Commit 7470d0d1 authored by Christian Göttsche's avatar Christian Göttsche Committed by Paul Moore
Browse files

selinux: allow kernfs symlinks to inherit parent directory context 



Currently symlinks on kernel filesystems, like sysfs, are labeled on
creation with the parent filesystem root sid.

Allow symlinks to inherit the parent directory context, so fine-grained
kernfs labeling can be applied to symlinks too and checking contexts
doesn't complain about them.

For backward-compatibility this behavior is contained in a new policy
capability: genfs_seclabel_symlinks

Signed-off-by: default avatarChristian Göttsche <cgzones@googlemail.com>
Acked-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 06c2efe2

security/selinux/hooks.c

+3 −1
Original line number Diff line number Diff line
@@ -1478,7 +1478,9 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent 
		/* Default to the fs superblock SID. */

		sid = sbsec->sid;



		if ((sbsec->flags & SE_SBGENFS) && !S_ISLNK(inode->i_mode)) {

		if ((sbsec->flags & SE_SBGENFS) &&

		     (!S_ISLNK(inode->i_mode) ||

		      selinux_policycap_genfs_seclabel_symlinks())) {

			/* We must have a dentry to determine the label on

			 * procfs inodes */

			if (opt_dentry) {

security/selinux/include/security.h

+8 −0
Original line number Diff line number Diff line
@@ -79,6 +79,7 @@ enum { 
	POLICYDB_CAPABILITY_ALWAYSNETWORK,

	POLICYDB_CAPABILITY_CGROUPSECLABEL,

	POLICYDB_CAPABILITY_NNP_NOSUID_TRANSITION,

	POLICYDB_CAPABILITY_GENFS_SECLABEL_SYMLINKS,

	__POLICYDB_CAPABILITY_MAX

};

#define POLICYDB_CAPABILITY_MAX (__POLICYDB_CAPABILITY_MAX - 1)
@@ -213,6 +214,13 @@ static inline bool selinux_policycap_nnp_nosuid_transition(void) 
	return state->policycap[POLICYDB_CAPABILITY_NNP_NOSUID_TRANSITION];

}



static inline bool selinux_policycap_genfs_seclabel_symlinks(void)

{

	struct selinux_state *state = &selinux_state;



	return state->policycap[POLICYDB_CAPABILITY_GENFS_SECLABEL_SYMLINKS];

}



int security_mls_enabled(struct selinux_state *state);

int security_load_policy(struct selinux_state *state,

			 void *data, size_t len);

security/selinux/ss/services.c

+2 −1
Original line number Diff line number Diff line
@@ -72,7 +72,8 @@ const char *selinux_policycap_names[__POLICYDB_CAPABILITY_MAX] = { 
	"extended_socket_class",

	"always_check_network",

	"cgroup_seclabel",

	"nnp_nosuid_transition"

	"nnp_nosuid_transition",

	"genfs_seclabel_symlinks"

};



static struct selinux_ss selinux_ss;

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