These ioctls are equivalent to fcntl(fd, F_SETFD, flags), which SELinux
always allows too. Furthermore, a failed FIOCLEX could result in a file
descriptor being leaked to a process that should not have access to it.
As this patch removes access controls, a policy capability needs to be
enabled in policy to always allow these ioctls.
Based-on-patch-by: Demi Marie Obenour <[email protected]>
Signed-off-by: Richard Haines <[email protected]>
---
V2 Change: Control via a policy capability.
V3 Change: Update switch check.
V4 Change: Use POLICYDB_CAPABILITY_IOCTL_SKIP_CLOEXEC
security/selinux/hooks.c | 6 ++++++
security/selinux/include/policycap.h | 1 +
security/selinux/include/policycap_names.h | 3 ++-
security/selinux/include/security.h | 7 +++++++
4 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 5b6895e4f..d369c2d82 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3745,6 +3745,12 @@ static int selinux_file_ioctl(struct file *file, unsigned int cmd,
CAP_OPT_NONE, true);
break;
+ case FIOCLEX:
+ case FIONCLEX:
+ if (!selinux_policycap_ioctl_skip_cloexec())
+ error = ioctl_has_perm(cred, file, FILE__IOCTL, (u16) cmd);
+ break;
+
/* default case assumes that the command will go
* to the file's ioctl() function.
*/
diff --git a/security/selinux/include/policycap.h b/security/selinux/include/policycap.h
index 2ec038efb..a9e572ca4 100644
--- a/security/selinux/include/policycap.h
+++ b/security/selinux/include/policycap.h
@@ -11,6 +11,7 @@ enum {
POLICYDB_CAPABILITY_CGROUPSECLABEL,
POLICYDB_CAPABILITY_NNP_NOSUID_TRANSITION,
POLICYDB_CAPABILITY_GENFS_SECLABEL_SYMLINKS,
+ POLICYDB_CAPABILITY_IOCTL_SKIP_CLOEXEC,
__POLICYDB_CAPABILITY_MAX
};
#define POLICYDB_CAPABILITY_MAX (__POLICYDB_CAPABILITY_MAX - 1)
diff --git a/security/selinux/include/policycap_names.h b/security/selinux/include/policycap_names.h
index b89289f09..ebd64afe1 100644
--- a/security/selinux/include/policycap_names.h
+++ b/security/selinux/include/policycap_names.h
@@ -12,7 +12,8 @@ const char *selinux_policycap_names[__POLICYDB_CAPABILITY_MAX] = {
"always_check_network",
"cgroup_seclabel",
"nnp_nosuid_transition",
- "genfs_seclabel_symlinks"
+ "genfs_seclabel_symlinks",
+ "ioctl_skip_cloexec"
};
#endif /* _SELINUX_POLICYCAP_NAMES_H_ */
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index ac0ece013..c0d966020 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -219,6 +219,13 @@ static inline bool selinux_policycap_genfs_seclabel_symlinks(void)
return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_GENFS_SECLABEL_SYMLINKS]);
}
+static inline bool selinux_policycap_ioctl_skip_cloexec(void)
+{
+ struct selinux_state *state = &selinux_state;
+
+ return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_IOCTL_SKIP_CLOEXEC]);
+}
+
struct selinux_policy_convert_data;
struct selinux_load_state {
--
2.35.1