Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753001Ab0KYLu2 (ORCPT ); Thu, 25 Nov 2010 06:50:28 -0500 Received: from smtp.nokia.com ([147.243.1.48]:48027 "EHLO mgw-sa02.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752947Ab0KYLu0 (ORCPT ); Thu, 25 Nov 2010 06:50:26 -0500 Message-ID: <4CEE4D6E.4030204@nokia.com> Date: Thu, 25 Nov 2010 13:50:06 +0200 From: Jarkko Sakkinen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.12) Gecko/20101027 Lightning/1.0b2 Thunderbird/3.1.6 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, Casey Schaufler CC: "Sakkinen Jarkko.2 (EXT-Tieto/Tampere)" Subject: [PATCH] Smack: label for task objects (retry 2) Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 20320 Lines: 657 This patch adds a new security attribute to Smack called SMACK64EXEC. It defines label that is used while task is running. Exception: in smack_task_wait() child task is checked for write access to parent task using label inherited from the task that forked it. Fixed issues from previous submit: - SMACK64EXEC was not read when SMACK64 was not set. - inode security blob was not updated after setting SMACK64EXEC - inode security blob was not updated when removing SMACK64EXEC Thanks to Casey pointing out second and third issue and helping out in testing. Signed-off-by: Jarkko Sakkinen --- include/linux/xattr.h | 2 + security/smack/smack.h | 30 +++++++ security/smack/smack_access.c | 4 +- security/smack/smack_lsm.c | 192 ++++++++++++++++++++++++++++++----------- security/smack/smackfs.c | 4 +- 5 files changed, 178 insertions(+), 54 deletions(-) diff --git a/include/linux/xattr.h b/include/linux/xattr.h index f1e5bde..351c790 100644 --- a/include/linux/xattr.h +++ b/include/linux/xattr.h @@ -40,9 +40,11 @@ #define XATTR_SMACK_SUFFIX "SMACK64" #define XATTR_SMACK_IPIN "SMACK64IPIN" #define XATTR_SMACK_IPOUT "SMACK64IPOUT" +#define XATTR_SMACK_EXEC "SMACK64EXEC" #define XATTR_NAME_SMACK XATTR_SECURITY_PREFIX XATTR_SMACK_SUFFIX #define XATTR_NAME_SMACKIPIN XATTR_SECURITY_PREFIX XATTR_SMACK_IPIN #define XATTR_NAME_SMACKIPOUT XATTR_SECURITY_PREFIX XATTR_SMACK_IPOUT +#define XATTR_NAME_SMACKEXEC XATTR_SECURITY_PREFIX XATTR_SMACK_EXEC #define XATTR_CAPS_SUFFIX "capability" #define XATTR_NAME_CAPS XATTR_SECURITY_PREFIX XATTR_CAPS_SUFFIX diff --git a/security/smack/smack.h b/security/smack/smack.h index 43ae747..a2e2cdf 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -51,10 +51,16 @@ struct socket_smack { */ struct inode_smack { char *smk_inode; /* label of the fso */ + char *smk_task; /* label of the task */ struct mutex smk_lock; /* initialization lock */ int smk_flags; /* smack inode flags */ }; +struct task_smack { + char *smk_task; /* label used for access control */ + char *smk_forked; /* label when forked */ +}; + #define SMK_INODE_INSTANT 0x01 /* inode is instantiated */ /* @@ -243,6 +249,30 @@ static inline char *smk_of_inode(const struct inode *isp) } /* + * Present a pointer to the smack label in an task blob. + */ +static inline char *smk_of_task(const struct task_smack *tsp) +{ + return tsp->smk_task; +} + +/* + * Present a pointer to the forked smack label in an task blob. + */ +static inline char *smk_of_forked(const struct task_smack *tsp) +{ + return tsp->smk_forked; +} + +/* + * Present a pointer to the smack label in the curren task blob. + */ +static inline char *smk_of_current(void) +{ + return smk_of_task(current_security()); +} + +/* * logging functions */ #define SMACK_AUDIT_DENIED 0x1 diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c index f4fac64..42becbc 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -185,7 +185,7 @@ out_audit: int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) { int rc; - char *sp = current_security(); + char *sp = smk_of_current(); rc = smk_access(sp, obj_label, mode, NULL); if (rc == 0) @@ -196,7 +196,7 @@ int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) * only one that gets privilege and current does not * have that label. */ - if (smack_onlycap != NULL && smack_onlycap != current->cred->security) + if (smack_onlycap != NULL && smack_onlycap != sp) goto out_audit; if (capable(CAP_MAC_OVERRIDE)) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 04a98c3..7e19afe 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -43,7 +43,7 @@ * Returns a pointer to the master list entry for the Smack label * or NULL if there was no label to fetch. */ -static char *smk_fetch(struct inode *ip, struct dentry *dp) +static char *smk_fetch(const char *name, struct inode *ip, struct dentry *dp) { int rc; char in[SMK_LABELLEN]; @@ -51,7 +51,7 @@ static char *smk_fetch(struct inode *ip, struct dentry *dp) if (ip->i_op->getxattr == NULL) return NULL; - rc = ip->i_op->getxattr(dp, XATTR_NAME_SMACK, in, SMK_LABELLEN); + rc = ip->i_op->getxattr(dp, name, in, SMK_LABELLEN); if (rc < 0) return NULL; @@ -103,8 +103,8 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode) if (rc != 0) return rc; - sp = current_security(); - tsp = task_security(ctp); + 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); @@ -138,8 +138,8 @@ static int smack_ptrace_traceme(struct task_struct *ptp) smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); smk_ad_setfield_u_tsk(&ad, ptp); - sp = current_security(); - tsp = task_security(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)) @@ -160,7 +160,7 @@ static int smack_ptrace_traceme(struct task_struct *ptp) static int smack_syslog(int typefrom_file) { int rc = 0; - char *sp = current_security(); + char *sp = smk_of_current(); if (capable(CAP_MAC_OVERRIDE)) return 0; @@ -391,6 +391,40 @@ static int smack_sb_umount(struct vfsmount *mnt, int flags) } /* + * BPRM hooks + */ + +static int smack_bprm_set_creds(struct linux_binprm *bprm) +{ + struct task_smack *tsp = bprm->cred->security; + struct inode_smack *isp; + struct dentry *dp; + int rc; + + rc = cap_bprm_set_creds(bprm); + if (rc != 0) + return rc; + + if (bprm->cred_prepared) + return 0; + + if (bprm->file == NULL || bprm->file->f_dentry == NULL) + return 0; + + dp = bprm->file->f_dentry; + + if (dp->d_inode == NULL) + return 0; + + isp = dp->d_inode->i_security; + + if (isp->smk_task != NULL) + tsp->smk_task = isp->smk_task; + + return 0; +} + +/* * Inode hooks */ @@ -402,7 +436,7 @@ static int smack_sb_umount(struct vfsmount *mnt, int flags) */ static int smack_inode_alloc_security(struct inode *inode) { - inode->i_security = new_inode_smack(current_security()); + inode->i_security = new_inode_smack(smk_of_current()); if (inode->i_security == NULL) return -ENOMEM; return 0; @@ -664,7 +698,8 @@ 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_SMACKIPOUT) == 0 || + strcmp(name, XATTR_NAME_SMACKEXEC) == 0) { if (!capable(CAP_MAC_ADMIN)) rc = -EPERM; /* @@ -704,9 +739,10 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name, char *nsp; /* - * Not SMACK + * Not SMACK or SMACKEXEC */ - if (strcmp(name, XATTR_NAME_SMACK)) + if (strcmp(name, XATTR_NAME_SMACK) && + strcmp(name, XATTR_NAME_SMACKEXEC)) return; isp = dentry->d_inode->i_security; @@ -716,10 +752,18 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name, * assignment. */ nsp = smk_import(value, size); - if (nsp != NULL) - isp->smk_inode = nsp; - else - isp->smk_inode = smack_known_invalid.smk_known; + + if (strcmp(name, XATTR_NAME_SMACK) == 0) { + if (nsp != NULL) + isp->smk_inode = nsp; + else + isp->smk_inode = smack_known_invalid.smk_known; + } else { + if (nsp != NULL) + isp->smk_task = nsp; + else + isp->smk_task = smack_known_invalid.smk_known; + } return; } @@ -752,12 +796,14 @@ static int smack_inode_getxattr(struct dentry *dentry, const char *name) */ static int smack_inode_removexattr(struct dentry *dentry, const char *name) { + struct inode_smack *isp; struct smk_audit_info ad; int rc = 0; if (strcmp(name, XATTR_NAME_SMACK) == 0 || strcmp(name, XATTR_NAME_SMACKIPIN) == 0 || - strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) { + strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 || + strcmp(name, XATTR_NAME_SMACKEXEC) == 0) { if (!capable(CAP_MAC_ADMIN)) rc = -EPERM; } else @@ -768,6 +814,11 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name) if (rc == 0) rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad); + if (rc == 0) { + isp = dentry->d_inode->i_security; + isp->smk_task = NULL; + } + return rc; } @@ -895,7 +946,7 @@ static int smack_file_permission(struct file *file, int mask) */ static int smack_file_alloc_security(struct file *file) { - file->f_security = current_security(); + file->f_security = smk_of_current(); return 0; } @@ -1005,7 +1056,7 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd, */ static int smack_file_set_fowner(struct file *file) { - file->f_security = current_security(); + file->f_security = smk_of_current(); return 0; } @@ -1025,7 +1076,7 @@ static int smack_file_send_sigiotask(struct task_struct *tsk, { struct file *file; int rc; - char *tsp = tsk->cred->security; + char *tsp = smk_of_task(tsk->cred->security); struct smk_audit_info ad; /* @@ -1082,7 +1133,9 @@ static int smack_file_receive(struct file *file) */ static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp) { - cred->security = NULL; + cred->security = kzalloc(sizeof(struct task_smack), gfp); + if (cred->security == NULL) + return -ENOMEM; return 0; } @@ -1097,7 +1150,7 @@ static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp) */ static void smack_cred_free(struct cred *cred) { - cred->security = NULL; + kfree(cred->security); } /** @@ -1111,7 +1164,16 @@ static void smack_cred_free(struct cred *cred) static int smack_cred_prepare(struct cred *new, const struct cred *old, gfp_t gfp) { - new->security = old->security; + struct task_smack *old_tsp = old->security; + struct task_smack *new_tsp; + + new_tsp = kzalloc(sizeof(struct task_smack), gfp); + if (new_tsp == NULL) + return -ENOMEM; + + new_tsp->smk_task = old_tsp->smk_task; + new_tsp->smk_forked = old_tsp->smk_task; + new->security = new_tsp; return 0; } @@ -1124,7 +1186,11 @@ static int smack_cred_prepare(struct cred *new, const struct cred *old, */ static void smack_cred_transfer(struct cred *new, const struct cred *old) { - new->security = old->security; + struct task_smack *old_tsp = old->security; + struct task_smack *new_tsp = new->security; + + new_tsp->smk_task = old_tsp->smk_task; + new_tsp->smk_forked = old_tsp->smk_task; } /** @@ -1136,12 +1202,13 @@ static void smack_cred_transfer(struct cred *new, const struct cred *old) */ static int smack_kernel_act_as(struct cred *new, u32 secid) { + struct task_smack *new_tsp = new->security; char *smack = smack_from_secid(secid); if (smack == NULL) return -EINVAL; - new->security = smack; + new_tsp->smk_task = smack; return 0; } @@ -1157,8 +1224,10 @@ static int smack_kernel_create_files_as(struct cred *new, struct inode *inode) { struct inode_smack *isp = inode->i_security; + struct task_smack *tsp = new->security; - new->security = isp->smk_inode; + tsp->smk_forked = isp->smk_inode; + tsp->smk_task = isp->smk_inode; return 0; } @@ -1175,7 +1244,7 @@ static int smk_curacc_on_task(struct task_struct *p, int access) smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); smk_ad_setfield_u_tsk(&ad, p); - return smk_curacc(task_security(p), access, &ad); + return smk_curacc(smk_of_task(task_security(p)), access, &ad); } /** @@ -1221,7 +1290,7 @@ static int smack_task_getsid(struct task_struct *p) */ static void smack_task_getsecid(struct task_struct *p, u32 *secid) { - *secid = smack_to_secid(task_security(p)); + *secid = smack_to_secid(smk_of_task(task_security(p))); } /** @@ -1333,14 +1402,15 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info, * can write the receiver. */ if (secid == 0) - return smk_curacc(task_security(p), MAY_WRITE, &ad); + return smk_curacc(smk_of_task(task_security(p)), MAY_WRITE, + &ad); /* * If the secid isn't 0 we're dealing with some USB IO * specific behavior. This is not clean. For one thing * we can't take privilege into account. */ - return smk_access(smack_from_secid(secid), task_security(p), - MAY_WRITE, &ad); + return smk_access(smack_from_secid(secid), + smk_of_task(task_security(p)), MAY_WRITE, &ad); } /** @@ -1352,12 +1422,12 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info, static int smack_task_wait(struct task_struct *p) { struct smk_audit_info ad; - char *sp = current_security(); - char *tsp = task_security(p); + char *sp = smk_of_current(); + char *tsp = smk_of_forked(task_security(p)); int rc; /* we don't log here, we can be overriden */ - rc = smk_access(sp, tsp, MAY_WRITE, NULL); + rc = smk_access(tsp, sp, MAY_WRITE, NULL); if (rc == 0) goto out_log; @@ -1378,7 +1448,7 @@ static int smack_task_wait(struct task_struct *p) out_log: smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); smk_ad_setfield_u_tsk(&ad, p); - smack_log(sp, tsp, MAY_WRITE, rc, &ad); + smack_log(tsp, sp, MAY_WRITE, rc, &ad); return rc; } @@ -1392,7 +1462,7 @@ static int smack_task_wait(struct task_struct *p) static void smack_task_to_inode(struct task_struct *p, struct inode *inode) { struct inode_smack *isp = inode->i_security; - isp->smk_inode = task_security(p); + isp->smk_inode = smk_of_task(task_security(p)); } /* @@ -1411,7 +1481,7 @@ static void smack_task_to_inode(struct task_struct *p, struct inode *inode) */ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags) { - char *csp = current_security(); + char *csp = smk_of_current(); struct socket_smack *ssp; ssp = kzalloc(sizeof(struct socket_smack), gfp_flags); @@ -1752,7 +1822,7 @@ static int smack_flags_to_may(int flags) */ static int smack_msg_msg_alloc_security(struct msg_msg *msg) { - msg->security = current_security(); + msg->security = smk_of_current(); return 0; } @@ -1788,7 +1858,7 @@ static int smack_shm_alloc_security(struct shmid_kernel *shp) { struct kern_ipc_perm *isp = &shp->shm_perm; - isp->security = current_security(); + isp->security = smk_of_current(); return 0; } @@ -1911,7 +1981,7 @@ static int smack_sem_alloc_security(struct sem_array *sma) { struct kern_ipc_perm *isp = &sma->sem_perm; - isp->security = current_security(); + isp->security = smk_of_current(); return 0; } @@ -2029,7 +2099,7 @@ static int smack_msg_queue_alloc_security(struct msg_queue *msq) { struct kern_ipc_perm *kisp = &msq->q_perm; - kisp->security = current_security(); + kisp->security = smk_of_current(); return 0; } @@ -2201,7 +2271,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) struct super_block *sbp; struct superblock_smack *sbsp; struct inode_smack *isp; - char *csp = current_security(); + char *csp = smk_of_current(); char *fetched; char *final; struct dentry *dp; @@ -2321,9 +2391,12 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) * Get the dentry for xattr. */ dp = dget(opt_dentry); - fetched = smk_fetch(inode, dp); + fetched = smk_fetch(XATTR_NAME_SMACK, inode, dp); if (fetched != NULL) final = fetched; + isp->smk_task = smk_fetch(XATTR_NAME_SMACKEXEC, inode, + dp); + dput(dp); break; } @@ -2358,7 +2431,7 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value) if (strcmp(name, "current") != 0) return -EINVAL; - cp = kstrdup(task_security(p), GFP_KERNEL); + cp = kstrdup(smk_of_task(task_security(p)), GFP_KERNEL); if (cp == NULL) return -ENOMEM; @@ -2382,6 +2455,7 @@ 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) { + struct task_smack *tsp; struct cred *new; char *newsmack; @@ -2414,7 +2488,13 @@ static int smack_setprocattr(struct task_struct *p, char *name, new = prepare_creds(); if (new == NULL) return -ENOMEM; - new->security = newsmack; + tsp = kzalloc(sizeof(struct task_smack), GFP_KERNEL); + if (tsp == NULL) { + kfree(new); + return -ENOMEM; + } + tsp->smk_task = newsmack; + new->security = tsp; commit_creds(new); return size; } @@ -2715,7 +2795,7 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent) return; ssp = sk->sk_security; - ssp->smk_in = ssp->smk_out = current_security(); + ssp->smk_in = ssp->smk_out = smk_of_current(); /* cssp->smk_packet is already set in smack_inet_csk_clone() */ } @@ -2836,7 +2916,7 @@ static void smack_inet_csk_clone(struct sock *sk, static int smack_key_alloc(struct key *key, const struct cred *cred, unsigned long flags) { - key->security = cred->security; + key->security = smk_of_task(cred->security); return 0; } @@ -2865,6 +2945,7 @@ static int smack_key_permission(key_ref_t key_ref, { struct key *keyp; struct smk_audit_info ad; + char *tsp = smk_of_task(cred->security); keyp = key_ref_to_ptr(key_ref); if (keyp == NULL) @@ -2878,14 +2959,14 @@ static int smack_key_permission(key_ref_t key_ref, /* * This should not occur */ - if (cred->security == NULL) + if (tsp == NULL) return -EACCES; #ifdef CONFIG_AUDIT smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY); ad.a.u.key_struct.key = keyp->serial; ad.a.u.key_struct.key_desc = keyp->description; #endif - return smk_access(cred->security, keyp->security, + return smk_access(tsp, keyp->security, MAY_READWRITE, &ad); } #endif /* CONFIG_KEYS */ @@ -3087,6 +3168,8 @@ struct security_operations smack_ops = { .sb_mount = smack_sb_mount, .sb_umount = smack_sb_umount, + .bprm_set_creds = smack_bprm_set_creds, + .inode_alloc_security = smack_inode_alloc_security, .inode_free_security = smack_inode_free_security, .inode_init_security = smack_inode_init_security, @@ -3223,9 +3306,16 @@ static __init void init_smack_know_list(void) static __init int smack_init(void) { struct cred *cred; + struct task_smack *tsp; - if (!security_module_enable(&smack_ops)) + tsp = kzalloc(sizeof(struct task_smack), GFP_KERNEL); + if (tsp == NULL) + return -ENOMEM; + + if (!security_module_enable(&smack_ops)) { + kfree(tsp); return 0; + } printk(KERN_INFO "Smack: Initializing.\n"); @@ -3233,7 +3323,9 @@ static __init int smack_init(void) * Set the security state for the initial task. */ cred = (struct cred *) current->cred; - cred->security = &smack_known_floor.smk_known; + tsp->smk_forked = smack_known_floor.smk_known; + tsp->smk_task = smack_known_floor.smk_known; + cred->security = tsp; /* initialize the smack_know_list */ init_smack_know_list(); diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index dc1fd62..01a0be9 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -121,7 +121,7 @@ static void smk_netlabel_audit_set(struct netlbl_audit *nap) { nap->loginuid = audit_get_loginuid(current); nap->sessionid = audit_get_sessionid(current); - nap->secid = smack_to_secid(current_security()); + nap->secid = smack_to_secid(smk_of_current()); } /* @@ -1160,7 +1160,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { char in[SMK_LABELLEN]; - char *sp = current->cred->security; + char *sp = smk_of_task(current->cred->security); if (!capable(CAP_MAC_ADMIN)) return -EPERM; -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/