diff options
Diffstat (limited to 'security/smack')
| -rw-r--r-- | security/smack/smack.h | 33 | ||||
| -rw-r--r-- | security/smack/smack_access.c | 48 | ||||
| -rw-r--r-- | security/smack/smack_lsm.c | 403 | ||||
| -rw-r--r-- | security/smack/smackfs.c | 220 |
4 files changed, 520 insertions, 184 deletions
diff --git a/security/smack/smack.h b/security/smack/smack.h index 076b8e8a51a..020307ef097 100644 --- a/security/smack/smack.h +++ b/security/smack/smack.h @@ -80,8 +80,8 @@ struct superblock_smack { struct socket_smack { struct smack_known *smk_out; /* outbound label */ - char *smk_in; /* inbound label */ - char *smk_packet; /* TCP peer label */ + struct smack_known *smk_in; /* inbound label */ + struct smack_known *smk_packet; /* TCP peer label */ }; /* @@ -133,7 +133,7 @@ struct smk_port_label { struct list_head list; struct sock *smk_sock; /* socket initialized on */ unsigned short smk_port; /* the port number */ - char *smk_in; /* incoming label */ + struct smack_known *smk_in; /* inbound label */ struct smack_known *smk_out; /* outgoing label */ }; @@ -177,9 +177,21 @@ struct smk_port_label { #define SMACK_CIPSO_MAXCATNUM 184 /* 23 * 8 */ /* - * Flag for transmute access + * Ptrace rules */ -#define MAY_TRANSMUTE 64 +#define SMACK_PTRACE_DEFAULT 0 +#define SMACK_PTRACE_EXACT 1 +#define SMACK_PTRACE_DRACONIAN 2 +#define SMACK_PTRACE_MAX SMACK_PTRACE_DRACONIAN + +/* + * Flags for untraditional access modes. + * It shouldn't be necessary to avoid conflicts with definitions + * in fs.h, but do so anyway. + */ +#define MAY_TRANSMUTE 0x00001000 /* Controls directory labeling */ +#define MAY_LOCK 0x00002000 /* Locks should be writes, but ... */ + /* * Just to make the common cases easier to deal with */ @@ -188,9 +200,9 @@ struct smk_port_label { #define MAY_NOT 0 /* - * Number of access types used by Smack (rwxat) + * Number of access types used by Smack (rwxatl) */ -#define SMK_NUM_ACCESS_TYPE 5 +#define SMK_NUM_ACCESS_TYPE 6 /* SMACK data */ struct smack_audit_data { @@ -221,6 +233,7 @@ struct inode_smack *new_inode_smack(char *); */ int smk_access_entry(char *, char *, struct list_head *); int smk_access(struct smack_known *, char *, int, struct smk_audit_info *); +int smk_tskacc(struct task_smack *, char *, u32, struct smk_audit_info *); int smk_curacc(char *, u32, struct smk_audit_info *); struct smack_known *smack_from_secid(const u32); char *smk_parse_smack(const char *string, int len); @@ -237,8 +250,10 @@ 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 int smack_ptrace_rule; extern struct smack_known smack_known_floor; extern struct smack_known smack_known_hat; @@ -308,7 +323,7 @@ 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_access.c b/security/smack/smack_access.c index b3b59b1e93d..c062e9467b6 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -84,6 +84,8 @@ int log_policy = SMACK_AUDIT_DENIED; * * Do the object check first because that is more * likely to differ. + * + * Allowing write access implies allowing locking. */ int smk_access_entry(char *subject_label, char *object_label, struct list_head *rule_list) @@ -99,6 +101,11 @@ int smk_access_entry(char *subject_label, char *object_label, } } + /* + * MAY_WRITE implies MAY_LOCK. + */ + if ((may & MAY_WRITE) == MAY_WRITE) + may |= MAY_LOCK; return may; } @@ -185,20 +192,21 @@ out_audit: } /** - * smk_curacc - determine if current has a specific access to an object + * smk_tskacc - determine if a task has a specific access to an object + * @tsp: a pointer to the subject task * @obj_label: a pointer to the object's Smack label * @mode: the access requested, in "MAY" format * @a : common audit data * - * This function checks the current subject label/object label pair + * This function checks the subject task's label/object label pair * in the access rule list and returns 0 if the access is permitted, - * non zero otherwise. It allows that current may have the capability + * non zero otherwise. It allows that the task may have the capability * to override the rules. */ -int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) +int smk_tskacc(struct task_smack *subject, char *obj_label, + u32 mode, struct smk_audit_info *a) { - struct task_smack *tsp = current_security(); - struct smack_known *skp = smk_of_task(tsp); + struct smack_known *skp = smk_of_task(subject); int may; int rc; @@ -212,7 +220,7 @@ int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) * it can further restrict access. */ may = smk_access_entry(skp->smk_known, obj_label, - &tsp->smk_rules); + &subject->smk_rules); if (may < 0) goto out_audit; if ((mode & may) == mode) @@ -234,6 +242,24 @@ out_audit: return rc; } +/** + * smk_curacc - determine if current has a specific access to an object + * @obj_label: a pointer to the object's Smack label + * @mode: the access requested, in "MAY" format + * @a : common audit data + * + * This function checks the current subject label/object label pair + * in the access rule list and returns 0 if the access is permitted, + * non zero otherwise. It allows that current may have the capability + * to override the rules. + */ +int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) +{ + struct task_smack *tsp = current_security(); + + return smk_tskacc(tsp, obj_label, mode, a); +} + #ifdef CONFIG_AUDIT /** * smack_str_from_perm : helper to transalate an int to a @@ -245,6 +271,7 @@ out_audit: static inline void smack_str_from_perm(char *string, int access) { int i = 0; + if (access & MAY_READ) string[i++] = 'r'; if (access & MAY_WRITE) @@ -255,6 +282,8 @@ static inline void smack_str_from_perm(char *string, int access) string[i++] = 'a'; if (access & MAY_TRANSMUTE) string[i++] = 't'; + if (access & MAY_LOCK) + string[i++] = 'l'; string[i] = '\0'; } /** @@ -275,7 +304,10 @@ static void smack_log_callback(struct audit_buffer *ab, void *a) audit_log_untrustedstring(ab, sad->subject); audit_log_format(ab, " object="); audit_log_untrustedstring(ab, sad->object); - audit_log_format(ab, " requested=%s", sad->request); + if (sad->request[0] == '\0') + audit_log_format(ab, " labels_differ"); + else + audit_log_format(ab, " requested=%s", sad->request); } /** diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 8825375cc03..f2c30801ce4 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -157,6 +157,74 @@ static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead, return rc; } +/** + * smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_* + * @mode - input mode in form of PTRACE_MODE_* + * + * Returns a converted MAY_* mode usable by smack rules + */ +static inline unsigned int smk_ptrace_mode(unsigned int mode) +{ + switch (mode) { + case PTRACE_MODE_READ: + return MAY_READ; + case PTRACE_MODE_ATTACH: + return MAY_READWRITE; + } + + return 0; +} + +/** + * smk_ptrace_rule_check - helper for ptrace access + * @tracer: tracer process + * @tracee_label: label of the process that's about to be traced, + * the pointer must originate from smack structures + * @mode: ptrace attachment mode (PTRACE_MODE_*) + * @func: name of the function that called us, used for audit + * + * Returns 0 on access granted, -error on error + */ +static int smk_ptrace_rule_check(struct task_struct *tracer, char *tracee_label, + unsigned int mode, const char *func) +{ + int rc; + struct smk_audit_info ad, *saip = NULL; + struct task_smack *tsp; + struct smack_known *skp; + + if ((mode & PTRACE_MODE_NOAUDIT) == 0) { + smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK); + smk_ad_setfield_u_tsk(&ad, tracer); + saip = &ad; + } + + tsp = task_security(tracer); + skp = smk_of_task(tsp); + + if ((mode & PTRACE_MODE_ATTACH) && + (smack_ptrace_rule == SMACK_PTRACE_EXACT || + smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) { + if (skp->smk_known == tracee_label) + rc = 0; + else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN) + rc = -EACCES; + else if (capable(CAP_SYS_PTRACE)) + rc = 0; + else + rc = -EACCES; + + if (saip) + smack_log(skp->smk_known, tracee_label, 0, rc, saip); + + return rc; + } + + /* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */ + rc = smk_tskacc(tsp, tracee_label, smk_ptrace_mode(mode), saip); + return rc; +} + /* * LSM hooks. * We he, that is fun! @@ -165,16 +233,15 @@ static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead, /** * smack_ptrace_access_check - Smack approval on PTRACE_ATTACH * @ctp: child task pointer - * @mode: ptrace attachment mode + * @mode: ptrace attachment mode (PTRACE_MODE_*) * * Returns 0 if access is OK, an error code otherwise * - * Do the capability checks, and require read and write. + * Do the capability checks. */ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode) { int rc; - struct smk_audit_info ad; struct smack_known *skp; rc = cap_ptrace_access_check(ctp, mode); @@ -182,10 +249,8 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode) return rc; skp = smk_of_task(task_security(ctp)); - smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); - smk_ad_setfield_u_tsk(&ad, ctp); - rc = smk_curacc(skp->smk_known, MAY_READWRITE, &ad); + rc = smk_ptrace_rule_check(current, skp->smk_known, mode, __func__); return rc; } @@ -195,23 +260,21 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode) * * Returns 0 if access is OK, an error code otherwise * - * Do the capability checks, and require read and write. + * Do the capability checks, and require PTRACE_MODE_ATTACH. */ static int smack_ptrace_traceme(struct task_struct *ptp) { int rc; - struct smk_audit_info ad; struct smack_known *skp; rc = cap_ptrace_traceme(ptp); if (rc != 0) return rc; - skp = smk_of_task(task_security(ptp)); - smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); - smk_ad_setfield_u_tsk(&ad, ptp); + skp = smk_of_task(current_security()); - rc = smk_curacc(skp->smk_known, MAY_READWRITE, &ad); + rc = smk_ptrace_rule_check(ptp, skp->smk_known, + PTRACE_MODE_ATTACH, __func__); return rc; } @@ -219,8 +282,6 @@ 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 +292,7 @@ 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; @@ -341,10 +402,12 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data) struct inode *inode = root->d_inode; struct superblock_smack *sp = sb->s_security; struct inode_smack *isp; + struct smack_known *skp; char *op; char *commap; char *nsp; int transmute = 0; + int specified = 0; if (sp->smk_initialized) return 0; @@ -359,41 +422,65 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data) if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) { op += strlen(SMK_FSHAT); nsp = smk_import(op, 0); - if (nsp != NULL) + if (nsp != NULL) { sp->smk_hat = nsp; + specified = 1; + } } else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) { op += strlen(SMK_FSFLOOR); nsp = smk_import(op, 0); - if (nsp != NULL) + if (nsp != NULL) { sp->smk_floor = nsp; + specified = 1; + } } else if (strncmp(op, SMK_FSDEFAULT, strlen(SMK_FSDEFAULT)) == 0) { op += strlen(SMK_FSDEFAULT); nsp = smk_import(op, 0); - if (nsp != NULL) + if (nsp != NULL) { sp->smk_default = nsp; + specified = 1; + } } else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) { op += strlen(SMK_FSROOT); nsp = smk_import(op, 0); - if (nsp != NULL) + if (nsp != NULL) { sp->smk_root = nsp; + specified = 1; + } } else if (strncmp(op, SMK_FSTRANS, strlen(SMK_FSTRANS)) == 0) { op += strlen(SMK_FSTRANS); nsp = smk_import(op, 0); if (nsp != NULL) { sp->smk_root = nsp; transmute = 1; + specified = 1; } } } + if (!smack_privileged(CAP_MAC_ADMIN)) { + /* + * Unprivileged mounts don't get to specify Smack values. + */ + if (specified) + return -EPERM; + /* + * Unprivileged mounts get root and default from the caller. + */ + skp = smk_of_current(); + sp->smk_root = skp->smk_known; + sp->smk_default = skp->smk_known; + } /* * Initialize the root inode. */ isp = inode->i_security; - if (inode->i_security == NULL) { - inode->i_security = new_inode_smack(sp->smk_root); - isp = inode->i_security; + if (isp == NULL) { + isp = new_inode_smack(sp->smk_root); + if (isp == NULL) + return -ENOMEM; + inode->i_security = isp; } else isp->smk_inode = sp->smk_root; @@ -423,53 +510,6 @@ static int smack_sb_statfs(struct dentry *dentry) return rc; } -/** - * smack_sb_mount - Smack check for mounting - * @dev_name: unused - * @path: mount point - * @type: unused - * @flags: unused - * @data: unused - * - * Returns 0 if current can write the floor of the filesystem - * being mounted on, an error code otherwise. - */ -static int smack_sb_mount(const char *dev_name, struct path *path, - const char *type, unsigned long flags, void *data) -{ - struct superblock_smack *sbp = path->dentry->d_sb->s_security; - struct smk_audit_info ad; - - smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); - smk_ad_setfield_u_fs_path(&ad, *path); - - return smk_curacc(sbp->smk_floor, MAY_WRITE, &ad); -} - -/** - * smack_sb_umount - Smack check for unmounting - * @mnt: file system to unmount - * @flags: unused - * - * Returns 0 if current can write the floor of the filesystem - * being unmounted, an error code otherwise. - */ -static int smack_sb_umount(struct vfsmount *mnt, int flags) -{ - struct superblock_smack *sbp; - struct smk_audit_info ad; - struct path path; - - path.dentry = mnt->mnt_root; - path.mnt = mnt; - - smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); - smk_ad_setfield_u_fs_path(&ad, path); - - sbp = path.dentry->d_sb->s_security; - return smk_curacc(sbp->smk_floor, MAY_WRITE, &ad); -} - /* * BPRM hooks */ @@ -478,7 +518,7 @@ static int smack_sb_umount(struct vfsmount *mnt, int flags) * smack_bprm_set_creds - set creds for exec * @bprm: the exec information * - * Returns 0 if it gets a blob, -ENOMEM otherwise + * Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise */ static int smack_bprm_set_creds(struct linux_binprm *bprm) { @@ -498,7 +538,22 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm) if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task) return 0; - if (bprm->unsafe) + if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { + struct task_struct *tracer; + rc = 0; + + rcu_read_lock(); + tracer = ptrace_parent(current); + if (likely(tracer != NULL)) + rc = smk_ptrace_rule_check(tracer, + isp->smk_task->smk_known, + PTRACE_MODE_ATTACH, + __func__); + rcu_read_unlock(); + + if (rc != 0) + return rc; + } else if (bprm->unsafe) return -EPERM; bsp->smk_task = isp->smk_task; @@ -837,31 +892,43 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { struct smk_audit_info ad; + struct smack_known *skp; + int check_priv = 0; + int check_import = 0; + int check_star = 0; int rc = 0; + /* + * Check label validity here so import won't fail in post_setxattr + */ 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_SMACKMMAP) == 0) { - if (!smack_privileged(CAP_MAC_ADMIN)) - rc = -EPERM; - /* - * check label validity here so import wont fail on - * post_setxattr - */ - if (size == 0 || size >= SMK_LONGLABEL || - smk_import(value, size) == NULL) - rc = -EINVAL; + strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) { + check_priv = 1; + check_import = 1; + } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0 || + strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { + check_priv = 1; + check_import = 1; + check_star = 1; } else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) { - if (!smack_privileged(CAP_MAC_ADMIN)) - rc = -EPERM; + check_priv = 1; if (size != TRANS_TRUE_SIZE || strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0) rc = -EINVAL; } else rc = cap_inode_setxattr(dentry, name, value, size, flags); + if (check_priv && !smack_privileged(CAP_MAC_ADMIN)) + rc = -EPERM; + + if (rc == 0 && check_import) { + skp = smk_import_entry(value, size); + if (skp == NULL || (check_star && + (skp == &smack_known_star || skp == &smack_known_web))) + rc = -EINVAL; + } + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); smk_ad_setfield_u_fs_path_dentry(&ad, dentry); @@ -893,18 +960,20 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name, return; } - skp = smk_import_entry(value, size); if (strcmp(name, XATTR_NAME_SMACK) == 0) { + skp = smk_import_entry(value, size); if (skp != NULL) isp->smk_inode = skp->smk_known; else isp->smk_inode = smack_known_invalid.smk_known; } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) { + skp = smk_import_entry(value, size); if (skp != NULL) isp->smk_task = skp; else isp->smk_task = &smack_known_invalid; } else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { + skp = smk_import_entry(value, size); if (skp != NULL) isp->smk_mmap = skp; else @@ -951,24 +1020,37 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name) strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 || strcmp(name, XATTR_NAME_SMACKEXEC) == 0 || strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 || - strcmp(name, XATTR_NAME_SMACKMMAP)) { + strcmp(name, XATTR_NAME_SMACKMMAP) == 0) { if (!smack_privileged(CAP_MAC_ADMIN)) rc = -EPERM; } else rc = cap_inode_removexattr(dentry, name); + if (rc != 0) + return rc; + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY); smk_ad_setfield_u_fs_path_dentry(&ad, dentry); - if (rc == 0) - rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad); - if (rc == 0) { - isp = dentry->d_inode->i_security; + rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad); + if (rc != 0) + return rc; + + isp = dentry->d_inode->i_security; + /* + * Don't do anything special for these. + * XATTR_NAME_SMACKIPIN + * XATTR_NAME_SMACKIPOUT + * XATTR_NAME_SMACKEXEC + */ + if (strcmp(name, XATTR_NAME_SMACK) == 0) isp->smk_task = NULL; + else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) isp->smk_mmap = NULL; - } + else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) + isp->smk_flags &= ~SMK_INODE_TRANSMUTE; - return rc; + return 0; } /** @@ -1013,7 +1095,7 @@ static int smack_inode_getsecurity(const struct inode *inode, ssp = sock->sk->sk_security; if (strcmp(name, XATTR_SMACK_IPIN) == 0) - isp = ssp->smk_in; + isp = ssp->smk_in->smk_known; else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) isp = ssp->smk_out->smk_known; else @@ -1146,7 +1228,7 @@ static int smack_file_ioctl(struct file *file, unsigned int cmd, * @file: the object * @cmd: unused * - * Returns 0 if current has write access, error code otherwise + * Returns 0 if current has lock access, error code otherwise */ static int smack_file_lock(struct file *file, unsigned int cmd) { @@ -1154,7 +1236,7 @@ static int smack_file_lock(struct file *file, unsigned int cmd) smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); smk_ad_setfield_u_fs_path(&ad, file->f_path); - return smk_curacc(file->f_security, MAY_WRITE, &ad); + return smk_curacc(file->f_security, MAY_LOCK, &ad); } /** @@ -1178,8 +1260,13 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd, switch (cmd) { case F_GETLK: + break; case F_SETLK: case F_SETLKW: + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); + smk_ad_setfield_u_fs_path(&ad, file->f_path); + rc = smk_curacc(file->f_security, MAY_LOCK, &ad); + break; case F_SETOWN: case F_SETSIG: smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); @@ -1359,7 +1446,7 @@ static int smack_file_receive(struct file *file) int may = 0; struct smk_audit_info ad; - smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK); + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); smk_ad_setfield_u_fs_path(&ad, file->f_path); /* * This code relies on bitmasks. @@ -1375,19 +1462,32 @@ static int smack_file_receive(struct file *file) /** * smack_file_open - Smack dentry open processing * @file: the object - * @cred: unused + * @cred: task credential * * Set the security blob in the file structure. + * Allow the open only if the task has read access. There are + * many read operations (e.g. fstat) that you can do with an + * fd even if you have the file open write-only. * * Returns 0 */ static int smack_file_open(struct file *file, const struct cred *cred) { + struct task_smack *tsp = cred->security; struct inode_smack *isp = file_inode(file)->i_security; + struct smk_audit_info ad; + int rc; - file->f_security = isp->smk_inode; + if (smack_privileged(CAP_MAC_OVERRIDE)) + return 0; - return 0; + smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH); + smk_ad_setfield_u_fs_path(&ad, file->f_path); + rc = smk_access(tsp->smk_task, isp->smk_inode, MAY_READ, &ad); + if (rc == 0) + file->f_security = isp->smk_inode; + + return rc; } /* @@ -1772,7 +1872,7 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags) if (ssp == NULL) return -ENOMEM; - ssp->smk_in = skp->smk_known; + ssp->smk_in = skp; ssp->smk_out = skp; ssp->smk_packet = NULL; @@ -2012,7 +2112,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address, if (act == SMK_RECEIVING) { skp = smack_net_ambient; - object = ssp->smk_in; + object = ssp->smk_in->smk_known; } else { skp = ssp->smk_out; object = smack_net_ambient->smk_known; @@ -2042,9 +2142,9 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address, list_for_each_entry(spp, &smk_ipv6_port_list, list) { if (spp->smk_port != port) continue; - object = spp->smk_in; + object = spp->smk_in->smk_known; if (act == SMK_CONNECTING) - ssp->smk_packet = spp->smk_out->smk_known; + ssp->smk_packet = spp->smk_out; break; } @@ -2084,7 +2184,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name, int rc = 0; if (value == NULL || size > SMK_LONGLABEL || size == 0) - return -EACCES; + return -EINVAL; skp = smk_import_entry(value, size); if (skp == NULL) @@ -2108,7 +2208,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name, ssp = sock->sk->sk_security; if (strcmp(name, XATTR_SMACK_IPIN) == 0) - ssp->smk_in = skp->smk_known; + ssp->smk_in = skp; else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) { ssp->smk_out = skp; if (sock->sk->sk_family == PF_INET) { @@ -2721,6 +2821,15 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) * of the superblock. */ if (opt_dentry->d_parent == opt_dentry) { + if (sbp->s_magic == CGROUP_SUPER_MAGIC) { + /* + * The cgroup filesystem is never mounted, + * so there's no opportunity to set the mount + * options. + */ + sbsp->smk_root = smack_known_star.smk_known; + sbsp->smk_default = smack_known_star.smk_known; + } isp->smk_inode = sbsp->smk_root; isp->smk_flags |= SMK_INODE_INSTANT; goto unlockandout; @@ -2734,16 +2843,20 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) */ switch (sbp->s_magic) { case SMACK_MAGIC: + case PIPEFS_MAGIC: + case SOCKFS_MAGIC: + case CGROUP_SUPER_MAGIC: /* * Casey says that it's a little embarrassing * that the smack file system doesn't do * extended attributes. - */ - final = smack_known_star.smk_known; - break; - case PIPEFS_MAGIC: - /* + * * Casey says pipes are easy (?) + * + * Socket access is controlled by the socket + * structures associated with the task involved. + * + * Cgroupfs is special */ final = smack_known_star.smk_known; break; @@ -2755,13 +2868,6 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) */ final = ckp->smk_known; break; - case SOCKFS_MAGIC: - /* - * Socket access is controlled by the socket - * structures associated with the task involved. - */ - final = smack_known_star.smk_known; - break; case PROC_SUPER_MAGIC: /* * Casey says procfs appears not to care. @@ -2842,8 +2948,17 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) if (rc >= 0) transflag = SMK_INODE_TRANSMUTE; } - isp->smk_task = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); - isp->smk_mmap = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp); + /* + * Don't let the exec or mmap label be "*" or "@". + */ + skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); + if (skp == &smack_known_star || skp == &smack_known_web) + skp = NULL; + isp->smk_task = skp; + skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp); + if (skp == &smack_known_star || skp == &smack_known_web) + skp = NULL; + isp->smk_mmap = skp; dput(dp); break; @@ -2958,30 +3073,34 @@ static int smack_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk) { struct smack_known *skp; + struct smack_known *okp; struct socket_smack *ssp = sock->sk_security; struct socket_smack *osp = other->sk_security; struct socket_smack *nsp = newsk->sk_security; struct smk_audit_info ad; int rc = 0; - #ifdef CONFIG_AUDIT struct lsm_network_audit net; - - smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); - smk_ad_setfield_u_net_sk(&ad, other); #endif if (!smack_privileged(CAP_MAC_OVERRIDE)) { skp = ssp->smk_out; - rc = smk_access(skp, osp->smk_in, MAY_WRITE, &ad); + okp = osp->smk_out; +#ifdef CONFIG_AUDIT + smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net); + smk_ad_setfield_u_net_sk(&ad, other); +#endif + rc = smk_access(skp, okp->smk_known, MAY_WRITE, &ad); + if (rc == 0) + rc = smk_access(okp, okp->smk_known, MAY_WRITE, NULL); } /* * Cross reference the peer labels for SO_PEERSEC. */ if (rc == 0) { - nsp->smk_packet = ssp->smk_out->smk_known; - ssp->smk_packet = osp->smk_out->smk_known; + nsp->smk_packet = ssp->smk_out; + ssp->smk_packet = osp->smk_out; } return rc; @@ -3013,7 +3132,7 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other) return 0; skp = ssp->smk_out; - return smk_access(skp, osp->smk_in, MAY_WRITE, &ad); + return smk_access(skp, osp->smk_in->smk_known, MAY_WRITE, &ad); } /** @@ -3108,7 +3227,7 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap, if (found) return skp; - if (ssp != NULL && ssp->smk_in == smack_known_star.smk_known) + if (ssp != NULL && ssp->smk_in == &smack_known_star) return &smack_known_web; return &smack_known_star; } @@ -3227,7 +3346,7 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) * This is the simplist possible security model * for networking. */ - rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad); + rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad); if (rc != 0) netlbl_skbuff_err(skb, rc, 0); break; @@ -3262,7 +3381,7 @@ static int smack_socket_getpeersec_stream(struct socket *sock, ssp = sock->sk->sk_security; if (ssp->smk_packet != NULL) { - rcp = ssp->smk_packet; + rcp = ssp->smk_packet->smk_known; slen = strlen(rcp) + 1; } @@ -3347,7 +3466,7 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent) return; ssp = sk->sk_security; - ssp->smk_in = skp->smk_known; + ssp->smk_in = skp; ssp->smk_out = skp; /* cssp->smk_packet is already set in smack_inet_csk_clone() */ } @@ -3407,7 +3526,7 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb, * Receiving a packet requires that the other end be able to write * here. Read access is not required. */ - rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad); + rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad); if (rc != 0) return rc; @@ -3451,7 +3570,7 @@ static void smack_inet_csk_clone(struct sock *sk, if (req->peer_secid != 0) { skp = smack_from_secid(req->peer_secid); - ssp->smk_packet = skp->smk_known; + ssp->smk_packet = skp; } else ssp->smk_packet = NULL; } @@ -3505,11 +3624,12 @@ static void smack_key_free(struct key *key) * an error code otherwise */ static int smack_key_permission(key_ref_t key_ref, - const struct cred *cred, key_perm_t perm) + const struct cred *cred, unsigned perm) { struct key *keyp; struct smk_audit_info ad; struct smack_known *tkp = smk_of_task(cred->security); + int request = 0; keyp = key_ref_to_ptr(key_ref); if (keyp == NULL) @@ -3530,7 +3650,11 @@ static int smack_key_permission(key_ref_t key_ref, ad.a.u.key_struct.key = keyp->serial; ad.a.u.key_struct.key_desc = keyp->description; #endif - return smk_access(tkp, keyp->security, MAY_READWRITE, &ad); + if (perm & KEY_NEED_READ) + request = MAY_READ; + if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR)) + request = MAY_WRITE; + return smk_access(tkp, keyp->security, request, &ad); } #endif /* CONFIG_KEYS */ @@ -3615,9 +3739,8 @@ static int smack_audit_rule_match(u32 secid, u32 field, u32 op, void *vrule, struct smack_known *skp; char *rule = vrule; - if (!rule) { - audit_log(actx, GFP_ATOMIC, AUDIT_SELINUX_ERR, - "Smack: missing rule\n"); + if (unlikely(!rule)) { + WARN_ONCE(1, "Smack: missing rule\n"); return -ENOENT; } @@ -3738,8 +3861,6 @@ struct security_operations smack_ops = { .sb_copy_data = smack_sb_copy_data, .sb_kern_mount = smack_sb_kern_mount, .sb_statfs = smack_sb_statfs, - .sb_mount = smack_sb_mount, - .sb_umount = smack_sb_umount, .bprm_set_creds = smack_bprm_set_creds, .bprm_committing_creds = smack_bprm_committing_creds, diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 80f4b4a4572..32b24882084 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -52,6 +52,8 @@ 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) */ + SMK_PTRACE = 21, /* set ptrace rule */ }; /* @@ -59,6 +61,7 @@ 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 +93,22 @@ 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; + +/* + * Ptrace current rule + * SMACK_PTRACE_DEFAULT regular smack ptrace rules (/proc based) + * SMACK_PTRACE_EXACT labels must match, but can be overriden with + * CAP_SYS_PTRACE + * SMACK_PTRACE_DRACONIAN lables must match, CAP_SYS_PTRACE has no effect + */ +int smack_ptrace_rule = SMACK_PTRACE_DEFAULT; /* * Certain IP addresses may be designated as single label hosts. @@ -139,7 +157,7 @@ const char *smack_cipso_option = SMACK_CIPSO_OPTION; * SMK_LOADLEN: Smack rule length */ #define SMK_OACCESS "rwxa" -#define SMK_ACCESS "rwxat" +#define SMK_ACCESS "rwxatl" #define SMK_OACCESSLEN (sizeof(SMK_OACCESS) - 1) #define SMK_ACCESSLEN (sizeof(SMK_ACCESS) - 1) #define SMK_OLOADLEN (SMK_LABELLEN + SMK_LABELLEN + SMK_OACCESSLEN) @@ -282,6 +300,10 @@ static int smk_perm_from_str(const char *string) case 'T': perm |= MAY_TRANSMUTE; break; + case 'l': + case 'L': + perm |= MAY_LOCK; + break; default: return perm; } @@ -297,7 +319,8 @@ static int smk_perm_from_str(const char *string) * @import: if non-zero, import labels * @len: label length limit * - * Returns 0 on success, -1 on failure + * Returns 0 on success, -EINVAL on failure and -ENOENT when either subject + * or object is missing. */ static int smk_fill_rule(const char *subject, const char *object, const char *access1, const char *access2, @@ -310,28 +333,28 @@ static int smk_fill_rule(const char *subject, const char *object, if (import) { rule->smk_subject = smk_import_entry(subject, len); if (rule->smk_subject == NULL) - return -1; + return -EINVAL; rule->smk_object = smk_import(object, len); if (rule->smk_object == NULL) - return -1; + return -EINVAL; } else { cp = smk_parse_smack(subject, len); if (cp == NULL) - return -1; + return -EINVAL; skp = smk_find_entry(cp); kfree(cp); if (skp == NULL) - return -1; + return -ENOENT; rule->smk_subject = skp; cp = smk_parse_smack(object, len); if (cp == NULL) - return -1; + return -EINVAL; skp = smk_find_entry(cp); kfree(cp); if (skp == NULL) - return -1; + return -ENOENT; rule->smk_object = skp->smk_known; } @@ -377,6 +400,7 @@ static ssize_t smk_parse_long_rule(char *data, struct smack_parsed_rule *rule, { ssize_t cnt = 0; char *tok[4]; + int rc; int i; /* @@ -401,10 +425,8 @@ static ssize_t smk_parse_long_rule(char *data, struct smack_parsed_rule *rule, while (i < 4) tok[i++] = NULL; - if (smk_fill_rule(tok[0], tok[1], tok[2], tok[3], rule, import, 0)) - return -1; - - return cnt; + rc = smk_fill_rule(tok[0], tok[1], tok[2], tok[3], rule, import, 0); + return rc == 0 ? cnt : rc; } #define SMK_FIXED24_FMT 0 /* Fixed 24byte label format */ @@ -452,7 +474,7 @@ static ssize_t smk_write_rules_list(struct file *file, const char __user *buf, /* * Minor hack for backward compatibility */ - if (count != SMK_OLOADLEN && count != SMK_LOADLEN) + if (count < SMK_OLOADLEN || count > SMK_LOADLEN) return -EINVAL; } else { if (count >= PAGE_SIZE) { @@ -592,6 +614,8 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max) seq_putc(s, 'a'); if (srp->smk_access & MAY_TRANSMUTE) seq_putc(s, 't'); + if (srp->smk_access & MAY_LOCK) + seq_putc(s, 'l'); seq_putc(s, '\n'); } @@ -1169,7 +1193,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf, data[count] = '\0'; - rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd/%d %s", + rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd/%u %s", &host[0], &host[1], &host[2], &host[3], &m, smack); if (rc != 6) { rc = sscanf(data, "%hhd.%hhd.%hhd.%hhd %s", @@ -1597,7 +1621,7 @@ 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 @@ -1616,7 +1640,7 @@ 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; @@ -1627,7 +1651,7 @@ 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 @@ -1650,7 +1674,7 @@ 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); @@ -1670,7 +1694,7 @@ 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; @@ -1850,11 +1874,12 @@ static ssize_t smk_user_access(struct file *file, const char __user *buf, res = smk_parse_long_rule(data, &rule, 0, 3); } - if (res < 0) + if (res >= 0) + res = smk_access(rule.smk_subject, rule.smk_object, + rule.smk_access1, NULL); + else if (res != -ENOENT) return -EINVAL; - res = smk_access(rule.smk_subject, rule.smk_object, - rule.smk_access1, NULL); data[0] = res == 0 ? '1' : '0'; data[1] = '\0'; @@ -2137,7 +2162,7 @@ static ssize_t smk_write_change_rule(struct file *file, const char __user *buf, /* * Must have privilege. */ - if (!capable(CAP_MAC_ADMIN)) + if (!smack_privileged(CAP_MAC_ADMIN)) return -EPERM; return smk_write_rules_list(file, buf, count, ppos, NULL, NULL, @@ -2152,12 +2177,151 @@ 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_read_ptrace - read() for /smack/ptrace + * @filp: file pointer, not actually used + * @buf: where to put the result + * @count: maximum to send along + * @ppos: where to start + * + * Returns number of bytes read or error code, as appropriate + */ +static ssize_t smk_read_ptrace(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + char temp[32]; + ssize_t rc; + + if (*ppos != 0) + return 0; + + sprintf(temp, "%d\n", smack_ptrace_rule); + rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp)); + return rc; +} + +/** + * smk_write_ptrace - write() for /smack/ptrace + * @file: file pointer + * @buf: data from user space + * @count: bytes sent + * @ppos: where to start - must be 0 + */ +static ssize_t smk_write_ptrace(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + char temp[32]; + int i; + + if (!smack_privileged(CAP_MAC_ADMIN)) + return -EPERM; + + if (*ppos != 0 || count >= sizeof(temp) || count == 0) + return -EINVAL; + + if (copy_from_user(temp, buf, count) != 0) + return -EFAULT; + + temp[count] = '\0'; + + if (sscanf(temp, "%d", &i) != 1) + return -EINVAL; + if (i < SMACK_PTRACE_DEFAULT || i > SMACK_PTRACE_MAX) + return -EINVAL; + smack_ptrace_rule = i; + + return count; +} + +static const struct file_operations smk_ptrace_ops = { + .write = smk_write_ptrace, + .read = smk_read_ptrace, + .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 */ @@ -2202,6 +2366,10 @@ 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}, + [SMK_PTRACE] = { + "ptrace", &smk_ptrace_ops, S_IRUGO|S_IWUSR}, /* last one */ {""} }; |