diff options
Diffstat (limited to 'security/smack/smack_lsm.c')
| -rw-r--r-- | security/smack/smack_lsm.c | 287 |
1 files changed, 244 insertions, 43 deletions
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 533bf32..23c7a6d 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -33,6 +33,7 @@ #include <net/cipso_ipv4.h> #include <linux/audit.h> #include <linux/magic.h> +#include <linux/dcache.h> #include "smack.h" #define task_security(task) (task_cred_xxx((task), security)) @@ -84,6 +85,56 @@ struct inode_smack *new_inode_smack(char *smack) return isp; } +/** + * new_task_smack - allocate a task security blob + * @smack: a pointer to the Smack label to use in the blob + * + * Returns the new blob or NULL if there's no memory available + */ +static struct task_smack *new_task_smack(char *task, char *forked, gfp_t gfp) +{ + struct task_smack *tsp; + + tsp = kzalloc(sizeof(struct task_smack), gfp); + if (tsp == NULL) + return NULL; + + tsp->smk_task = task; + tsp->smk_forked = forked; + INIT_LIST_HEAD(&tsp->smk_rules); + mutex_init(&tsp->smk_rules_lock); + + return tsp; +} + +/** + * smk_copy_rules - copy a rule set + * @nhead - new rules header pointer + * @ohead - old rules header pointer + * + * Returns 0 on success, -ENOMEM on error + */ +static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead, + gfp_t gfp) +{ + struct smack_rule *nrp; + struct smack_rule *orp; + int rc = 0; + + INIT_LIST_HEAD(nhead); + + list_for_each_entry_rcu(orp, ohead, list) { + nrp = kzalloc(sizeof(struct smack_rule), gfp); + if (nrp == NULL) { + rc = -ENOMEM; + break; + } + *nrp = *orp; + list_add_rcu(&nrp->list, nhead); + } + return rc; +} + /* * LSM hooks. * We he, that is fun! @@ -102,23 +153,17 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode) { int rc; struct smk_audit_info ad; - char *sp, *tsp; + char *tsp; rc = cap_ptrace_access_check(ctp, mode); if (rc != 0) return rc; - sp = smk_of_current(); tsp = smk_of_task(task_security(ctp)); smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); smk_ad_setfield_u_tsk(&ad, ctp); - /* we won't log here, because rc can be overriden */ - rc = smk_access(sp, tsp, MAY_READWRITE, NULL); - if (rc != 0 && capable(CAP_MAC_OVERRIDE)) - rc = 0; - - smack_log(sp, tsp, MAY_READWRITE, rc, &ad); + rc = smk_curacc(tsp, MAY_READWRITE, &ad); return rc; } @@ -134,23 +179,17 @@ static int smack_ptrace_traceme(struct task_struct *ptp) { int rc; struct smk_audit_info ad; - char *sp, *tsp; + char *tsp; rc = cap_ptrace_traceme(ptp); if (rc != 0) return rc; + tsp = smk_of_task(task_security(ptp)); smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); smk_ad_setfield_u_tsk(&ad, ptp); - sp = smk_of_current(); - tsp = smk_of_task(task_security(ptp)); - /* we won't log here, because rc can be overriden */ - rc = smk_access(tsp, sp, MAY_READWRITE, NULL); - if (rc != 0 && has_capability(ptp, CAP_MAC_OVERRIDE)) - rc = 0; - - smack_log(tsp, sp, MAY_READWRITE, rc, &ad); + rc = smk_curacc(tsp, MAY_READWRITE, &ad); return rc; } @@ -463,6 +502,7 @@ static void smack_inode_free_security(struct inode *inode) * smack_inode_init_security - copy out the smack from an inode * @inode: the inode * @dir: unused + * @qstr: unused * @name: where to put the attribute name * @value: where to put the attribute value * @len: where to put the length of the attribute @@ -470,11 +510,12 @@ static void smack_inode_free_security(struct inode *inode) * Returns 0 if it all works out, -ENOMEM if there's no memory */ static int smack_inode_init_security(struct inode *inode, struct inode *dir, - char **name, void **value, size_t *len) + const struct qstr *qstr, char **name, + void **value, size_t *len) { char *isp = smk_of_inode(inode); char *dsp = smk_of_inode(dir); - u32 may; + int may; if (name) { *name = kstrdup(XATTR_SMACK_SUFFIX, GFP_KERNEL); @@ -483,14 +524,17 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, } if (value) { - may = smk_access_entry(smk_of_current(), dsp); + rcu_read_lock(); + may = smk_access_entry(smk_of_current(), dsp, &smack_rule_list); + rcu_read_unlock(); /* * If the access rule allows transmutation and * the directory requests transmutation then * by all means transmute. */ - if (((may & MAY_TRANSMUTE) != 0) && smk_inode_transmutable(dir)) + if (may > 0 && ((may & MAY_TRANSMUTE) != 0) && + smk_inode_transmutable(dir)) isp = dsp; *value = kstrdup(isp, GFP_KERNEL); @@ -716,7 +760,8 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name, if (strcmp(name, XATTR_NAME_SMACK) == 0 || strcmp(name, XATTR_NAME_SMACKIPIN) == 0 || strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 || - strcmp(name, XATTR_NAME_SMACKEXEC) == 0) { + strcmp(name, XATTR_NAME_SMACKEXEC) == 0 || + strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { if (!capable(CAP_MAC_ADMIN)) rc = -EPERM; /* @@ -773,6 +818,12 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name, isp->smk_task = nsp; else isp->smk_task = smack_known_invalid.smk_known; + } else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { + nsp = smk_import(value, size); + if (nsp != NULL) + isp->smk_mmap = nsp; + else + isp->smk_mmap = smack_known_invalid.smk_known; } else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) isp->smk_flags |= SMK_INODE_TRANSMUTE; @@ -815,7 +866,8 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name) strcmp(name, XATTR_NAME_SMACKIPIN) == 0 || strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 || strcmp(name, XATTR_NAME_SMACKEXEC) == 0 || - strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) { + strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 || + strcmp(name, XATTR_NAME_SMACKMMAP)) { if (!capable(CAP_MAC_ADMIN)) rc = -EPERM; } else @@ -829,6 +881,7 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name) if (rc == 0) { isp = dentry->d_inode->i_security; isp->smk_task = NULL; + isp->smk_mmap = NULL; } return rc; @@ -1060,6 +1113,126 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd, } /** + * smack_file_mmap : + * Check permissions for a mmap operation. The @file may be NULL, e.g. + * if mapping anonymous memory. + * @file contains the file structure for file to map (may be NULL). + * @reqprot contains the protection requested by the application. + * @prot contains the protection that will be applied by the kernel. + * @flags contains the operational flags. + * Return 0 if permission is granted. + */ +static int smack_file_mmap(struct file *file, + unsigned long reqprot, unsigned long prot, + unsigned long flags, unsigned long addr, + unsigned long addr_only) +{ + struct smack_rule *srp; + struct task_smack *tsp; + char *sp; + char *msmack; + char *osmack; + struct inode_smack *isp; + struct dentry *dp; + int may; + int mmay; + int tmay; + int rc; + + /* do DAC check on address space usage */ + rc = cap_file_mmap(file, reqprot, prot, flags, addr, addr_only); + if (rc || addr_only) + return rc; + + if (file == NULL || file->f_dentry == NULL) + return 0; + + dp = file->f_dentry; + + if (dp->d_inode == NULL) + return 0; + + isp = dp->d_inode->i_security; + if (isp->smk_mmap == NULL) + return 0; + msmack = isp->smk_mmap; + + tsp = current_security(); + sp = smk_of_current(); + rc = 0; + + rcu_read_lock(); + /* + * For each Smack rule associated with the subject + * label verify that the SMACK64MMAP also has access + * to that rule's object label. + * + * Because neither of the labels comes + * from the networking code it is sufficient + * to compare pointers. + */ + list_for_each_entry_rcu(srp, &smack_rule_list, list) { + if (srp->smk_subject != sp) + continue; + + osmack = srp->smk_object; + /* + * Matching labels always allows access. + */ + if (msmack == osmack) + continue; + /* + * If there is a matching local rule take + * that into account as well. + */ + may = smk_access_entry(srp->smk_subject, osmack, + &tsp->smk_rules); + if (may == -ENOENT) + may = srp->smk_access; + else + may &= srp->smk_access; + /* + * If may is zero the SMACK64MMAP subject can't + * possibly have less access. + */ + if (may == 0) + continue; + + /* + * Fetch the global list entry. + * If there isn't one a SMACK64MMAP subject + * can't have as much access as current. + */ + mmay = smk_access_entry(msmack, osmack, &smack_rule_list); + if (mmay == -ENOENT) { + rc = -EACCES; + break; + } + /* + * If there is a local entry it modifies the + * potential access, too. + */ + tmay = smk_access_entry(msmack, osmack, &tsp->smk_rules); + if (tmay != -ENOENT) + mmay &= tmay; + + /* + * If there is any access available to current that is + * not available to a SMACK64MMAP subject + * deny access. + */ + if ((may | mmay) != mmay) { + rc = -EACCES; + break; + } + } + + rcu_read_unlock(); + + return rc; +} + +/** * smack_file_set_fowner - set the file security blob value * @file: object in question * @@ -1095,6 +1268,7 @@ static int smack_file_send_sigiotask(struct task_struct *tsk, * struct fown_struct is never outside the context of a struct file */ file = container_of(fown, struct file, f_owner); + /* we don't log here as rc can be overriden */ rc = smk_access(file->f_security, tsp, MAY_WRITE, NULL); if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE)) @@ -1145,9 +1319,14 @@ static int smack_file_receive(struct file *file) */ static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp) { - cred->security = kzalloc(sizeof(struct task_smack), gfp); - if (cred->security == NULL) + struct task_smack *tsp; + + tsp = new_task_smack(NULL, NULL, gfp); + if (tsp == NULL) return -ENOMEM; + + cred->security = tsp; + return 0; } @@ -1156,13 +1335,24 @@ static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp) * smack_cred_free - "free" task-level security credentials * @cred: the credentials in question * - * Smack isn't using copies of blobs. Everyone - * points to an immutable list. The blobs never go away. - * There is no leak here. */ static void smack_cred_free(struct cred *cred) { - kfree(cred->security); + struct task_smack *tsp = cred->security; + struct smack_rule *rp; + struct list_head *l; + struct list_head *n; + + if (tsp == NULL) + return; + cred->security = NULL; + + list_for_each_safe(l, n, &tsp->smk_rules) { + rp = list_entry(l, struct smack_rule, list); + list_del(&rp->list); + kfree(rp); + } + kfree(tsp); } /** @@ -1178,13 +1368,16 @@ static int smack_cred_prepare(struct cred *new, const struct cred *old, { struct task_smack *old_tsp = old->security; struct task_smack *new_tsp; + int rc; - new_tsp = kzalloc(sizeof(struct task_smack), gfp); + new_tsp = new_task_smack(old_tsp->smk_task, old_tsp->smk_task, gfp); if (new_tsp == NULL) return -ENOMEM; - new_tsp->smk_task = old_tsp->smk_task; - new_tsp->smk_forked = old_tsp->smk_task; + rc = smk_copy_rules(&new_tsp->smk_rules, &old_tsp->smk_rules, gfp); + if (rc != 0) + return rc; + new->security = new_tsp; return 0; } @@ -1203,6 +1396,11 @@ static void smack_cred_transfer(struct cred *new, const struct cred *old) new_tsp->smk_task = old_tsp->smk_task; new_tsp->smk_forked = old_tsp->smk_task; + mutex_init(&new_tsp->smk_rules_lock); + INIT_LIST_HEAD(&new_tsp->smk_rules); + + + /* cbs copy rule list */ } /** @@ -2419,6 +2617,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) } } isp->smk_task = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); + isp->smk_mmap = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp); dput(dp); break; @@ -2478,6 +2677,7 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value) static int smack_setprocattr(struct task_struct *p, char *name, void *value, size_t size) { + int rc; struct task_smack *tsp; struct task_smack *oldtsp; struct cred *new; @@ -2513,13 +2713,16 @@ static int smack_setprocattr(struct task_struct *p, char *name, new = prepare_creds(); if (new == NULL) return -ENOMEM; - tsp = kzalloc(sizeof(struct task_smack), GFP_KERNEL); + + tsp = new_task_smack(newsmack, oldtsp->smk_forked, GFP_KERNEL); if (tsp == NULL) { kfree(new); return -ENOMEM; } - tsp->smk_task = newsmack; - tsp->smk_forked = oldtsp->smk_forked; + rc = smk_copy_rules(&tsp->smk_rules, &oldtsp->smk_rules, GFP_KERNEL); + if (rc != 0) + return rc; + new->security = tsp; commit_creds(new); return size; @@ -3221,6 +3424,7 @@ struct security_operations smack_ops = { .file_ioctl = smack_file_ioctl, .file_lock = smack_file_lock, .file_fcntl = smack_file_fcntl, + .file_mmap = smack_file_mmap, .file_set_fowner = smack_file_set_fowner, .file_send_sigiotask = smack_file_send_sigiotask, .file_receive = smack_file_receive, @@ -3334,23 +3538,20 @@ static __init int smack_init(void) struct cred *cred; struct task_smack *tsp; - tsp = kzalloc(sizeof(struct task_smack), GFP_KERNEL); + if (!security_module_enable(&smack_ops)) + return 0; + + tsp = new_task_smack(smack_known_floor.smk_known, + smack_known_floor.smk_known, GFP_KERNEL); if (tsp == NULL) return -ENOMEM; - if (!security_module_enable(&smack_ops)) { - kfree(tsp); - return 0; - } - printk(KERN_INFO "Smack: Initializing.\n"); /* * Set the security state for the initial task. */ cred = (struct cred *) current->cred; - tsp->smk_forked = smack_known_floor.smk_known; - tsp->smk_task = smack_known_floor.smk_known; cred->security = tsp; /* initialize the smack_know_list */ |