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authorStephen Smalley <sds@tycho.nsa.gov>2015-06-04 23:22:17 +0300
committerPaul Moore <pmoore@redhat.com>2015-06-04 23:22:17 +0300
commit134509d54e4e98888be2697a92cb4b48957b792b (patch)
treebd4d47b5287f2b3e846d377e21bb5ad77486d774
parent6c6d2e9bde1c1c87a7ead806f8f5e2181d41a652 (diff)
downloadlinux-134509d54e4e98888be2697a92cb4b48957b792b.tar.xz
selinux: enable per-file labeling for debugfs files.
Add support for per-file labeling of debugfs files so that we can distinguish them in policy. This is particularly important in Android where certain debugfs files have to be writable by apps and therefore the debugfs directory tree can be read and searched by all. Since debugfs is entirely kernel-generated, the directory tree is immutable by userspace, and the inodes are pinned in memory, we can simply use the same approach as with proc and label the inodes from policy based on pathname from the root of the debugfs filesystem. Generalize the existing labeling support used for proc and reuse it for debugfs too. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <pmoore@redhat.com>
-rw-r--r--security/selinux/hooks.c43
-rw-r--r--security/selinux/include/security.h1
2 files changed, 22 insertions, 22 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index cf2cc0dca9b7..ec39b9ab6569 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -724,7 +724,10 @@ static int selinux_set_mnt_opts(struct super_block *sb,
}
if (strcmp(sb->s_type->name, "proc") == 0)
- sbsec->flags |= SE_SBPROC;
+ sbsec->flags |= SE_SBPROC | SE_SBGENFS;
+
+ if (strcmp(sb->s_type->name, "debugfs") == 0)
+ sbsec->flags |= SE_SBGENFS;
if (!sbsec->behavior) {
/*
@@ -1232,12 +1235,13 @@ static inline u16 socket_type_to_security_class(int family, int type, int protoc
return SECCLASS_SOCKET;
}
-#ifdef CONFIG_PROC_FS
-static int selinux_proc_get_sid(struct dentry *dentry,
- u16 tclass,
- u32 *sid)
+static int selinux_genfs_get_sid(struct dentry *dentry,
+ u16 tclass,
+ u16 flags,
+ u32 *sid)
{
int rc;
+ struct super_block *sb = dentry->d_inode->i_sb;
char *buffer, *path;
buffer = (char *)__get_free_page(GFP_KERNEL);
@@ -1248,26 +1252,20 @@ static int selinux_proc_get_sid(struct dentry *dentry,
if (IS_ERR(path))
rc = PTR_ERR(path);
else {
- /* each process gets a /proc/PID/ entry. Strip off the
- * PID part to get a valid selinux labeling.
- * e.g. /proc/1/net/rpc/nfs -> /net/rpc/nfs */
- while (path[1] >= '0' && path[1] <= '9') {
- path[1] = '/';
- path++;
+ if (flags & SE_SBPROC) {
+ /* each process gets a /proc/PID/ entry. Strip off the
+ * PID part to get a valid selinux labeling.
+ * e.g. /proc/1/net/rpc/nfs -> /net/rpc/nfs */
+ while (path[1] >= '0' && path[1] <= '9') {
+ path[1] = '/';
+ path++;
+ }
}
- rc = security_genfs_sid("proc", path, tclass, sid);
+ rc = security_genfs_sid(sb->s_type->name, path, tclass, sid);
}
free_page((unsigned long)buffer);
return rc;
}
-#else
-static int selinux_proc_get_sid(struct dentry *dentry,
- u16 tclass,
- u32 *sid)
-{
- return -EINVAL;
-}
-#endif
/* The inode's security attributes must be initialized before first use. */
static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dentry)
@@ -1424,7 +1422,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
/* Default to the fs superblock SID. */
isec->sid = sbsec->sid;
- if ((sbsec->flags & SE_SBPROC) && !S_ISLNK(inode->i_mode)) {
+ if ((sbsec->flags & SE_SBGENFS) && !S_ISLNK(inode->i_mode)) {
/* We must have a dentry to determine the label on
* procfs inodes */
if (opt_dentry)
@@ -1447,7 +1445,8 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
if (!dentry)
goto out_unlock;
isec->sclass = inode_mode_to_security_class(inode->i_mode);
- rc = selinux_proc_get_sid(dentry, isec->sclass, &sid);
+ rc = selinux_genfs_get_sid(dentry, isec->sclass,
+ sbsec->flags, &sid);
dput(dentry);
if (rc)
goto out_unlock;
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index d1e0b239b602..36993ad1c067 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -56,6 +56,7 @@
/* Non-mount related flags */
#define SE_SBINITIALIZED 0x0100
#define SE_SBPROC 0x0200
+#define SE_SBGENFS 0x0400
#define CONTEXT_STR "context="
#define FSCONTEXT_STR "fscontext="