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selinux: [RFC][PATCH 6/7] security: new LSM hook security_file_g

[RFC][PATCH 6/7] security: new LSM hook security_file_getsecid()

From: Roberto Sassu <roberto.sassu_at_nospam>
Date: Wed Apr 27 2011 - 12:34:14 GMT
To: linux-security-module@vger.kernel.org

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@polito.it>
--- 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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