From: Richard Haines <richard_c_haines@btinternet.com>
To: paul@paul-moore.com, stephen.smalley.work@gmail.com,
eparis@parisplace.org, demiobenour@gmail.com
Cc: selinux@vger.kernel.org, linux-kernel@vger.kernel.org,
selinux-refpolicy@vger.kernel.org, jeffv@google.com,
Richard Haines <richard_c_haines@btinternet.com>
Subject: [PATCH V3] security/selinux: Always allow FIOCLEX and FIONCLEX
Date: Thu, 24 Feb 2022 10:24:17 +0000 [thread overview]
Message-ID: <20220224102417.42268-1-richard_c_haines@btinternet.com> (raw)
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 <demiobenour@gmail.com>
Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>
---
V2 Change: Control via a policy capability.
V3 Change: Update switch check.
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..44d73dc32 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_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..8a789c22b 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_CLOEXEC]);
+}
+
struct selinux_policy_convert_data;
struct selinux_load_state {
--
2.35.1
next reply other threads:[~2022-02-24 10:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-24 10:24 Richard Haines [this message]
2022-02-25 0:34 ` [PATCH V3] security/selinux: Always allow FIOCLEX and FIONCLEX Paul Moore
2022-02-25 10:01 ` Ondrej Mosnacek
2022-02-25 20:54 ` Paul Moore
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