From 00f84f3f2e9d088f06722f4351d67f5f577abe22 Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Mon, 23 Dec 2013 11:07:10 -0800 Subject: Smack: Make the syslog control configurable The syslog control requires that the calling proccess have the floor ("_") Smack label. Tizen does not run any processes except for kernel helpers with the floor label. This changes allows the admin to configure a specific label for syslog. The default value is the star ("*") label, effectively removing the restriction. The value can be set using smackfs/syslog for anyone who wants a more restrictive behavior. Targeted for git://git.gitorious.org/smack-next/kernel.git Signed-off-by: Casey Schaufler --- security/smack/smack.h | 5 ++- security/smack/smack_lsm.c | 4 +- security/smack/smackfs.c | 103 +++++++++++++++++++++++++++++++++++++++++---- 3 files changed, 99 insertions(+), 13 deletions(-) (limited to 'security') diff --git a/security/smack/smack.h b/security/smack/smack.h index 364cc64fce71..d072fd32212d 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -241,7 +241,8 @@ u32 smack_to_secid(const char *); extern int smack_cipso_direct; extern int smack_cipso_mapped; extern struct smack_known *smack_net_ambient; -extern char *smack_onlycap; +extern struct smack_known *smack_onlycap; +extern struct smack_known *smack_syslog_label; extern const char *smack_cipso_option; extern struct smack_known smack_known_floor; @@ -312,7 +313,7 @@ static inline int smack_privileged(int cap) if (!capable(cap)) return 0; - if (smack_onlycap == NULL || smack_onlycap == skp->smk_known) + if (smack_onlycap == NULL || smack_onlycap == skp) return 1; return 0; } diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 62ebf4f8a6c7..67b7381d0244 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -219,8 +219,6 @@ static int smack_ptrace_traceme(struct task_struct *ptp) * smack_syslog - Smack approval on syslog * @type: message type * - * Require that the task has the floor label - * * Returns 0 on success, error code otherwise. */ static int smack_syslog(int typefrom_file) @@ -231,7 +229,7 @@ static int smack_syslog(int typefrom_file) if (smack_privileged(CAP_MAC_OVERRIDE)) return 0; - if (skp != &smack_known_floor) + if (smack_syslog_label != NULL && smack_syslog_label != skp) rc = -EACCES; return rc; diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 1c89ade186b6..f5a6bb8e2828 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -52,6 +52,7 @@ enum smk_inos { SMK_CIPSO2 = 17, /* load long label -> CIPSO mapping */ SMK_REVOKE_SUBJ = 18, /* set rules with subject label to '-' */ SMK_CHANGE_RULE = 19, /* change or add rules (long labels) */ + SMK_SYSLOG = 20, /* change syslog label) */ }; /* @@ -59,6 +60,7 @@ enum smk_inos { */ static DEFINE_MUTEX(smack_cipso_lock); static DEFINE_MUTEX(smack_ambient_lock); +static DEFINE_MUTEX(smack_syslog_lock); static DEFINE_MUTEX(smk_netlbladdr_lock); /* @@ -90,7 +92,13 @@ int smack_cipso_mapped = SMACK_CIPSO_MAPPED_DEFAULT; * everyone. It is expected that the hat (^) label * will be used if any label is used. */ -char *smack_onlycap; +struct smack_known *smack_onlycap; + +/* + * If this value is set restrict syslog use to the label specified. + * It can be reset via smackfs/syslog + */ +struct smack_known *smack_syslog_label; /* * Certain IP addresses may be designated as single label hosts. @@ -1603,7 +1611,7 @@ static const struct file_operations smk_ambient_ops = { }; /** - * smk_read_onlycap - read() for /smack/onlycap + * smk_read_onlycap - read() for smackfs/onlycap * @filp: file pointer, not actually used * @buf: where to put the result * @cn: maximum to send along @@ -1622,7 +1630,7 @@ static ssize_t smk_read_onlycap(struct file *filp, char __user *buf, return 0; if (smack_onlycap != NULL) - smack = smack_onlycap; + smack = smack_onlycap->smk_known; asize = strlen(smack) + 1; @@ -1633,7 +1641,7 @@ static ssize_t smk_read_onlycap(struct file *filp, char __user *buf, } /** - * smk_write_onlycap - write() for /smack/onlycap + * smk_write_onlycap - write() for smackfs/onlycap * @file: file pointer, not actually used * @buf: where to get the data from * @count: bytes sent @@ -1656,7 +1664,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf, * explicitly for clarity. The smk_access() implementation * would use smk_access(smack_onlycap, MAY_WRITE) */ - if (smack_onlycap != NULL && smack_onlycap != skp->smk_known) + if (smack_onlycap != NULL && smack_onlycap != skp) return -EPERM; data = kzalloc(count, GFP_KERNEL); @@ -1676,7 +1684,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf, if (copy_from_user(data, buf, count) != 0) rc = -EFAULT; else - smack_onlycap = smk_import(data, count); + smack_onlycap = smk_import_entry(data, count); kfree(data); return rc; @@ -2159,12 +2167,89 @@ static const struct file_operations smk_change_rule_ops = { }; /** - * smk_fill_super - fill the /smackfs superblock + * smk_read_syslog - read() for smackfs/syslog + * @filp: file pointer, not actually used + * @buf: where to put the result + * @cn: maximum to send along + * @ppos: where to start + * + * Returns number of bytes read or error code, as appropriate + */ +static ssize_t smk_read_syslog(struct file *filp, char __user *buf, + size_t cn, loff_t *ppos) +{ + struct smack_known *skp; + ssize_t rc = -EINVAL; + int asize; + + if (*ppos != 0) + return 0; + + if (smack_syslog_label == NULL) + skp = &smack_known_star; + else + skp = smack_syslog_label; + + asize = strlen(skp->smk_known) + 1; + + if (cn >= asize) + rc = simple_read_from_buffer(buf, cn, ppos, skp->smk_known, + asize); + + return rc; +} + +/** + * smk_write_syslog - write() for smackfs/syslog + * @file: file pointer, not actually used + * @buf: where to get the data from + * @count: bytes sent + * @ppos: where to start + * + * Returns number of bytes written or error code, as appropriate + */ +static ssize_t smk_write_syslog(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + char *data; + struct smack_known *skp; + int rc = count; + + if (!smack_privileged(CAP_MAC_ADMIN)) + return -EPERM; + + data = kzalloc(count, GFP_KERNEL); + if (data == NULL) + return -ENOMEM; + + if (copy_from_user(data, buf, count) != 0) + rc = -EFAULT; + else { + skp = smk_import_entry(data, count); + if (skp == NULL) + rc = -EINVAL; + else + smack_syslog_label = smk_import_entry(data, count); + } + + kfree(data); + return rc; +} + +static const struct file_operations smk_syslog_ops = { + .read = smk_read_syslog, + .write = smk_write_syslog, + .llseek = default_llseek, +}; + + +/** + * smk_fill_super - fill the smackfs superblock * @sb: the empty superblock * @data: unused * @silent: unused * - * Fill in the well known entries for /smack + * Fill in the well known entries for the smack filesystem * * Returns 0 on success, an error code on failure */ @@ -2209,6 +2294,8 @@ static int smk_fill_super(struct super_block *sb, void *data, int silent) S_IRUGO|S_IWUSR}, [SMK_CHANGE_RULE] = { "change-rule", &smk_change_rule_ops, S_IRUGO|S_IWUSR}, + [SMK_SYSLOG] = { + "syslog", &smk_syslog_ops, S_IRUGO|S_IWUSR}, /* last one */ {""} }; -- cgit v1.2.3