| Message ID | 20220225175438.302365-1-richard_c_haines@btinternet.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | [V4] security/selinux: Always allow FIOCLEX and FIONCLEX | expand |
On Fri, Feb 25, 2022 at 12:54 PM Richard Haines <richard_c_haines@btinternet.com> wrote: > > 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. > 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(-) Merged into selinux/next, thanks everyone!
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 {
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. 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(-)