diff options
authorAndi Kleen <ak@linux.intel.com>2011-04-21 17:23:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-04-22 16:17:29 -0700
commit8c9e80ed276fc4b9c9fadf29d8bf6b3576112f1a (patch)
parent8d082f8f3fb89e8a1fcb5120ad98cd9860c8a3e8 (diff)
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 <ak@linux.intel.com> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
5 files changed, 14 insertions, 8 deletions
diff --git a/include/linux/security.h b/include/linux/security.h
index ca02f171673..8ce59ef3e5a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1456,7 +1456,7 @@ struct security_operations {
struct inode *new_dir, struct dentry *new_dentry);
int (*inode_readlink) (struct dentry *dentry);
int (*inode_follow_link) (struct dentry *dentry, struct nameidata *nd);
- int (*inode_permission) (struct inode *inode, int mask);
+ int (*inode_permission) (struct inode *inode, int mask, unsigned flags);
int (*inode_setattr) (struct dentry *dentry, struct iattr *attr);
int (*inode_getattr) (struct vfsmount *mnt, struct dentry *dentry);
int (*inode_setxattr) (struct dentry *dentry, const char *name,
diff --git a/security/capability.c b/security/capability.c
index 2984ea4f776..bbb51156261 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -181,7 +181,7 @@ static int cap_inode_follow_link(struct dentry *dentry,
return 0;
-static int cap_inode_permission(struct inode *inode, int mask)
+static int cap_inode_permission(struct inode *inode, int mask, unsigned flags)
return 0;
diff --git a/security/security.c b/security/security.c
index 101142369db..4ba6d4cc061 100644
--- a/security/security.c
+++ b/security/security.c
@@ -518,16 +518,14 @@ int security_inode_permission(struct inode *inode, int mask)
if (unlikely(IS_PRIVATE(inode)))
return 0;
- return security_ops->inode_permission(inode, mask);
+ return security_ops->inode_permission(inode, mask, 0);
int security_inode_exec_permission(struct inode *inode, unsigned int flags)
if (unlikely(IS_PRIVATE(inode)))
return 0;
- if (flags)
- return -ECHILD;
- return security_ops->inode_permission(inode, MAY_EXEC);
+ return security_ops->inode_permission(inode, MAY_EXEC, flags);
int security_inode_setattr(struct dentry *dentry, struct iattr *attr)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index f9c3764e485..a73f4e46377 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;
ad.u.fs.inode = inode;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index c6f8fcadae0..400a5d5cde6 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -686,7 +686,7 @@ static int smack_inode_rename(struct inode *old_inode,
* Returns 0 if access is permitted, -EACCES otherwise
-static int smack_inode_permission(struct inode *inode, int mask)
+static int smack_inode_permission(struct inode *inode, int mask, unsigned flags)
struct smk_audit_info ad;
@@ -696,6 +696,10 @@ static int smack_inode_permission(struct inode *inode, int mask)
if (mask == 0)
return 0;
+ /* May be droppable after audit */
+ if (flags & IPERM_FLAG_RCU)
+ return -ECHILD;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_FS);
smk_ad_setfield_u_fs_inode(&ad, inode);
return smk_curacc(smk_of_inode(inode), mask, &ad);