From 8c9e80ed276fc4b9c9fadf29d8bf6b3576112f1a Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 21 Apr 2011 17:23:19 -0700 Subject: SECURITY: Move exec_permission RCU checks into security modules Right now all RCU walks fall back to reference walk when CONFIG_SECURITY is enabled, even though just the standard capability module is active. This is because security_inode_exec_permission unconditionally fails RCU walks. Move this decision to the low level security module. This requires passing the RCU flags down the security hook. This way at least the capability module and a few easy cases in selinux/smack work with RCU walks with CONFIG_SECURITY=y Signed-off-by: Andi Kleen Acked-by: Eric Paris Signed-off-by: Linus Torvalds --- security/selinux/hooks.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index f9c3764e4859..a73f4e463774 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -2635,7 +2635,7 @@ static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *na return dentry_has_perm(cred, NULL, dentry, FILE__READ); } -static int selinux_inode_permission(struct inode *inode, int mask) +static int selinux_inode_permission(struct inode *inode, int mask, unsigned flags) { const struct cred *cred = current_cred(); struct common_audit_data ad; @@ -2649,6 +2649,10 @@ static int selinux_inode_permission(struct inode *inode, int mask) if (!mask) return 0; + /* May be droppable after audit */ + if (flags & IPERM_FLAG_RCU) + return -ECHILD; + COMMON_AUDIT_DATA_INIT(&ad, FS); ad.u.fs.inode = inode; -- cgit v1.2.3 From 9ade0cf440a1e5800dc68eef2e77b8d9d83a6dff Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Mon, 25 Apr 2011 16:26:29 -0400 Subject: SELINUX: Make selinux cache VFS RCU walks safe Now that the security modules can decide whether they support the dcache RCU walk or not it's possible to make selinux a bit more RCU friendly. The SELinux AVC and security server access decision code is RCU safe. A specific piece of the LSM audit code may not be RCU safe. This patch makes the VFS RCU walk retry if it would hit the non RCU safe chunk of code. It will normally just work under RCU. This is done simply by passing the VFS RCU state as a flag down into the avc_audit() code and returning ECHILD there if it would have an issue. Based-on-patch-by: Andi Kleen Signed-off-by: Eric Paris Signed-off-by: Linus Torvalds --- security/selinux/hooks.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a73f4e463774..f7cf0ea6faea 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1446,8 +1446,11 @@ static int task_has_capability(struct task_struct *tsk, } rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd); - if (audit == SECURITY_CAP_AUDIT) - avc_audit(sid, sid, sclass, av, &avd, rc, &ad); + if (audit == SECURITY_CAP_AUDIT) { + int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad, 0); + if (rc2) + return rc2; + } return rc; } @@ -1467,7 +1470,8 @@ static int task_has_system(struct task_struct *tsk, static int inode_has_perm(const struct cred *cred, struct inode *inode, u32 perms, - struct common_audit_data *adp) + struct common_audit_data *adp, + unsigned flags) { struct inode_security_struct *isec; struct common_audit_data ad; @@ -1487,7 +1491,7 @@ static int inode_has_perm(const struct cred *cred, ad.u.fs.inode = inode; } - return avc_has_perm(sid, isec->sid, isec->sclass, perms, adp); + return avc_has_perm_flags(sid, isec->sid, isec->sclass, perms, adp, flags); } /* Same as inode_has_perm, but pass explicit audit data containing @@ -1504,7 +1508,7 @@ static inline int dentry_has_perm(const struct cred *cred, COMMON_AUDIT_DATA_INIT(&ad, FS); ad.u.fs.path.mnt = mnt; ad.u.fs.path.dentry = dentry; - return inode_has_perm(cred, inode, av, &ad); + return inode_has_perm(cred, inode, av, &ad, 0); } /* Check whether a task can use an open file descriptor to @@ -1540,7 +1544,7 @@ static int file_has_perm(const struct cred *cred, /* av is zero if only checking access to the descriptor. */ rc = 0; if (av) - rc = inode_has_perm(cred, inode, av, &ad); + rc = inode_has_perm(cred, inode, av, &ad, 0); out: return rc; @@ -2103,7 +2107,7 @@ static inline void flush_unauthorized_files(const struct cred *cred, file = file_priv->file; inode = file->f_path.dentry->d_inode; if (inode_has_perm(cred, inode, - FILE__READ | FILE__WRITE, NULL)) { + FILE__READ | FILE__WRITE, NULL, 0)) { drop_tty = 1; } } @@ -2649,10 +2653,6 @@ static int selinux_inode_permission(struct inode *inode, int mask, unsigned flag if (!mask) return 0; - /* May be droppable after audit */ - if (flags & IPERM_FLAG_RCU) - return -ECHILD; - COMMON_AUDIT_DATA_INIT(&ad, FS); ad.u.fs.inode = inode; @@ -2661,7 +2661,7 @@ static int selinux_inode_permission(struct inode *inode, int mask, unsigned flag perms = file_mask_to_av(inode->i_mode, mask); - return inode_has_perm(cred, inode, perms, &ad); + return inode_has_perm(cred, inode, perms, &ad, flags); } static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) @@ -3209,7 +3209,7 @@ static int selinux_dentry_open(struct file *file, const struct cred *cred) * new inode label or new policy. * This check is not redundant - do not remove. */ - return inode_has_perm(cred, inode, open_file_to_av(file), NULL); + return inode_has_perm(cred, inode, open_file_to_av(file), NULL, 0); } /* task security operations */ -- cgit v1.2.3 From cb1e922fa104bb0bb3aa5fc6ca7f7e070f3b55e9 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 28 Apr 2011 15:11:21 -0400 Subject: SELinux: pass last path component in may_create New inodes are created in a two stage process. We first will compute the label on a new inode in security_inode_create() and check if the operation is allowed. We will then actually re-compute that same label and apply it in security_inode_init_security(). The change to do new label calculations based in part on the last component of the path name only passed the path component information all the way down the security_inode_init_security hook. Down the security_inode_create hook the path information did not make it past may_create. Thus the two calculations came up differently and the permissions check might not actually be against the label that is created. Pass and use the same information in both places to harmonize the calculations and checks. Reported-by: Dominick Grift Signed-off-by: Eric Paris --- security/selinux/hooks.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'security/selinux/hooks.c') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index d52a92507412..9a93af81a0c3 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1573,7 +1573,8 @@ static int may_create(struct inode *dir, return rc; if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { - rc = security_transition_sid(sid, dsec->sid, tclass, NULL, &newsid); + rc = security_transition_sid(sid, dsec->sid, tclass, + &dentry->d_name, &newsid); if (rc) return rc; } -- cgit v1.2.3