[RFC][PATCH] (#7U5) [2-6.12-rc3-mm3] file system auditing

Hello, I've pulled the latest git-audit tree but I need to take some time to make a clean patch against it.  So, in the meantime, I've patched the 2.6.12-rc3-mm3 tree for comments. Patch appears at bottom of message. Let's discuss locking first.  I've tried to incorporate the BANGing feedback I received *slaps knee* as well as making some adjustments of my own.   * I've removed the path_lookup() that was nestled between the global audit_master_watchlist_lock spinlock in audit_to_transport.  This was admittedly stupid and is now an exercise for user space. * I've completely removed the audit_master_watchlist_lock spinlock to protect the master watchlist, in favor of RCU locking.  To protect against concurrent watch removals from the master watchlist, we conveniently use the local data->lock rw_lock in place of another spinlock.  Thus, only one removal can occur at a time.  To prevent the "rug being pulled out form under us" while we're reading the master watchlist, we defer putting our reference back to the wentry until the current reader is finished.   I'm thinking about removing the local locks on inode audit data in favor of a global spinlock in auditfs to dispell contention between multiple writers and switching its list primitives to RCU as well.  Any opinions on this matter? * Since we can only ever have one insertion into the watchlist at a time, we never have to worry about racing with another insertion.. so the locking here was removed.  Objections? And now, the pinning. * struct audit_wentry was augmented with struct dentry *w_dentry which holds a reference to the pinned dentry. * Three new functions were added: audit_pin, audit_unpin, and audit_dentry_unpin.   audit_pin: Grab a reference to a dentry and store it at its wentry->w_dentry.  The only time we can truly know when to pin a dentry is in the audit_update_watch() hook. audit_unpin: Put back the wentry->w_dentry reference.  For most cases we're able to unpin memory from within the auditfs mechanism itself.  For instance, when the watch is removed, but the file still it exists, or when the watch is removed and while the file does not exist. audit_dentry_unpin: This hook is called from d_delete so that we may release the wentry->w_dentry should it have a reference... otherwise very bad things will happen :-):-)  This is to cover the case when the watch exists, but the file is "removed" (when the dentry is deleted), which cannot be handled internally by audit_unpin. Finally, there were some other minor fixes and cleanups introduced by Steve which I've absorbed (and cleaned up where necessary). -tim diff -Nurp linux-2.6.12-rc3-mm3~orig/fs/dcache.c linux-2.6.12-rc3-mm3~audit/fs/dcache.c --- linux-2.6.12-rc3-mm3~orig/fs/dcache.c 2005-05-06 13:05:08.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/fs/dcache.c 2005-05-10 23:37:50.000000000 -0500 @@ -32,6 +32,7 @@ #include <linux/seqlock.h> #include <linux/swap.h> #include <linux/bootmem.h> +#include <linux/audit.h> /* #define DCACHE_DEBUG 1 */ @@ -97,6 +98,7 @@ static inline void dentry_iput(struct de { struct inode *inode = dentry->d_inode; if (inode) { + audit_update_watch(dentry, 1); dentry->d_inode = NULL; list_del_init(&dentry->d_alias); spin_unlock(&dentry->d_lock); @@ -802,6 +804,7 @@ void d_instantiate(struct dentry *entry, if (inode) list_add(&entry->d_alias, &inode->i_dentry); entry->d_inode = inode; + audit_update_watch(entry, 0); spin_unlock(&dcache_lock); security_d_instantiate(entry, inode); } @@ -978,6 +981,7 @@ struct dentry *d_splice_alias(struct ino new = __d_find_alias(inode, 1); if (new) { BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED)); + audit_update_watch(new, 0); spin_unlock(&dcache_lock); security_d_instantiate(new, inode); d_rehash(dentry); @@ -987,6 +991,7 @@ struct dentry *d_splice_alias(struct ino /* d_instantiate takes dcache_lock, so we do it by hand */ list_add(&dentry->d_alias, &inode->i_dentry); dentry->d_inode = inode; + audit_update_watch(dentry, 0); spin_unlock(&dcache_lock); security_d_instantiate(dentry, inode); d_rehash(dentry); @@ -1090,6 +1095,7 @@ struct dentry * __d_lookup(struct dentry if (!d_unhashed(dentry)) { atomic_inc(&dentry->d_count); found = dentry; + audit_update_watch(found, 0); } spin_unlock(&dentry->d_lock); break; @@ -1170,6 +1176,9 @@ void d_delete(struct dentry * dentry) */ spin_lock(&dcache_lock); spin_lock(&dentry->d_lock); + + audit_dentry_unpin(dentry); + if (atomic_read(&dentry->d_count) == 1) { dentry_iput(dentry); return; @@ -1299,6 +1308,8 @@ void d_move(struct dentry * dentry, stru spin_lock(&target->d_lock); } + audit_update_watch(dentry, 1); + /* Move the dentry to the target hash queue, if on different bucket */ if (dentry->d_flags & DCACHE_UNHASHED) goto already_unhashed; @@ -1332,6 +1343,7 @@ already_unhashed: list_add(&target->d_child, &target->d_parent->d_subdirs); } + audit_update_watch(dentry, 0); list_add(&dentry->d_child, &dentry->d_parent->d_subdirs); spin_unlock(&target->d_lock); spin_unlock(&dentry->d_lock); diff -Nurp linux-2.6.12-rc3-mm3~orig/fs/inode.c linux-2.6.12-rc3-mm3~audit/fs/inode.c --- linux-2.6.12-rc3-mm3~orig/fs/inode.c 2005-05-06 13:05:08.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/fs/inode.c 2005-05-06 14:29:04.000000000 -0500 @@ -22,6 +22,7 @@ #include <linux/cdev.h> #include <linux/bootmem.h> #include <linux/inotify.h> +#include <linux/audit.h> /* * This is needed for the following functions: @@ -139,9 +140,11 @@ static struct inode *alloc_inode(struct inode->i_bdev = NULL; inode->i_cdev = NULL; inode->i_rdev = 0; + inode->i_audit = NULL; inode->i_security = NULL; inode->dirtied_when = 0; - if (security_inode_alloc(inode)) { + if (audit_inode_alloc(inode) || security_inode_alloc(inode)) { + audit_inode_free(inode); if (inode->i_sb->s_op->destroy_inode) inode->i_sb->s_op->destroy_inode(inode); else @@ -179,6 +182,7 @@ void destroy_inode(struct inode *inode) { if (inode_has_buffers(inode)) BUG(); + audit_inode_free(inode); security_inode_free(inode); if (inode->i_sb->s_op->destroy_inode) inode->i_sb->s_op->destroy_inode(inode); diff -Nurp linux-2.6.12-rc3-mm3~orig/fs/namei.c linux-2.6.12-rc3-mm3~audit/fs/namei.c --- linux-2.6.12-rc3-mm3~orig/fs/namei.c 2005-05-06 13:05:09.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/fs/namei.c 2005-05-06 14:29:04.000000000 -0500 @@ -225,6 +225,8 @@ int permission(struct inode *inode, int { int retval, submask; + audit_notify_watch(inode, mask); + if (mask & MAY_WRITE) { umode_t mode = inode->i_mode; @@ -358,6 +360,8 @@ static inline int exec_permission_lite(s if (inode->i_op && inode->i_op->permission) return -EAGAIN; + audit_notify_watch(inode, MAY_EXEC); + if (current->fsuid == inode->i_uid) mode >>= 6; else if (in_group_p(inode->i_gid)) @@ -1172,6 +1176,8 @@ static inline int may_delete(struct inod BUG_ON(victim->d_parent->d_inode != dir); + audit_notify_watch(victim->d_inode, MAY_WRITE); + error = permission(dir,MAY_WRITE | MAY_EXEC, NULL); if (error) return error; @@ -1296,6 +1302,7 @@ int vfs_create(struct inode *dir, struct DQUOT_INIT(dir); error = dir->i_op->create(dir, dentry, mode, nd); if (!error) { + audit_notify_watch(dentry->d_inode, MAY_WRITE); fsnotify_create(dir, dentry->d_name.name); security_inode_post_create(dir, dentry, mode); } @@ -1601,6 +1608,7 @@ int vfs_mknod(struct inode *dir, struct DQUOT_INIT(dir); error = dir->i_op->mknod(dir, dentry, mode, dev); if (!error) { + audit_notify_watch(dentry->d_inode, MAY_WRITE); fsnotify_create(dir, dentry->d_name.name); security_inode_post_mknod(dir, dentry, mode, dev); } @@ -1674,6 +1682,7 @@ int vfs_mkdir(struct inode *dir, struct DQUOT_INIT(dir); error = dir->i_op->mkdir(dir, dentry, mode); if (!error) { + audit_notify_watch(dentry->d_inode, MAY_WRITE); fsnotify_mkdir(dir, dentry->d_name.name); security_inode_post_mkdir(dir,dentry, mode); } @@ -1915,6 +1924,7 @@ int vfs_symlink(struct inode *dir, struc DQUOT_INIT(dir); error = dir->i_op->symlink(dir, dentry, oldname); if (!error) { + audit_notify_watch(dentry->d_inode, MAY_WRITE); fsnotify_create(dir, dentry->d_name.name); security_inode_post_symlink(dir, dentry, oldname); } @@ -1988,6 +1998,7 @@ int vfs_link(struct dentry *old_dentry, error = dir->i_op->link(old_dentry, dir, new_dentry); up(&old_dentry->d_inode->i_sem); if (!error) { + audit_notify_watch(new_dentry->d_inode, MAY_WRITE); fsnotify_create(dir, new_dentry->d_name.name); security_inode_post_link(old_dentry, dir, new_dentry); } @@ -2111,6 +2122,7 @@ static int vfs_rename_dir(struct inode * } if (!error) { d_move(old_dentry,new_dentry); + audit_notify_watch(old_dentry->d_inode, MAY_WRITE); security_inode_post_rename(old_dir, old_dentry, new_dir, new_dentry); } @@ -2139,6 +2151,7 @@ static int vfs_rename_other(struct inode /* The following d_move() should become unconditional */ if (!(old_dir->i_sb->s_type->fs_flags & FS_ODD_RENAME)) d_move(old_dentry, new_dentry); + audit_notify_watch(old_dentry->d_inode, MAY_WRITE); security_inode_post_rename(old_dir, old_dentry, new_dir, new_dentry); } if (target) diff -Nurp linux-2.6.12-rc3-mm3~orig/include/linux/audit.h linux-2.6.12-rc3-mm3~audit/include/linux/audit.h --- linux-2.6.12-rc3-mm3~orig/include/linux/audit.h 2005-05-06 13:05:14.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/include/linux/audit.h 2005-05-10 23:46:30.000000000 -0500 @@ -24,18 +24,29 @@ #ifndef _LINUX_AUDIT_H_ #define _LINUX_AUDIT_H_ +#ifdef __KERNEL__ #include <linux/sched.h> #include <linux/elf.h> + +struct hlist_head; +struct hlist_node; +struct dentry; +struct atomic_t; +#endif + /* Request and reply types */ -#define AUDIT_GET 1000 /* Get status */ -#define AUDIT_SET 1001 /* Set status (enable/disable/auditd) */ -#define AUDIT_LIST 1002 /* List filtering rules */ -#define AUDIT_ADD 1003 /* Add filtering rule */ -#define AUDIT_DEL 1004 /* Delete filtering rule */ -#define AUDIT_USER 1005 /* Send a message from user-space */ -#define AUDIT_LOGIN 1006 /* Define the login id and informaiton */ -#define AUDIT_KERNEL 2000 /* Asynchronous audit record. NOT A REQUEST. */ +#define AUDIT_GET 1000 /* Get status */ +#define AUDIT_SET 1001 /* Set status (enable/disable/auditd) */ +#define AUDIT_LIST 1002 /* List filtering rules */ +#define AUDIT_ADD 1003 /* Add filtering rule */ +#define AUDIT_DEL 1004 /* Delete filtering rule */ +#define AUDIT_USER 1005 /* Send a message from user-space */ +#define AUDIT_LOGIN 1006 /* Define the login id and informaiton */ +#define AUDIT_WATCH_INS 1007 /* Insert file/dir watch entry */ +#define AUDIT_WATCH_REM 1008 /* Remove file/dir watch entry */ +#define AUDIT_WATCH_LIST 1009 /* List all watches */ +#define AUDIT_KERNEL 2000 /* Asynchronous audit record. NOT A REQUEST. */ /* Rule flags */ #define AUDIT_PER_TASK 0x01 /* Apply rule at task creation (not syscall) */ @@ -132,6 +143,9 @@ #define AUDIT_ARCH_V850 (EM_V850|__AUDIT_ARCH_LE) #define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE) +/* 32 byte max key size */ +#define AUDIT_FILTERKEY_MAX 32 + #ifndef __KERNEL__ struct audit_message { struct nlmsghdr nlh; @@ -159,8 +173,46 @@ struct audit_rule { /* for AUDIT_LIST, __u32 values[AUDIT_MAX_FIELDS]; }; +/* Structure to transport watch data to and from the kernel */ + +struct watch_transport { + __u32 dev_major; + __u32 dev_minor; + __u32 perms; + __u32 valid; + __u32 pathlen; + __u32 fklen; + char buf[0]; +}; + #ifdef __KERNEL__ +/* Structure associated with inode->i_audit */ + +struct audit_inode_data { + struct audit_wentry *wentry; + struct hlist_head watchlist; + rwlock_t lock; +}; + +struct audit_watch { + dev_t dev; /* Superblock device */ + __u32 perms; /* Permissions filtering */ + char *name; /* Watch point beneath parent */ + char *path; /* Insertion path */ + char *filterkey; /* An arbitrary filtering key */ +}; + +struct audit_wentry { + struct rcu_head w_rcu; + struct hlist_node w_node; + struct hlist_node w_master; + struct audit_watch *w_watch; + struct dentry *w_dentry; + atomic_t w_count; + +}; + struct audit_buffer; struct audit_context; struct inode; @@ -190,6 +242,7 @@ extern void audit_get_stamp(struct audit extern int audit_set_loginuid(struct task_struct *task, uid_t loginuid); extern uid_t audit_get_loginuid(struct audit_context *ctx); extern int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode); +extern int audit_notify_watch(struct inode *inode, int mask); #else #define audit_alloc(t) ({ 0; }) #define audit_free(t) do { ; } while (0) @@ -198,8 +251,32 @@ extern int audit_ipc_perms(unsigned long #define audit_getname(n) do { ; } while (0) #define audit_putname(n) do { ; } while (0) #define audit_inode(n,i) do { ; } while (0) +#define audit_receive_filter(t,p,u,s,d,l) ({ -EOPNOTSUPP; }) #define audit_get_loginuid(c) ({ -1; }) #define audit_ipc_perms(q,u,g,m) ({ 0; }) +#define audit_notify_watch(i,m) ({ 0; }) +#endif + +#ifdef CONFIG_AUDITFILESYSTEM +extern int audit_filesystem_init(void); +extern int audit_list_watches(int pid, int seq); +extern int audit_receive_watch(int type, int pid, int uid, int seq, + struct watch_transport *req, uid_t loginuid); +extern int audit_inode_alloc(struct inode *inode); +extern void audit_inode_free(struct inode *inode); +extern void audit_update_watch(struct dentry *dentry, int remove); +extern void audit_wentry_put(struct audit_wentry *wentry); +extern void audit_dentry_unpin(struct dentry *dentry); +extern struct audit_wentry *audit_wentry_get(struct audit_wentry *wentry); +#else +#define audit_filesystem_init() ({ 0; }) +#define audit_list_watches(p,s) ({ -EOPNOTSUPP; }) +#define audit_receive_watch(t,p,u,s,r,l) ({ -EOPNOTSUPP; }) +#define audit_inode_alloc(i) ({ 0; }) +#define audit_inode_free(i) do { ; } while(0) +#define audit_update_watch(d,r) do { ; } while (0) +#define audit_wentry_put(w) do { ; } while(0) +#define audit_wentry_get(w) ({ 0; }) #endif #ifdef CONFIG_AUDIT diff -Nurp linux-2.6.12-rc3-mm3~orig/include/linux/fs.h linux-2.6.12-rc3-mm3~audit/include/linux/fs.h --- linux-2.6.12-rc3-mm3~orig/include/linux/fs.h 2005-05-06 13:05:14.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/include/linux/fs.h 2005-05-06 14:29:04.000000000 -0500 @@ -226,6 +226,7 @@ struct poll_table_struct; struct kstatfs; struct vm_area_struct; struct vfsmount; +struct audit_inode_data; /* Used to be a macro which just called the function, now just a function */ extern void update_atime (struct inode *); @@ -477,6 +478,7 @@ struct inode { struct semaphore inotify_sem; /* protects the watches list */ #endif + struct audit_inode_data *i_audit; unsigned long i_state; unsigned long dirtied_when; /* jiffies of first dirtying */ diff -Nurp linux-2.6.12-rc3-mm3~orig/init/Kconfig linux-2.6.12-rc3-mm3~audit/init/Kconfig --- linux-2.6.12-rc3-mm3~orig/init/Kconfig 2005-05-06 13:05:15.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/init/Kconfig 2005-05-06 14:29:04.000000000 -0500 @@ -180,6 +180,16 @@ config AUDITSYSCALL can be used independently or with another kernel subsystem, such as SELinux. +config AUDITFILESYSTEM + bool "Enable file system auditing support" + depends on AUDITSYSCALL + default n + help + Enable file system auditing for regular files and directories. + When a targeted file or directory is accessed, an audit record + is generated describing the inode accessed, how it was accessed, + and by whom (ie: pid and system call). + config HOTPLUG bool "Support for hot-pluggable devices" if !ARCH_S390 default ARCH_S390 diff -Nurp linux-2.6.12-rc3-mm3~orig/kernel/Makefile linux-2.6.12-rc3-mm3~audit/kernel/Makefile --- linux-2.6.12-rc3-mm3~orig/kernel/Makefile 2005-05-06 13:05:15.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/kernel/Makefile 2005-05-06 14:29:04.000000000 -0500 @@ -25,6 +25,7 @@ obj-$(CONFIG_IKCONFIG_PROC) += configs.o obj-$(CONFIG_STOP_MACHINE) += stop_machine.o obj-$(CONFIG_AUDIT) += audit.o obj-$(CONFIG_AUDITSYSCALL) += auditsc.o +obj-$(CONFIG_AUDITFILESYSTEM) += auditfs.o obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_SYSFS) += ksysfs.o obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o diff -Nurp linux-2.6.12-rc3-mm3~orig/kernel/audit.c linux-2.6.12-rc3-mm3~audit/kernel/audit.c --- linux-2.6.12-rc3-mm3~orig/kernel/audit.c 2005-05-06 13:05:15.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/kernel/audit.c 2005-05-10 11:41:42.000000000 -0500 @@ -112,8 +112,13 @@ static LIST_HEAD(audit_entlist); static LIST_HEAD(audit_extlist); /* The netlink socket is only to be read by 1 CPU, which lets us assume - * that list additions and deletions never happen simultaneiously in - * auditsc.c */ + * that list additions and deletions, and watch insertions never happen + * simultaneiously in auditsc.c and auditfs.c respectively. + * + * Even though there can only be one watch removal via netlink at a time, + * there is still a chance of watch removal via audit_update_watch(). In + * this case, the semaphore is not enough. + */ static DECLARE_MUTEX(audit_netlink_sem); /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting @@ -321,6 +326,9 @@ static int audit_netlink_ok(kernel_cap_t case AUDIT_SET: case AUDIT_ADD: case AUDIT_DEL: + case AUDIT_WATCH_LIST: + case AUDIT_WATCH_INS: + case AUDIT_WATCH_REM: if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL)) err = -EPERM; break; @@ -412,12 +420,19 @@ static int audit_receive_msg(struct sk_b return -EINVAL; /* fallthrough */ case AUDIT_LIST: -#ifdef CONFIG_AUDITSYSCALL err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, uid, seq, data, loginuid); -#else - err = -EOPNOTSUPP; -#endif + break; + case AUDIT_WATCH_LIST: + err = audit_list_watches(pid, seq); + break; + case AUDIT_WATCH_INS: + case AUDIT_WATCH_REM: + if (nlh->nlmsg_len < sizeof(struct watch_transport)) + return -EINVAL; + err = audit_receive_watch(nlh->nlmsg_type, + NETLINK_CB(skb).pid, + uid, seq, data, loginuid); break; default: err = -EINVAL; @@ -559,6 +574,7 @@ static int __init audit_init(void) audit_panic("cannot initialize netlink socket"); audit_initialized = 1; + audit_filesystem_init(); audit_enabled = audit_default; audit_log(NULL, "initialized"); return 0; @@ -586,6 +602,7 @@ int __init audit_init(void) audit_pid = 0; audit_initialized = 1; + audit_filesystem_init(); audit_enabled = audit_default; audit_log(NULL, "initialized"); return 0; diff -Nurp linux-2.6.12-rc3-mm3~orig/kernel/auditfs.c linux-2.6.12-rc3-mm3~audit/kernel/auditfs.c --- linux-2.6.12-rc3-mm3~orig/kernel/auditfs.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.12-rc3-mm3~audit/kernel/auditfs.c 2005-05-11 11:35:27.000000000 -0500 @@ -0,0 +1,674 @@ +/* auditfs.c -- Filesystem auditing support -*- linux-c -*- + * Implements filesystem auditing support, depends on kernel/auditsc.c + * + * Copyright 2005 International Business Machines Corp. (IBM) + * All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + * 02111-1307 USA + * + * Written by Timothy R. Chavez <chavezt(a)us.ibm.com&gt; + * + */ + +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/namei.h> +#include <linux/mount.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/audit.h> +#include <asm/uaccess.h> + + +extern int audit_enabled; + +static kmem_cache_t *audit_watch_cache; +static kmem_cache_t *audit_wentry_cache; + +/* Read-heavy list */ +HLIST_HEAD(audit_master_watchlist); + + +/* Private Interface */ + +/* Unpin the dentry stored at wentry->w_dentry. */ +static inline void audit_unpin(struct audit_wentry *wentry) +{ + if (wentry && wentry->w_dentry) { + dput(wentry->w_dentry); + wentry->w_dentry = NULL; + } +} + +/* Pin the dentry and store it at wentry->w_dentry. */ +static inline void audit_pin(struct audit_wentry *wentry, + struct dentry *dentry) +{ + if (wentry && !wentry->w_dentry) + wentry->w_dentry = dget(dentry); +} + +static inline struct audit_wentry *audit_wentry_fetch(const char *name, + struct audit_inode_data *data) +{ + struct audit_wentry *wentry, *ret = NULL; + struct hlist_node *pos; + + hlist_for_each_entry(wentry, pos, &data->watchlist, w_node) + if(!strcmp(wentry->w_watch->name, name)) { + ret = audit_wentry_get(wentry); + break; + } + + return ret; +} + +static inline struct audit_wentry *audit_wentry_fetch_lock(const char *name, + struct audit_inode_data *data) +{ + struct audit_wentry *ret = NULL; + + if (name && data) { + read_lock(&data->lock); + ret = audit_wentry_fetch(name, data); + read_unlock(&data->lock); + } + + return ret; +} + +static inline struct audit_watch *audit_watch_alloc(void) +{ + struct audit_watch *watch; + + watch = kmem_cache_alloc(audit_watch_cache, GFP_KERNEL); + if (watch) { + watch->name = NULL; + watch->path = NULL; + watch->filterkey = NULL; + watch->perms = 0; + } + + return watch; +} + +static inline void audit_watch_free(struct audit_watch *watch) +{ + if (watch) { + kfree(watch->name); + kfree(watch->path); + kfree(watch->filterkey); + kmem_cache_free(audit_watch_cache, watch); + } +} + +/* Convert a watch_transport structure into a kernel audit_watch structure. */ +static inline struct audit_watch *audit_to_watch(void *memblk) +{ + unsigned int offset; + struct watch_transport *t; + struct audit_watch *watch; + + watch = audit_watch_alloc(); + if (!watch) + goto audit_to_watch_exit; + + t = (struct watch_transport *)memblk; + + watch->perms = t->perms; + + offset = sizeof(struct watch_transport); + watch->filterkey = kmalloc(t->fklen, GFP_KERNEL); + if (!watch->filterkey) + goto audit_to_watch_fail; + watch->filterkey[0] = 0; + strncat(watch->filterkey, memblk + offset, t->fklen); + + offset += t->fklen; + watch->path = kmalloc(t->pathlen, GFP_KERNEL); + if (!watch->path) + goto audit_to_watch_fail; + watch->path[0] = 0; + strncat(watch->path, memblk + offset, t->pathlen); + + goto audit_to_watch_exit; + +audit_to_watch_fail: + audit_watch_free(watch); + watch = NULL; +audit_to_watch_exit: + return watch; +} + +/* + * Convert a kernel audit_watch structure into a watch_transport structure. + * We do this to send watch information back to user space. + */ +static inline void *audit_to_transport(struct audit_watch *watch, size_t size) +{ + unsigned int offset; + struct watch_transport t; + void *memblk; + + memblk = kmalloc(size, GFP_KERNEL); + if (!memblk) + goto audit_to_transport_exit; + + memset(&t, 0, sizeof(t)); + + t.dev_major = MAJOR(watch->dev); + t.dev_minor = MINOR(watch->dev); + t.perms = watch->perms; + t.pathlen = strlen(watch->path) + 1; + if (watch->filterkey) + t.fklen = strlen(watch->filterkey) + 1; + + memcpy(memblk, &t, sizeof(t)); + offset = sizeof(t); + memcpy(memblk + offset, watch->filterkey, t.fklen); + offset += t.fklen; + memcpy(memblk + offset, watch->path, t.pathlen); + +audit_to_transport_exit: + return memblk; +} + +static inline struct audit_watch *audit_create_watch(const char *path, + const char *name, + const char *filterkey, + __u32 perms, dev_t dev) +{ + struct audit_watch *err = NULL; + struct audit_watch *watch = NULL; + + err = ERR_PTR(-ENOMEM); + watch = audit_watch_alloc(); + if (watch) { + watch->path = kmalloc(strlen(path)+1, GFP_KERNEL); + if (!watch->path) + goto audit_create_watch_fail; + strcpy(watch->path, path); + + watch->name = kmalloc(strlen(name)+1, GFP_KERNEL); + if (!watch->name) + goto audit_create_watch_fail; + strcpy(watch->name, name); + + if (filterkey) { + watch->filterkey = kmalloc(strlen(filterkey)+1, + GFP_KERNEL); + if (!watch->filterkey) + goto audit_create_watch_fail; + strcpy(watch->filterkey, filterkey); + } + + watch->dev = dev; + watch->perms = perms; + + goto audit_create_watch_exit; + } + +audit_create_watch_fail: + audit_watch_free(watch); + watch = err; +audit_create_watch_exit: + return watch; +} + +static inline struct audit_wentry *audit_wentry_alloc(void) +{ + struct audit_wentry *wentry; + + wentry = kmem_cache_alloc(audit_wentry_cache, GFP_KERNEL); + if (wentry) { + atomic_set(&wentry->w_count, 1); + wentry->w_watch = NULL; + wentry->w_dentry = NULL; + } + + return wentry; +} + +/* + * If a watch has been removed from a watchlist, we promptly unpin the + * dentry that was being watched, as it is no longer important to us. + */ +static inline void audit_wentry_free(struct audit_wentry *wentry) +{ + if (wentry) { + audit_unpin(wentry); + audit_watch_free(wentry->w_watch); + kmem_cache_free(audit_wentry_cache, wentry); + } +} + +/* + * Protected by audit_netlink_sem, thus there will never be a race on + * insertions as all insertion requests must come through netlink. + */ +static inline int audit_create_wentry(const char *path, + const char *name, + const char *filterkey, + __u32 perms, dev_t dev, + struct audit_inode_data *data) +{ + int ret; + struct audit_wentry *wentry = NULL; + struct audit_wentry *new = NULL; + struct audit_watch *watch; + + ret = -EEXIST; + wentry = audit_wentry_fetch_lock(name, data); + if (wentry) { + audit_wentry_put(wentry); + goto audit_create_wentry_exit; + } + + ret = -ENOMEM; + new = audit_wentry_alloc(); + if (!new) + goto audit_create_wentry_exit; + + watch = audit_create_watch(path, name, filterkey, perms, dev); + if (IS_ERR(watch)) { + ret = PTR_ERR(watch); + audit_wentry_put(new); + goto audit_create_wentry_exit; + } + + ret = 0; + + new->w_watch = watch; + audit_wentry_get(new); + + hlist_add_head_rcu(&new->w_master, &audit_master_watchlist); + hlist_add_head(&new->w_node, &data->watchlist); + +audit_create_wentry_exit: + return ret; +} + +static inline void audit_wentry_rcu_put(struct rcu_head *head) +{ + struct audit_wentry *wentry; + + wentry = container_of(head, struct audit_wentry, w_rcu); + audit_wentry_put(wentry); +} + +/* + * There's three ways we can arrive at audit_destroy_wentry. Two of the ways + * may cause contention with one another, while the third may not. They are: + * + * 1) An administrator has explicitly requested a watch removal + * 2) A directory with an "active" watchlist is rename()'ed + * 3) The inode is in the process of being destroyed + * + * In ways 1) and 2) the data->lock must be held to safely enter. Because + * of this, we're able to remove the watchlist entry from the master list + * as well, without needing an additional spinlock. + * + * If way 3) occurs there will no longer be any reachable references to the + * inode, thus there is only one way to remove this wentry, and no need to + * hold the data->lock. + */ +static inline void audit_destroy_wentry(struct audit_wentry *wentry) +{ + if (wentry) { + hlist_del_init(&wentry->w_node); + audit_wentry_put(wentry); + hlist_del_rcu(&wentry->w_master); + call_rcu(&wentry->w_rcu, audit_wentry_rcu_put); + } +} + + +/* + * We only drain the watchlist in two ways. They are: + * + * 1) Upon deletion of the inode (no contention) + * 2) Upon rename()'ing a directory with an "active" watchlist (contention) + * + * Caller should hold data->lock where contention is possible. + */ +static inline void audit_drain_watchlist(struct audit_inode_data *data) +{ + struct audit_wentry *wentry; + struct hlist_node *pos, *tmp; + + hlist_for_each_entry_safe(wentry, pos, tmp, &data->watchlist, w_node) + audit_destroy_wentry(wentry); +} + +static inline struct audit_inode_data *audit_data_alloc(void) +{ + struct audit_inode_data *data; + + data = kmalloc(sizeof(struct audit_inode_data), GFP_KERNEL); + if (data) { + data->wentry = NULL; + INIT_HLIST_HEAD(&data->watchlist); + data->lock = RW_LOCK_UNLOCKED; + } + + return data; +} + +static inline void audit_data_free(struct audit_inode_data *data) +{ + if (data) { + audit_drain_watchlist(data); + audit_wentry_put(data->wentry); + kfree(data); + } +} + +static inline int audit_insert_watch(struct audit_watch *watch, uid_t loginuid) +{ + int ret; + struct nameidata nd; + + ret = path_lookup(watch->path, LOOKUP_PARENT, &nd); + if (ret < 0) + goto audit_insert_watch_exit; + + ret = -EPERM; + if (nd.last_type != LAST_NORM || !nd.last.name) + goto audit_insert_watch_release; + + ret = audit_create_wentry(watch->path, + nd.last.name, + watch->filterkey, + watch->perms, + nd.dentry->d_inode->i_sb->s_dev, + nd.dentry->d_inode->i_audit); + if (ret < 0) + goto audit_insert_watch_release; + + audit_log(NULL, "auid %u inserted watch\n", loginuid); + /* __d_lookup will attach the audit data, if nd.last exists. */ + dput(d_lookup(nd.dentry, &nd.last)); + +audit_insert_watch_release: + path_release(&nd); +audit_insert_watch_exit: + return ret; +} + +/* + * We hold the data->lock here to eliminate contention between this user space + * request and an action taken by audit_update_watch() in which watch removal + * is also possible when a directory with an "active" watchlist is rename()'ed. + * + */ +static inline int audit_remove_watch(struct audit_watch *watch, uid_t loginuid) +{ + int ret; + struct nameidata nd; + struct audit_inode_data *data; + struct audit_wentry *wentry; + + ret = path_lookup(watch->path, LOOKUP_PARENT, &nd); + if (ret < 0) + goto audit_remove_watch_exit; + + ret = -EPERM; + if (nd.last_type != LAST_NORM || !nd.last.name) + goto audit_remove_watch_release; + + data = nd.dentry->d_inode->i_audit; + + write_lock(&data->lock); + wentry = audit_wentry_fetch(nd.last.name, data); + if (!wentry) { + write_unlock(&data->lock); + goto audit_remove_watch_release; + } + audit_destroy_wentry(wentry); + audit_wentry_put(wentry); + audit_log(NULL, "auid %u removed watch\n", loginuid); + write_unlock(&data->lock); + + ret = 0; + +audit_remove_watch_release: + path_release(&nd); +audit_remove_watch_exit: + return ret; +} + +struct audit_wentry *audit_wentry_get(struct audit_wentry *wentry) +{ + if (wentry) { + BUG_ON(!atomic_read(&wentry->w_count)); + atomic_inc(&wentry->w_count); + } + + return wentry; +} + +void audit_wentry_put(struct audit_wentry *wentry) +{ + if (wentry && atomic_dec_and_test(&wentry->w_count)) + audit_wentry_free(wentry); +} + +/* + * The update hook is responsible for watching and unwatching d_inodes during + * their lifetimes in dcache. Each d_inode being watched is pinned in memory. + * As soon as a d_inode becomes unwatched (ie: dentry is destroyed, watch is + * unhashed / removed from watchlist, dentry is moved out of watch path). + * + * Hook appears in fs/dcache.c: + * d_move(), + * dentry_iput(), + * d_instantiate(), + * d_splice_alias() + * __d_lookup() + */ +void audit_update_watch(struct dentry *dentry, int remove) +{ + struct audit_wentry *wentry; + struct audit_inode_data *data, *parent; + + if (likely(!audit_enabled)) + return; + + if (!dentry || !dentry->d_inode) + return; + + if (!dentry->d_parent || !dentry->d_parent->d_inode) + return; + + data = dentry->d_inode->i_audit; + parent = dentry->d_parent->d_inode->i_audit; + + wentry = audit_wentry_fetch_lock(dentry->d_name.name, parent); + + write_lock(&data->lock); + /* FIXME: long watchlist == too much spinning? */ + if (remove) { + audit_drain_watchlist(data); + if ((wentry && data->wentry) && (wentry == data->wentry)) { + audit_wentry_put(data->wentry); + data->wentry = NULL; + } + } else if (!data->wentry) { + data->wentry = audit_wentry_get(wentry); + audit_pin(data->wentry, dentry); + } else if (hlist_unhashed(&data->wentry->w_node)) { + audit_wentry_put(data->wentry); + data->wentry = audit_wentry_get(wentry); + audit_pin(data->wentry, dentry); + } + write_unlock(&data->lock); + + audit_wentry_put(wentry); +} + +int audit_send_watch(int pid, int seq, struct audit_watch *watch) +{ + int ret; + size_t size; + void *memblk; + + /* We must include space for both "\0" */ + size = sizeof(struct watch_transport) + strlen(watch->path) + + strlen(watch->filterkey) + 2; + + ret = -ENOMEM; + memblk = audit_to_transport(watch, size); + if (!memblk) + goto audit_send_watch_exit; + + ret = 0; + audit_send_reply(pid, seq, AUDIT_WATCH_LIST, 0, 1, memblk, size); + kfree(memblk); + +audit_send_watch_exit: + return ret; +} + +/* + * Read the "master watchlist" which is a watchlist of all watches in the + * file system and send it to user space. There will never be concurrent + * readers of this list. + * + * The reference to wentry will not be put back during a read upon a + * watch removal, until after we're done reading. So, the potential + * for the rug being pulled out from under us is NIL. + * + * This list is only a "snapshot in time". It is not gospel. + */ +int audit_list_watches(int pid, int seq) +{ + int ret = 0; + struct audit_wentry *wentry; + struct hlist_node *pos; + + rcu_read_lock(); + hlist_for_each_entry_rcu(wentry, pos, &audit_master_watchlist, w_master) { + ret = audit_send_watch(pid, seq, wentry->w_watch); + if (ret < 0) + break; + } + rcu_read_unlock(); + + audit_send_reply(pid, seq, AUDIT_WATCH_LIST, 1, 1, NULL, 0); + + return ret; +} + +int audit_receive_watch(int type, int pid, int uid, int seq, + struct watch_transport *req, uid_t loginuid) +{ + int ret = 0; + struct audit_watch *watch = NULL; + + ret = -EINVAL; + if (req->pathlen > PATH_MAX || req->pathlen == 0) + goto audit_receive_watch_exit; + + if (req->fklen > AUDIT_FILTERKEY_MAX) + goto audit_receive_watch_exit; + + if (req->perms > (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND)) + goto audit_receive_watch_exit; + + ret = -ENOMEM; + watch = audit_to_watch(req); + if (!watch) + goto audit_receive_watch_exit; + + switch (type) { + case AUDIT_WATCH_INS: + ret = audit_insert_watch(watch, loginuid); + break; + case AUDIT_WATCH_REM: + ret = audit_remove_watch(watch, loginuid); + break; + default: + ret = -EINVAL; + } + +audit_receive_watch_exit: + audit_watch_free(watch); + return ret; +} + +int audit_inode_alloc(struct inode *inode) +{ + if (inode) { + inode->i_audit = audit_data_alloc(); + if (!inode->i_audit) + return ENOMEM; + } + + return 0; +} + +void audit_inode_free(struct inode *inode) +{ + if (inode) + audit_data_free(inode->i_audit); +} +/* + * When we delete a dentry we check to see whether or not we're being + * watched. If we are watched, we have to put back our reference to + * the dentry to unpin it from memory or bad things happen. + * + * Hook appears in fs/dcache.c:d_delete() + */ +void audit_dentry_unpin(struct dentry *dentry) +{ + struct audit_inode_data *parent; + struct audit_wentry *wentry; + + parent = dentry->d_parent->d_inode->i_audit; + wentry = audit_wentry_fetch_lock(dentry->d_name.name, parent); + if (wentry) { + audit_unpin(dentry->d_inode->i_audit->wentry); + audit_wentry_put(wentry); + } +} + +int audit_filesystem_init(void) +{ + int ret; + + ret = -ENOMEM; + audit_watch_cache = + kmem_cache_create("audit_watch_cache", + sizeof(struct audit_watch), 0, 0, NULL, NULL); + if (!audit_watch_cache) + goto audit_filesystem_init_fail; + + audit_wentry_cache = + kmem_cache_create("audit_wentry_cache", + sizeof(struct audit_wentry), 0, 0, NULL, NULL); + if (!audit_wentry_cache) + goto audit_filesystem_init_fail; + + ret = 0; + goto audit_filesystem_init_exit; + +audit_filesystem_init_fail: + kmem_cache_destroy(audit_watch_cache); + kmem_cache_destroy(audit_wentry_cache); +audit_filesystem_init_exit: + return ret; +} diff -Nurp linux-2.6.12-rc3-mm3~orig/kernel/auditsc.c linux-2.6.12-rc3-mm3~audit/kernel/auditsc.c --- linux-2.6.12-rc3-mm3~orig/kernel/auditsc.c 2005-05-06 13:05:15.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/kernel/auditsc.c 2005-05-06 14:29:04.000000000 -0500 @@ -102,6 +102,7 @@ struct audit_aux_data { }; #define AUDIT_AUX_IPCPERM 0 +#define AUDIT_AUX_WATCH 1 struct audit_aux_data_ipcctl { struct audit_aux_data d; @@ -112,6 +113,16 @@ struct audit_aux_data_ipcctl { mode_t mode; }; +struct audit_aux_data_watched { + struct audit_aux_data link; + struct audit_wentry *wentry; + unsigned long ino; + int mask; + uid_t uid; + gid_t gid; + dev_t dev; + dev_t rdev; +}; /* The per-task audit context. */ struct audit_context { @@ -696,6 +707,24 @@ static void audit_log_exit(struct audit_ audit_log_format(ab, " qbytes=%lx uid=%d gid=%d mode=%x", axi->qbytes, axi->uid, axi->gid, axi->mode); + break; + } + + case AUDIT_AUX_WATCH: { + struct audit_aux_data_watched *axi = (void *)aux; + audit_log_format(ab, " watch="); + audit_log_untrustedstring(ab, axi->wentry->w_watch->name); + audit_log_format(ab, + " filterkey=%s perm=%u perm_mask=%d" + " inode=%lu inode_uid=%d inode_gid=%d" + " inode_dev=%02x:%02x inode_rdev=%02x:%02x", + axi->wentry->w_watch->filterkey, + axi->wentry->w_watch->perms, + axi->mask, axi->ino, axi->uid, axi->gid, + MAJOR(axi->dev), MINOR(axi->dev), + MAJOR(axi->rdev), MINOR(axi->rdev)); + audit_wentry_put(axi->wentry); + break; } } audit_log_end(ab); @@ -1056,3 +1085,52 @@ int audit_ipc_perms(unsigned long qbytes context->aux = (void *)ax; return 0; } + +int audit_notify_watch(struct inode *inode, int mask) +{ + int ret = 0; + struct audit_context *context = current->audit_context; + struct audit_aux_data_watched *ax; + struct audit_wentry *wentry = NULL; + + if (likely(!audit_enabled)) + goto audit_notify_watch_exit; + + if (!inode) + goto audit_notify_watch_exit; + + wentry = audit_wentry_get(inode->i_audit->wentry); + if (!wentry) + goto audit_notify_watch_exit; + + if (mask && (wentry->w_watch->perms && !(wentry->w_watch->perms&mask))) + goto audit_notify_watch_fail; + + ret = -ENOMEM; + ax = kmalloc(sizeof(*ax), GFP_KERNEL); + if (!ax) + goto audit_notify_watch_fail; + + ret = 0; + if (context->in_syscall && !context->auditable) + context->auditable = 1; + + ax->wentry = wentry; + ax->mask = mask; + ax->ino = inode->i_ino; + ax->uid = inode->i_uid; + ax->gid = inode->i_gid; + ax->dev = inode->i_sb->s_dev; + ax->rdev = inode->i_rdev; + + ax->link.type = AUDIT_AUX_WATCH; + ax->link.next = context->aux; + context->aux = (void *)ax; + + goto audit_notify_watch_exit; + +audit_notify_watch_fail: + audit_wentry_put(wentry); +audit_notify_watch_exit: + return ret; +} diff -Nurp linux-2.6.12-rc3-mm3~orig/security/selinux/nlmsgtab.c linux-2.6.12-rc3-mm3~audit/security/selinux/nlmsgtab.c --- linux-2.6.12-rc3-mm3~orig/security/selinux/nlmsgtab.c 2005-05-06 13:05:16.000000000 -0500 +++ linux-2.6.12-rc3-mm3~audit/security/selinux/nlmsgtab.c 2005-05-06 14:29:04.000000000 -0500 @@ -97,6 +97,9 @@ static struct nlmsg_perm nlmsg_audit_per { AUDIT_ADD, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, { AUDIT_DEL, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, { AUDIT_USER, NETLINK_AUDIT_SOCKET__NLMSG_RELAY }, + { AUDIT_WATCH_INS, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, + { AUDIT_WATCH_REM, NETLINK_AUDIT_SOCKET__NLMSG_WRITE }, + { AUDIT_WATCH_LIST, NETLINK_AUDIT_SOCKET__NLMSG_READPRIV }, };