From 0c6cfa622cf57109607f3416b286b6b55561a2ea Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Fri, 21 Sep 2018 17:17:16 -0700 Subject: [PATCH] SELinux: Abstract use of cred security blob Don't use the cred->security pointer directly. Provide a helper function that provides the security blob pointer. Signed-off-by: Casey Schaufler Reviewed-by: Kees Cook [kees: adjusted for ordered init series] Signed-off-by: Kees Cook --- security/selinux/hooks.c | 54 +++++++++++++++---------------- security/selinux/include/objsec.h | 5 +++ security/selinux/xfrm.c | 4 +-- 3 files changed, 34 insertions(+), 29 deletions(-) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index c5d9fbbb5e5b..beec1de5c2da 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -226,7 +226,7 @@ static inline u32 cred_sid(const struct cred *cred) { const struct task_security_struct *tsec; - tsec = cred->security; + tsec = selinux_cred(cred); return tsec->sid; } @@ -498,7 +498,7 @@ static int may_context_mount_sb_relabel(u32 sid, struct superblock_security_struct *sbsec, const struct cred *cred) { - const struct task_security_struct *tsec = cred->security; + const struct task_security_struct *tsec = selinux_cred(cred); int rc; rc = avc_has_perm(&selinux_state, @@ -517,7 +517,7 @@ static int may_context_mount_inode_relabel(u32 sid, struct superblock_security_struct *sbsec, const struct cred *cred) { - const struct task_security_struct *tsec = cred->security; + const struct task_security_struct *tsec = selinux_cred(cred); int rc; rc = avc_has_perm(&selinux_state, tsec->sid, sbsec->sid, SECCLASS_FILESYSTEM, @@ -1803,7 +1803,7 @@ static int may_create(struct inode *dir, struct dentry *dentry, u16 tclass) { - const struct task_security_struct *tsec = current_security(); + const struct task_security_struct *tsec = selinux_cred(current_cred()); struct inode_security_struct *dsec; struct superblock_security_struct *sbsec; u32 sid, newsid; @@ -1825,7 +1825,7 @@ static int may_create(struct inode *dir, if (rc) return rc; - rc = selinux_determine_inode_label(current_security(), dir, + rc = selinux_determine_inode_label(selinux_cred(current_cred()), dir, &dentry->d_name, tclass, &newsid); if (rc) return rc; @@ -2332,8 +2332,8 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm) if (bprm->called_set_creds) return 0; - old_tsec = current_security(); - new_tsec = bprm->cred->security; + old_tsec = selinux_cred(current_cred()); + new_tsec = selinux_cred(bprm->cred); isec = inode_security(inode); /* Default to the current task SID. */ @@ -2497,7 +2497,7 @@ static void selinux_bprm_committing_creds(struct linux_binprm *bprm) struct rlimit *rlim, *initrlim; int rc, i; - new_tsec = bprm->cred->security; + new_tsec = selinux_cred(bprm->cred); if (new_tsec->sid == new_tsec->osid) return; @@ -2540,7 +2540,7 @@ static void selinux_bprm_committing_creds(struct linux_binprm *bprm) */ static void selinux_bprm_committed_creds(struct linux_binprm *bprm) { - const struct task_security_struct *tsec = current_security(); + const struct task_security_struct *tsec = selinux_cred(current_cred()); struct itimerval itimer; u32 osid, sid; int rc, i; @@ -2777,7 +2777,7 @@ static int selinux_dentry_init_security(struct dentry *dentry, int mode, u32 newsid; int rc; - rc = selinux_determine_inode_label(current_security(), + rc = selinux_determine_inode_label(selinux_cred(current_cred()), d_inode(dentry->d_parent), name, inode_mode_to_security_class(mode), &newsid); @@ -2797,14 +2797,14 @@ static int selinux_dentry_create_files_as(struct dentry *dentry, int mode, int rc; struct task_security_struct *tsec; - rc = selinux_determine_inode_label(old->security, + rc = selinux_determine_inode_label(selinux_cred(old), d_inode(dentry->d_parent), name, inode_mode_to_security_class(mode), &newsid); if (rc) return rc; - tsec = new->security; + tsec = selinux_cred(new); tsec->create_sid = newsid; return 0; } @@ -2814,7 +2814,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir, const char **name, void **value, size_t *len) { - const struct task_security_struct *tsec = current_security(); + const struct task_security_struct *tsec = selinux_cred(current_cred()); struct superblock_security_struct *sbsec; u32 newsid, clen; int rc; @@ -2824,7 +2824,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir, newsid = tsec->create_sid; - rc = selinux_determine_inode_label(current_security(), + rc = selinux_determine_inode_label(selinux_cred(current_cred()), dir, qstr, inode_mode_to_security_class(inode->i_mode), &newsid); @@ -3286,7 +3286,7 @@ static int selinux_inode_copy_up(struct dentry *src, struct cred **new) return -ENOMEM; } - tsec = new_creds->security; + tsec = selinux_cred(new_creds); /* Get label from overlay inode and set it in create_sid */ selinux_inode_getsecid(d_inode(src), &sid); tsec->create_sid = sid; @@ -3706,7 +3706,7 @@ static int selinux_cred_alloc_blank(struct cred *cred, gfp_t gfp) */ static void selinux_cred_free(struct cred *cred) { - struct task_security_struct *tsec = cred->security; + struct task_security_struct *tsec = selinux_cred(cred); /* * cred->security == NULL if security_cred_alloc_blank() or @@ -3726,7 +3726,7 @@ static int selinux_cred_prepare(struct cred *new, const struct cred *old, const struct task_security_struct *old_tsec; struct task_security_struct *tsec; - old_tsec = old->security; + old_tsec = selinux_cred(old); tsec = kmemdup(old_tsec, sizeof(struct task_security_struct), gfp); if (!tsec) @@ -3741,8 +3741,8 @@ static int selinux_cred_prepare(struct cred *new, const struct cred *old, */ static void selinux_cred_transfer(struct cred *new, const struct cred *old) { - const struct task_security_struct *old_tsec = old->security; - struct task_security_struct *tsec = new->security; + const struct task_security_struct *old_tsec = selinux_cred(old); + struct task_security_struct *tsec = selinux_cred(new); *tsec = *old_tsec; } @@ -3758,7 +3758,7 @@ static void selinux_cred_getsecid(const struct cred *c, u32 *secid) */ static int selinux_kernel_act_as(struct cred *new, u32 secid) { - struct task_security_struct *tsec = new->security; + struct task_security_struct *tsec = selinux_cred(new); u32 sid = current_sid(); int ret; @@ -3783,7 +3783,7 @@ static int selinux_kernel_act_as(struct cred *new, u32 secid) static int selinux_kernel_create_files_as(struct cred *new, struct inode *inode) { struct inode_security_struct *isec = inode_security(inode); - struct task_security_struct *tsec = new->security; + struct task_security_struct *tsec = selinux_cred(new); u32 sid = current_sid(); int ret; @@ -4332,7 +4332,7 @@ static int sock_has_perm(struct sock *sk, u32 perms) static int selinux_socket_create(int family, int type, int protocol, int kern) { - const struct task_security_struct *tsec = current_security(); + const struct task_security_struct *tsec = selinux_cred(current_cred()); u32 newsid; u16 secclass; int rc; @@ -4352,7 +4352,7 @@ static int selinux_socket_create(int family, int type, static int selinux_socket_post_create(struct socket *sock, int family, int type, int protocol, int kern) { - const struct task_security_struct *tsec = current_security(); + const struct task_security_struct *tsec = selinux_cred(current_cred()); struct inode_security_struct *isec = inode_security_novalidate(SOCK_INODE(sock)); struct sk_security_struct *sksec; u16 sclass = socket_type_to_security_class(family, type, protocol); @@ -5233,7 +5233,7 @@ static int selinux_secmark_relabel_packet(u32 sid) const struct task_security_struct *__tsec; u32 tsid; - __tsec = current_security(); + __tsec = selinux_cred(current_cred()); tsid = __tsec->sid; return avc_has_perm(&selinux_state, @@ -6170,7 +6170,7 @@ static int selinux_getprocattr(struct task_struct *p, unsigned len; rcu_read_lock(); - __tsec = __task_cred(p)->security; + __tsec = selinux_cred(__task_cred(p)); if (current != p) { error = avc_has_perm(&selinux_state, @@ -6293,7 +6293,7 @@ static int selinux_setprocattr(const char *name, void *value, size_t size) operation. See selinux_bprm_set_creds for the execve checks and may_create for the file creation checks. The operation will then fail if the context is not permitted. */ - tsec = new->security; + tsec = selinux_cred(new); if (!strcmp(name, "exec")) { tsec->exec_sid = sid; } else if (!strcmp(name, "fscreate")) { @@ -6422,7 +6422,7 @@ static int selinux_key_alloc(struct key *k, const struct cred *cred, if (!ksec) return -ENOMEM; - tsec = cred->security; + tsec = selinux_cred(cred); if (tsec->keycreate_sid) ksec->sid = tsec->keycreate_sid; else diff --git a/security/selinux/include/objsec.h b/security/selinux/include/objsec.h index cc5e26b0161b..734b6833bdff 100644 --- a/security/selinux/include/objsec.h +++ b/security/selinux/include/objsec.h @@ -158,4 +158,9 @@ struct bpf_security_struct { u32 sid; /*SID of bpf obj creater*/ }; +static inline struct task_security_struct *selinux_cred(const struct cred *cred) +{ + return cred->security; +} + #endif /* _SELINUX_OBJSEC_H_ */ diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c index bd7d18bdb147..7c57cb7e4146 100644 --- a/security/selinux/xfrm.c +++ b/security/selinux/xfrm.c @@ -79,7 +79,7 @@ static int selinux_xfrm_alloc_user(struct xfrm_sec_ctx **ctxp, gfp_t gfp) { int rc; - const struct task_security_struct *tsec = current_security(); + const struct task_security_struct *tsec = selinux_cred(current_cred()); struct xfrm_sec_ctx *ctx = NULL; u32 str_len; @@ -138,7 +138,7 @@ static void selinux_xfrm_free(struct xfrm_sec_ctx *ctx) */ static int selinux_xfrm_delete(struct xfrm_sec_ctx *ctx) { - const struct task_security_struct *tsec = current_security(); + const struct task_security_struct *tsec = selinux_cred(current_cred()); if (!ctx) return 0;