_binder_transfer_file(const struct cred *from,
-				  const struct cred *to, struct file *file)
+				  const struct cred *to, const struct file *file)
 {
 	return call_int_hook(binder_transfer_file, 0, from, to, file);
 }
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 79b4890e9936..f801b10d0822 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1665,7 +1665,7 @@ static inline int file_path_has_perm(const struct cred *cred,
 }
 
 #ifdef CONFIG_BPF_SYSCALL
-static int bpf_fd_pass(struct file *file, u32 sid);
+static int bpf_fd_pass(const struct file *file, u32 sid);
 #endif
 
 /* Check whether a task can use an open file descriptor to
@@ -1926,7 +1926,7 @@ static inline u32 file_mask_to_av(int mode, int mask)
 }
 
 /* Convert a Linux file to an access vector. */
-static inline u32 file_to_av(struct file *file)
+static inline u32 file_to_av(const struct file *file)
 {
 	u32 av = 0;
 
@@ -2001,7 +2001,7 @@ static int selinux_binder_transfer_binder(const struct cred *from,
 
 static int selinux_binder_transfer_file(const struct cred *from,
 					const struct cred *to,
-					struct file *file)
+					const struct file *file)
 {
 	u32 sid = cred_sid(to);
 	struct file_security_struct *fsec = selinux_file(file);
@@ -6679,7 +6679,7 @@ static u32 bpf_map_fmode_to_av(fmode_t fmode)
  * access the bpf object and that's why we have to add this additional check in
  * selinux_file_receive and selinux_binder_transfer_files.
  */
-static int bpf_fd_pass(struct file *file, u32 sid)
+static int bpf_fd_pass(const struct file *file, u32 sid)
 {
 	struct bpf_security_struct *bpfsec;
 	struct bpf_prog *prog;
-- 
2.34.1