From 1880eff77e7a7cb46c68fae7cfa33f72f0a6e70e Mon Sep 17 00:00:00 2001 From: Casey Schaufler Date: Tue, 5 Jun 2012 15:28:30 -0700 Subject: Smack: onlycap limits on CAP_MAC_ADMIN Smack is integrated with the POSIX capabilities scheme, using the capabilities CAP_MAC_OVERRIDE and CAP_MAC_ADMIN to determine if a process is allowed to ignore Smack checks or change Smack related data respectively. Smack provides an additional restriction that if an onlycap value is set by writing to /smack/onlycap only tasks with that Smack label are allowed to use CAP_MAC_OVERRIDE. This change adds CAP_MAC_ADMIN as a capability that is affected by the onlycap mechanism. Targeted for git://git.gitorious.org/smack-next/kernel.git Signed-off-by: Casey Schaufler --- security/smack/smack.h | 13 +++++++++++++ security/smack/smack_access.c | 9 ++------- security/smack/smack_lsm.c | 17 +++++++++-------- security/smack/smackfs.c | 21 ++++++++++----------- 4 files changed, 34 insertions(+), 26 deletions(-) diff --git a/security/smack/smack.h b/security/smack/smack.h index 76feb31eb823..99b36124f712 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -282,6 +282,19 @@ static inline char *smk_of_current(void) return smk_of_task(current_security()); } +/* + * Is the task privileged and allowed to be privileged + * by the onlycap rule. + */ +static inline int smack_privileged(int cap) +{ + if (!capable(cap)) + return 0; + if (smack_onlycap == NULL || smack_onlycap == smk_of_current()) + return 1; + return 0; +} + /* * logging functions */ diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c index 9f3705e92712..db14689a21e0 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -220,14 +220,9 @@ int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) } /* - * Return if a specific label has been designated as the - * only one that gets privilege and current does not - * have that label. + * Allow for priviliged to override policy. */ - if (smack_onlycap != NULL && smack_onlycap != sp) - goto out_audit; - - if (capable(CAP_MAC_OVERRIDE)) + if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE)) rc = 0; out_audit: diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 29bb4e7fa5e8..8221514cc997 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -217,7 +217,7 @@ static int smack_syslog(int typefrom_file) int rc = 0; char *sp = smk_of_current(); - if (capable(CAP_MAC_OVERRIDE)) + if (smack_privileged(CAP_MAC_OVERRIDE)) return 0; if (sp != smack_known_floor.smk_known) @@ -821,7 +821,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name, strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 || strcmp(name, XATTR_NAME_SMACKEXEC) == 0 || strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { - if (!capable(CAP_MAC_ADMIN)) + if (!smack_privileged(CAP_MAC_ADMIN)) rc = -EPERM; /* * check label validity here so import wont fail on @@ -831,7 +831,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name, smk_import(value, size) == NULL) rc = -EINVAL; } else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) { - if (!capable(CAP_MAC_ADMIN)) + if (!smack_privileged(CAP_MAC_ADMIN)) rc = -EPERM; if (size != TRANS_TRUE_SIZE || strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0) @@ -927,7 +927,7 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name) strcmp(name, XATTR_NAME_SMACKEXEC) == 0 || strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 || strcmp(name, XATTR_NAME_SMACKMMAP)) { - if (!capable(CAP_MAC_ADMIN)) + if (!smack_privileged(CAP_MAC_ADMIN)) rc = -EPERM; } else rc = cap_inode_removexattr(dentry, name); @@ -1716,7 +1716,8 @@ static int smack_task_wait(struct task_struct *p) * state into account in the decision as well as * the smack value. */ - if (capable(CAP_MAC_OVERRIDE) || has_capability(p, CAP_MAC_OVERRIDE)) + if (smack_privileged(CAP_MAC_OVERRIDE) || + has_capability(p, CAP_MAC_OVERRIDE)) rc = 0; /* we log only if we didn't get overriden */ out_log: @@ -2717,7 +2718,7 @@ static int smack_setprocattr(struct task_struct *p, char *name, if (p != current) return -EPERM; - if (!capable(CAP_MAC_ADMIN)) + if (!smack_privileged(CAP_MAC_ADMIN)) return -EPERM; if (value == NULL || size == 0 || size >= SMK_LONGLABEL) @@ -2780,7 +2781,7 @@ static int smack_unix_stream_connect(struct sock *sock, smk_ad_setfield_u_net_sk(&ad, other); #endif - if (!capable(CAP_MAC_OVERRIDE)) + if (!smack_privileged(CAP_MAC_OVERRIDE)) rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad); /* @@ -2816,7 +2817,7 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other) smk_ad_setfield_u_net_sk(&ad, other->sk); #endif - if (!capable(CAP_MAC_OVERRIDE)) + if (!smack_privileged(CAP_MAC_OVERRIDE)) rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad); return rc; diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 3686db7e2c6b..21529658662b 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -595,13 +595,12 @@ static int smk_open_load(struct inode *inode, struct file *file) static ssize_t smk_write_load(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { - /* * Must have privilege. * No partial writes. * Enough data must be present. */ - if (!capable(CAP_MAC_ADMIN)) + if (!smack_privileged(CAP_MAC_ADMIN)) return -EPERM; return smk_write_rules_list(file, buf, count, ppos, NULL, NULL, @@ -787,7 +786,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf, * No partial writes. * Enough data must be present. */ - if (!capable(CAP_MAC_ADMIN)) + if (!smack_privileged(CAP_MAC_ADMIN)) return -EPERM; if (*ppos != 0) return -EINVAL; @@ -1090,7 +1089,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf, * "