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| author | Serge E. Hallyn <serge@hallyn.com> | 2010-11-25 17:11:32 +0000 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2010-11-29 08:35:12 +1100 |
| commit | ce6ada35bdf710d16582cc4869c26722547e6f11 (patch) | |
| tree | c2b5fd46c883f4b7285b191bac55940022662b43 | |
| parent | 1d6d75684d869406e5bb2ac5d3ed9454f52d0cab (diff) | |
| download | linux-ce6ada35bdf710d16582cc4869c26722547e6f11.tar.gz | |
security: Define CAP_SYSLOG
Privileged syslog operations currently require CAP_SYS_ADMIN. Split this off into a new CAP_SYSLOG privilege which we can sanely take away from a container through the capability bounding set. With this patch, an lxc container can be prevented from messing with the host's syslog (i.e. dmesg -c). Changelog: mar 12 2010: add selinux capability2:cap_syslog perm Changelog: nov 22 2010: . port to new kernel . add a WARN_ONCE if userspace isn't using CAP_SYSLOG Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com> Acked-by: Andrew G. Morgan <morgan@kernel.org> Acked-By: Kees Cook <kees.cook@canonical.com> Cc: James Morris <jmorris@namei.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: "Christopher J. PeBenito" <cpebenito@tresys.com> Cc: Eric Paris <eparis@parisplace.org> Signed-off-by: James Morris <jmorris@namei.org>
| -rw-r--r-- | include/linux/capability.h | 7 | ||||
| -rw-r--r-- | kernel/printk.c | 8 | ||||
| -rw-r--r-- | security/selinux/include/classmap.h | 2 |
3 files changed, 13 insertions, 4 deletions
diff --git a/include/linux/capability.h b/include/linux/capability.h index 90012b9ddbf3..fb16a3699b99 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -246,7 +246,6 @@ struct cpu_vfs_cap_data { /* Allow configuration of the secure attention key */ /* Allow administration of the random device */ /* Allow examination and configuration of disk quotas */ -/* Allow configuring the kernel's syslog (printk behaviour) */ /* Allow setting the domainname */ /* Allow setting the hostname */ /* Allow calling bdflush() */ @@ -352,7 +351,11 @@ struct cpu_vfs_cap_data { #define CAP_MAC_ADMIN 33 -#define CAP_LAST_CAP CAP_MAC_ADMIN +/* Allow configuring the kernel's syslog (printk behaviour) */ + +#define CAP_SYSLOG 34 + +#define CAP_LAST_CAP CAP_SYSLOG #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP) diff --git a/kernel/printk.c b/kernel/printk.c index 9a2264fc42ca..0712380737b3 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -283,8 +283,14 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) return -EPERM; if ((type != SYSLOG_ACTION_READ_ALL && type != SYSLOG_ACTION_SIZE_BUFFER) && - !capable(CAP_SYS_ADMIN)) + !capable(CAP_SYSLOG)) { + /* remove after 2.6.38 */ + if (capable(CAP_SYS_ADMIN)) + WARN_ONCE(1, "Attempt to access syslog with " + "CAP_SYS_ADMIN but no CAP_SYSLOG " + "(deprecated and denied).\n"); return -EPERM; + } } error = security_syslog(type); diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index 8858d2b2d4b6..7ed3663332ec 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -142,7 +142,7 @@ struct security_class_mapping secclass_map[] = { "node_bind", "name_connect", NULL } }, { "memprotect", { "mmap_zero", NULL } }, { "peer", { "recv", NULL } }, - { "capability2", { "mac_override", "mac_admin", NULL } }, + { "capability2", { "mac_override", "mac_admin", "syslog", NULL } }, { "kernel_service", { "use_as_override", "create_files_as", NULL } }, { "tun_socket", { COMMON_SOCK_PERMS, NULL } }, |