diff options
| author | Kees Cook <kees.cook@canonical.com> | 2010-02-03 15:36:43 -0800 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2010-02-04 14:20:12 +1100 |
| commit | 002345925e6c45861f60db6f4fc6236713fd8847 (patch) | |
| tree | d7849eafe1755116597166bbebf43e2bee86cb76 /security | |
| parent | 0719aaf5ead7555b7b7a4a080ebf2826a871384e (diff) | |
| download | lwn-002345925e6c45861f60db6f4fc6236713fd8847.tar.gz lwn-002345925e6c45861f60db6f4fc6236713fd8847.zip | |
syslog: distinguish between /proc/kmsg and syscalls
This allows the LSM to distinguish between syslog functions originating
from /proc/kmsg access and direct syscalls. By default, the commoncaps
will now no longer require CAP_SYS_ADMIN to read an opened /proc/kmsg
file descriptor. For example the kernel syslog reader can now drop
privileges after opening /proc/kmsg, instead of staying privileged with
CAP_SYS_ADMIN. MAC systems that implement security_syslog have unchanged
behavior.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security')
| -rw-r--r-- | security/commoncap.c | 7 | ||||
| -rw-r--r-- | security/security.c | 4 | ||||
| -rw-r--r-- | security/selinux/hooks.c | 5 | ||||
| -rw-r--r-- | security/smack/smack_lsm.c | 4 |
4 files changed, 13 insertions, 7 deletions
diff --git a/security/commoncap.c b/security/commoncap.c index f800fdb3de94..677fad9d5cba 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -27,6 +27,7 @@ #include <linux/sched.h> #include <linux/prctl.h> #include <linux/securebits.h> +#include <linux/syslog.h> /* * If a non-root user executes a setuid-root binary in @@ -888,12 +889,16 @@ error: /** * cap_syslog - Determine whether syslog function is permitted * @type: Function requested + * @from_file: Whether this request came from an open file (i.e. /proc) * * Determine whether the current process is permitted to use a particular * syslog function, returning 0 if permission is granted, -ve if not. */ -int cap_syslog(int type) +int cap_syslog(int type, bool from_file) { + /* /proc/kmsg can open be opened by CAP_SYS_ADMIN */ + if (type != 1 && from_file) + return 0; if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN)) return -EPERM; return 0; diff --git a/security/security.c b/security/security.c index 440afe5eb54c..971092c06f31 100644 --- a/security/security.c +++ b/security/security.c @@ -203,9 +203,9 @@ int security_quota_on(struct dentry *dentry) return security_ops->quota_on(dentry); } -int security_syslog(int type) +int security_syslog(int type, bool from_file) { - return security_ops->syslog(type); + return security_ops->syslog(type, from_file); } int security_settime(struct timespec *ts, struct timezone *tz) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 9a2ee845e9d4..a4862a0730fa 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -76,6 +76,7 @@ #include <linux/selinux.h> #include <linux/mutex.h> #include <linux/posix-timers.h> +#include <linux/syslog.h> #include "avc.h" #include "objsec.h" @@ -2049,11 +2050,11 @@ static int selinux_quota_on(struct dentry *dentry) return dentry_has_perm(cred, NULL, dentry, FILE__QUOTAON); } -static int selinux_syslog(int type) +static int selinux_syslog(int type, bool from_file) { int rc; - rc = cap_syslog(type); + rc = cap_syslog(type, from_file); if (rc) return rc; diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 529c9ca65878..a5721b373f53 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -157,12 +157,12 @@ static int smack_ptrace_traceme(struct task_struct *ptp) * * Returns 0 on success, error code otherwise. */ -static int smack_syslog(int type) +static int smack_syslog(int type, bool from_file) { int rc; char *sp = current_security(); - rc = cap_syslog(type); + rc = cap_syslog(type, from_file); if (rc != 0) return rc; |