/* auditsc.c -- System-call auditing support * Handles all system-call specific auditing features. * * Copyright 2003-2004 Red Hat Inc., Durham, North Carolina. * 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 Rickard E. (Rik) Faith <faith@redhat.com> * * Many of the ideas implemented here are from Stephen C. Tweedie, * especially the idea of avoiding a copy by using getname. * * The method for actual interception of syscall entry and exit (not in * this file -- see entry.S) is based on a GPL'd patch written by * okir@suse.de and Copyright 2003 SuSE Linux AG. * */ #include <linux/init.h> #include <asm/atomic.h> #include <asm/types.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/mount.h> #include <linux/socket.h> #include <linux/audit.h> #include <linux/personality.h> #include <linux/time.h> #include <linux/kthread.h> #include <linux/netlink.h> #include <linux/compiler.h> #include <asm/unistd.h> /* 0 = no checking 1 = put_count checking 2 = verbose put_count checking */ #define AUDIT_DEBUG 0 /* No syscall auditing will take place unless audit_enabled != 0. */ extern int audit_enabled; /* AUDIT_NAMES is the number of slots we reserve in the audit_context * for saving names from getname(). */ #define AUDIT_NAMES 20 /* AUDIT_NAMES_RESERVED is the number of slots we reserve in the * audit_context from being used for nameless inodes from * path_lookup. */ #define AUDIT_NAMES_RESERVED 7 /* At task start time, the audit_state is set in the audit_context using a per-task filter. At syscall entry, the audit_state is augmented by the syscall filter. */ enum audit_state { AUDIT_DISABLED, /* Do not create per-task audit_context. * No syscall-specific audit records can * be generated. */ AUDIT_SETUP_CONTEXT, /* Create the per-task audit_context, * but don't necessarily fill it in at * syscall entry time (i.e., filter * instead). */ AUDIT_BUILD_CONTEXT, /* Create the per-task audit_context, * and always fill it in at syscall * entry time. This makes a full * syscall record available if some * other part of the kernel decides it * should be recorded. */ AUDIT_RECORD_CONTEXT /* Create the per-task audit_context, * always fill it in at syscall entry * time, and always write out the audit * record at syscall exit time. */ }; /* When fs/namei.c:getname() is called, we store the pointer in name and * we don't let putname() free it (instead we free all of the saved * pointers at syscall exit time). * * Further, in fs/namei.c:path_lookup() we store the inode and device. */ struct audit_names { const char *name; unsigned long ino; dev_t dev; umode_t mode; uid_t uid; gid_t gid; dev_t rdev; unsigned flags; }; struct audit_aux_data { struct audit_aux_data *next; int type; }; #define AUDIT_AUX_IPCPERM 0 struct audit_aux_data_ipcctl { struct audit_aux_data d; struct ipc_perm p; unsigned long qbytes; uid_t uid; gid_t gid; mode_t mode; }; struct audit_aux_data_socketcall { struct audit_aux_data d; int nargs; unsigned long args[0]; }; struct audit_aux_data_sockaddr { struct audit_aux_data d; int len; char a[0]; }; struct audit_aux_data_path { struct audit_aux_data d; struct dentry *dentry; struct vfsmount *mnt; }; /* The per-task audit context. */ struct audit_context { int in_syscall; /* 1 if task is in a syscall */ enum audit_state state; unsigned int serial; /* serial number for record */ struct timespec ctime; /* time of syscall entry */ uid_t loginuid; /* login uid (identity) */ int major; /* syscall number */ unsigned long argv[4]; /* syscall arguments */ int return_valid; /* return code is valid */ long return_code;/* syscall return code */ int auditable; /* 1 if record should be written */ int name_count; struct audit_names names[AUDIT_NAMES]; struct dentry * pwd; struct vfsmount * pwdmnt; struct audit_context *previous; /* For nested syscalls */ struct audit_aux_data *aux; /* Save things to print about task_struct */ pid_t pid; uid_t uid, euid, suid, fsuid; gid_t gid, egid, sgid, fsgid; unsigned long personality; int arch; #if AUDIT_DEBUG int put_count; int ino_count; #endif }; /* Public API */ /* There are three lists of rules -- one to search at task creation * time, one to search at syscall entry time, and another to search at * syscall exit time. */ static struct list_head audit_filter_list[AUDIT_NR_FILTERS] = { LIST_HEAD_INIT(audit_filter_list[0]), LIST_HEAD_INIT(audit_filter_list[1]), LIST_HEAD_INIT(audit_filter_list[2]), LIST_HEAD_INIT(audit_filter_list[3]), LIST_HEAD_INIT(audit_filter_list[4]), #if AUDIT_NR_FILTERS != 5 #error Fix audit_filter_list initialiser #endif }; struct audit_entry { struct list_head list; struct rcu_head rcu; struct audit_rule rule; }; extern int audit_pid; /* Copy rule from user-space to kernel-space. Called from * audit_add_rule during AUDIT_ADD. */ static inline int audit_copy_rule(struct audit_rule *d, struct audit_rule *s) { int i; if (s->action != AUDIT_NEVER && s->action != AUDIT_POSSIBLE && s->action != AUDIT_ALWAYS) return -1; if (s->field_count < 0 || s->field_count > AUDIT_MAX_FIELDS) return -1; if ((s->flags & ~AUDIT_FILTER_PREPEND) >= AUDIT_NR_FILTERS) return -1; d->flags = s->flags; d->action = s->action; d->field_count = s->field_count; for (i = 0; i < d->field_count; i++) { d->fields[i] = s->fields[i]; d->values[i] = s->values[i]; } for (i = 0; i < AUDIT_BITMASK_SIZE; i++) d->mask[i] = s->mask[i]; return 0; } /* Check to see if two rules are identical. It is called from * audit_add_rule during AUDIT_ADD and * audit_del_rule during AUDIT_DEL. */ static inline int audit_compare_rule(struct audit_rule *a, struct audit_rule *b) { int i; if (a->flags != b->flags) return 1; if (a->action != b->action) return 1; if (a->field_count != b->field_count) return 1; for (i = 0; i < a->field_count; i++) { if (a->fields[i] != b->fields[i] || a->values[i] != b->values[i]) return 1; } for (i = 0; i < AUDIT_BITMASK_SIZE; i++) if (a->mask[i] != b->mask[i]) return 1; return 0; } /* Note that audit_add_rule and audit_del_rule are called via * audit_receive() in audit.c, and are protected by * audit_netlink_sem. */ static inline int audit_add_rule(struct audit_rule *rule, struct list_head *list) { struct audit_entry *entry; /* Do not use the _rcu iterator here, since this is the only * addition routine. */ list_for_each_entry(entry, list, list) { if (!audit_compare_rule(rule, &entry->rule)) { return -EEXIST; } } if (!(entry = kmalloc(sizeof(*entry), GFP_KERNEL))) return -ENOMEM; if (audit_copy_rule(&entry->rule, rule)) { kfree(entry); return -EINVAL; } if (entry->rule.flags & AUDIT_FILTER_PREPEND) { entry->rule.flags &= ~AUDIT_FILTER_PREPEND; list_add_rcu(&entry->list, list); } else { list_add_tail_rcu(&entry->list, list); } return 0; } static inline void audit_free_rule(struct rcu_head *head) { struct audit_entry *e = container_of(head, struct audit_entry, rcu); kfree(e); } /* Note that audit_add_rule and audit_del_rule are called via * audit_receive() in audit.c, and are protected by * audit_netlink_sem. */ static inline int audit_del_rule(struct audit_rule *rule, struct list_head *list) { struct audit_entry *e; /* Do not use the _rcu iterator here, since this is the only * deletion routine. */ list_for_each_entry(e, list, list) { if (!audit_compare_rule(rule, &e->rule)) { list_del_rcu(&e->list); call_rcu(&e->rcu, audit_free_rule); return 0; } } return -ENOENT; /* No matching rule */ } static int audit_list_rules(void *_dest) { int pid, seq; int *dest = _dest; struct audit_entry *entry; int i; pid = dest[0]; seq = dest[1]; kfree(dest); down(&audit_netlink_sem); /* The *_rcu iterators not needed here because we are always called with audit_netlink_sem held. */ for (i=0; i<AUDIT_NR_FILTERS; i++) { list_for_each_entry(entry, &audit_filter_list[i], list) audit_send_reply(pid, seq, AUDIT_LIST, 0, 1, &entry->rule, sizeof(entry->rule)); } audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0); up(&audit_netlink_sem); return 0; } int audit_receive_filter(int type, int pid, int uid, int seq, void *data, uid_t loginuid) { struct task_struct *tsk; int *dest; int err = 0; unsigned listnr; switch (type) { case AUDIT_LIST: /* We can't just spew out the rules here because we might fill * the available socket buffer space and deadlock waiting for * auditctl to read from it... which isn't ever going to * happen if we're actually running in the context of auditctl * trying to _send_ the stuff */ dest = kmalloc(2 * sizeof(int), GFP_KERNEL); if (!dest) return -ENOMEM; dest[0] = pid; dest[1] = seq; tsk = kthread_run(audit_list_rules, dest, "audit_list_rules"); if (IS_ERR(tsk)) { kfree(dest); err = PTR_ERR(tsk); } break; case AUDIT_ADD: listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND; if (listnr >= AUDIT_NR_FILTERS) return -EINVAL; err = audit_add_rule(data, &audit_filter_list[listnr]); if (!err) audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, "auid=%u added an audit rule\n", loginuid); break; case AUDIT_DEL: listnr =((struct audit_rule *)data)->flags & ~AUDIT_FILTER_PREPEND; if (listnr >= AUDIT_NR_FILTERS) return -EINVAL; err = audit_del_rule(data, &audit_filter_list[listnr]); if (!err) audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, "auid=%u removed an audit rule\n", loginuid); break; default: return -EINVAL; } return err; } /* Compare a task_struct with an audit_rule. Return 1 on match, 0 * otherwise. */ static int audit_filter_rules(struct task_struct *tsk, struct audit_rule *rule, struct audit_context *ctx, enum audit_state *state) { int i, j; for (i = 0; i < rule->field_count; i++) { u32 field = rule->fields[i] & ~AUDIT_NEGATE; u32 value = rule->values[i]; int result = 0; switch (field) { case AUDIT_PID: result = (tsk->pid == value); break; case AUDIT_UID: result = (tsk->uid == value); break; case AUDIT_EUID: result = (tsk->euid == value); break; case AUDIT_SUID: result = (tsk->suid == value); break; case AUDIT_FSUID: result = (tsk->fsuid == value); break; case AUDIT_GID: result = (tsk->gid == value); break; case AUDIT_EGID: result = (tsk->egid == value); break; case AUDIT_SGID: result = (tsk->sgid == value); break; case AUDIT_FSGID: result = (tsk->fsgid == value); break; case AUDIT_PERS: result = (tsk->personality == value); break; case AUDIT_ARCH: if (ctx) result = (ctx->arch == value); break; case AUDIT_EXIT: if (ctx && ctx->return_valid) result = (ctx->return_code == value); break; case AUDIT_SUCCESS: if (ctx && ctx->return_valid) { if (value) result = (ctx->return_valid == AUDITSC_SUCCESS); else result = (ctx->return_valid == AUDITSC_FAILURE); } break; case AUDIT_DEVMAJOR: if (ctx) { for (j = 0; j < ctx->name_count; j++) { if (MAJOR(ctx->names[j].dev)==value) { ++result; break; } } } break; case AUDIT_DEVMINOR: if (ctx) { for (j = 0; j < ctx->name_count; j++) { if (MINOR(ctx->names[j].dev)==value) { ++result; break; } } } break; case AUDIT_INODE: if (ctx) { for (j = 0; j < ctx->name_count; j++) { if (ctx->names[j].ino == value) { ++result; break; } } } break; case AUDIT_LOGINUID: result = 0; if (ctx) result = (ctx->loginuid == value); break; case AUDIT_ARG0: case AUDIT_ARG1: case AUDIT_ARG2: case AUDIT_ARG3: if (ctx) result = (ctx->argv[field-AUDIT_ARG0]==value); break; } if (rule->fields[i] & AUDIT_NEGATE) result = !result; if (!result) return 0; } switch (rule->action) { case AUDIT_NEVER: *state = AUDIT_DISABLED; break; case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT; break; case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break; } return 1; } /* At process creation time, we can determine if system-call auditing is * completely disabled for this task. Since we only have the task * structure at this point, we can only check uid and gid. */ static enum audit_state audit_filter_task(struct task_struct *tsk) { struct audit_entry *e; enum audit_state state; rcu_read_lock(); list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TASK], list) { if (audit_filter_rules(tsk, &e->rule, NULL, &state)) { rcu_read_unlock(); return state; } } rcu_read_unlock(); return AUDIT_BUILD_CONTEXT; } /* At syscall entry and exit time, this filter is called if the * audit_state is not low enough that auditing cannot take place, but is * also not high enough that we already know we have to write an audit * record (i.e., the state is AUDIT_SETUP_CONTEXT or AUDIT_BUILD_CONTEXT). */ static enum audit_state audit_filter_syscall(struct task_struct *tsk, struct audit_context *ctx, struct list_head *list) { struct audit_entry *e; enum audit_state state; if (audit_pid && tsk->tgid == audit_pid) return AUDIT_DISABLED; rcu_read_lock(); if (!list_empty(list)) { int word = AUDIT_WORD(ctx->major); int bit = AUDIT_BIT(ctx->major); list_for_each_entry_rcu(e, list, list) { if ((e->rule.mask[word] & bit) == bit && audit_filter_rules(tsk, &e->rule, ctx, &state)) { rcu_read_unlock(); return state; } } } rcu_read_unlock(); return AUDIT_BUILD_CONTEXT; } static int audit_filter_user_rules(struct netlink_skb_parms *cb, struct audit_rule *rule, enum audit_state *state) { int i; for (i = 0; i < rule->field_count; i++) { u32 field = rule->fields[i] & ~AUDIT_NEGATE; u32 value = rule->values[i]; int result = 0; switch (field) { case AUDIT_PID: result = (cb->creds.pid == value); break; case AUDIT_UID: result = (cb->creds.uid == value); break; case AUDIT_GID: result = (cb->creds.gid == value); break; case AUDIT_LOGINUID: result = (cb->loginuid == value); break; } if (rule->fields[i] & AUDIT_NEGATE) result = !result; if (!result) return 0; } switch (rule->action) { case AUDIT_NEVER: *state = AUDIT_DISABLED; break; case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT; break; case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break; } return 1; } int audit_filter_user(struct netlink_skb_parms *cb, int type) { struct audit_entry *e; enum audit_state state; int ret = 1; rcu_read_lock(); list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) { if (audit_filter_user_rules(cb, &e->rule, &state)) { if (state == AUDIT_DISABLED) ret = 0; break; } } rcu_read_unlock(); return ret; /* Audit by default */ } /* This should be called with task_lock() held. */ static inline struct audit_context *audit_get_context(struct task_struct *tsk, int return_valid, int return_code) { struct audit_context *context = tsk->audit_context; if (likely(!context)) return NULL; context->return_valid = return_valid; context->return_code = return_code; if (context->in_syscall && !context->auditable) { enum audit_state state; state = audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_EXIT]); if (state == AUDIT_RECORD_CONTEXT) context->auditable = 1; } context->pid = tsk->pid; context->uid = tsk->uid; context->gid = tsk->gid; context->euid = tsk->euid; context->suid = tsk->suid; context->fsuid = tsk->fsuid; context->egid = tsk->egid; context->sgid = tsk->sgid; context->fsgid = tsk->fsgid; context->personality = tsk->personality; tsk->audit_context = NULL; return context; } static inline void audit_free_names(struct audit_context *context) { int i; #if AUDIT_DEBUG == 2 if (context->auditable ||context->put_count + context->ino_count != context->name_count) { printk(KERN_ERR "audit.c:%d(:%d): major=%d in_syscall=%d" " name_count=%d put_count=%d" " ino_count=%d [NOT freeing]\n", __LINE__, context->serial, context->major, context->in_syscall, context->name_count, context->put_count, context->ino_count); for (i = 0; i < context->name_count; i++) printk(KERN_ERR "names[%d] = %p = %s\n", i, context->names[i].name, context->names[i].name); dump_stack(); return; } #endif #if AUDIT_DEBUG context->put_count = 0; context->ino_count = 0; #endif for (i = 0; i < context->name_count; i++) if (context->names[i].name) __putname(context->names[i].name); context->name_count = 0; if (context->pwd) dput(context->pwd); if (context->pwdmnt) mntput(context->pwdmnt); context->pwd = NULL; context->pwdmnt = NULL; } static inline void audit_free_aux(struct audit_context *context) { struct audit_aux_data *aux; while ((aux = context->aux)) { if (aux->type == AUDIT_AVC_PATH) { struct audit_aux_data_path *axi = (void *)aux; dput(axi->dentry); mntput(axi->mnt); } context->aux = aux->next; kfree(aux); } } static inline void audit_zero_context(struct audit_context *context, enum audit_state state) { uid_t loginuid = context->loginuid; memset(context, 0, sizeof(*context)); context->state = state; context->loginuid = loginuid; } static inline struct audit_context *audit_alloc_context(enum audit_state state) { struct audit_context *context; if (!(context = kmalloc(sizeof(*context), GFP_KERNEL))) return NULL; audit_zero_context(context, state); return context; } /* Filter on the task information and allocate a per-task audit context * if necessary. Doing so turns on system call auditing for the * specified task. This is called from copy_process, so no lock is * needed. */ int audit_alloc(struct task_struct *tsk) { struct audit_context *context; enum audit_state state; if (likely(!audit_enabled)) return 0; /* Return if not auditing. */ state = audit_filter_task(tsk); if (likely(state == AUDIT_DISABLED)) return 0; if (!(context = audit_alloc_context(state))) { audit_log_lost("out of memory in audit_alloc"); return -ENOMEM; } /* Preserve login uid */ context->loginuid = -1; if (current->audit_context) context->loginuid = current->audit_context->loginuid; tsk->audit_context = context; set_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT); return 0; } static inline void audit_free_context(struct audit_context *context) { struct audit_context *previous; int count = 0; do { previous = context->previous; if (previous || (count && count < 10)) { ++count; printk(KERN_ERR "audit(:%d): major=%d name_count=%d:" " freeing multiple contexts (%d)\n", context->serial, context->major, context->name_count, count); } audit_free_names(context); audit_free_aux(context); kfree(context); context = previous; } while (context); if (count >= 10) printk(KERN_ERR "audit: freed %d contexts\n", count); } static void audit_log_task_info(struct audit_buffer *ab) { char name[sizeof(current->comm)]; struct mm_struct *mm = current->mm; struct vm_area_struct *vma; get_task_comm(name, current); audit_log_format(ab, " comm="); audit_log_untrustedstring(ab, name); if (!mm) return; down_read(&mm->mmap_sem); vma = mm->mmap; while (vma) { if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file) { audit_log_d_path(ab, "exe=", vma->vm_file->f_dentry, vma->vm_file->f_vfsmnt); break; } vma = vma->vm_next; } up_read(&mm->mmap_sem); } static void audit_log_exit(struct audit_context *context, unsigned int gfp_mask) { int i; struct audit_buffer *ab; struct audit_aux_data *aux; ab = audit_log_start(context, gfp_mask, AUDIT_SYSCALL); if (!ab) return; /* audit_panic has been called */ audit_log_format(ab, "arch=%x syscall=%d", context->arch, context->major); if (context->personality != PER_LINUX) audit_log_format(ab, " per=%lx", context->personality); if (context->return_valid) audit_log_format(ab, " success=%s exit=%ld", (context->return_valid==AUDITSC_SUCCESS)?"yes":"no", context->return_code); audit_log_format(ab, " a0=%lx a1=%lx a2=%lx a3=%lx items=%d" " pid=%d auid=%u uid=%u gid=%u" " euid=%u suid=%u fsuid=%u" " egid=%u sgid=%u fsgid=%u", context->argv[0], context->argv[1], context->argv[2], context->argv[3], context->name_count, context->pid, context->loginuid, context->uid, context->gid, context->euid, context->suid, context->fsuid, context->egid, context->sgid, context->fsgid); audit_log_task_info(ab); audit_log_end(ab); for (aux = context->aux; aux; aux = aux->next) { ab = audit_log_start(context, GFP_KERNEL, aux->type); if (!ab) continue; /* audit_panic has been called */ switch (aux->type) { case AUDIT_IPC: { struct audit_aux_data_ipcctl *axi = (void *)aux; audit_log_format(ab, " qbytes=%lx iuid=%u igid=%u mode=%x", axi->qbytes, axi->uid, axi->gid, axi->mode); break; } case AUDIT_SOCKETCALL: { int i; struct audit_aux_data_socketcall *axs = (void *)aux; audit_log_format(ab, "nargs=%d", axs->nargs); for (i=0; i<axs->nargs; i++) audit_log_format(ab, " a%d=%lx", i, axs->args[i]); break; } case AUDIT_SOCKADDR: { struct audit_aux_data_sockaddr *axs = (void *)aux; audit_log_format(ab, "saddr="); audit_log_hex(ab, axs->a, axs->len); break; } case AUDIT_AVC_PATH: { struct audit_aux_data_path *axi = (void *)aux; audit_log_d_path(ab, "path=", axi->dentry, axi->mnt); break; } } audit_log_end(ab); } if (context->pwd && context->pwdmnt) { ab = audit_log_start(context, GFP_KERNEL, AUDIT_CWD); if (ab) { audit_log_d_path(ab, "cwd=", context->pwd, context->pwdmnt); audit_log_end(ab); } } for (i = 0; i < context->name_count; i++) { ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH); if (!ab) continue; /* audit_panic has been called */ audit_log_format(ab, "item=%d", i); if (context->names[i].name) { audit_log_format(ab, " name="); audit_log_untrustedstring(ab, context->names[i].name); } audit_log_format(ab, " flags=%x\n", context->names[i].flags); if (context->names[i].ino != (unsigned long)-1) audit_log_format(ab, " inode=%lu dev=%02x:%02x mode=%#o" " ouid=%u ogid=%u rdev=%02x:%02x", context->names[i].ino, MAJOR(context->names[i].dev), MINOR(context->names[i].dev), context->names[i].mode, context->names[i].uid, context->names[i].gid, MAJOR(context->names[i].rdev), MINOR(context->names[i].rdev)); audit_log_end(ab); } } /* Free a per-task audit context. Called from copy_process and * __put_task_struct. */ void audit_free(struct task_struct *tsk) { struct audit_context *context; task_lock(tsk); context = audit_get_context(tsk, 0, 0); task_unlock(tsk); if (likely(!context)) return; /* Check for system calls that do not go through the exit * function (e.g., exit_group), then free context block. * We use GFP_ATOMIC here because we might be doing this * in the context of the idle thread */ if (context->in_syscall && context->auditable) audit_log_exit(context, GFP_ATOMIC); audit_free_context(context); } /* Fill in audit context at syscall entry. This only happens if the * audit context was created when the task was created and the state or * filters demand the audit context be built. If the state from the * per-task filter or from the per-syscall filter is AUDIT_RECORD_CONTEXT, * then the record will be written at syscall exit time (otherwise, it * will only be written if another part of the kernel requests that it * be written). */ void audit_syscall_entry(struct task_struct *tsk, int arch, int major, unsigned long a1, unsigned long a2, unsigned long a3, unsigned long a4) { struct audit_context *context = tsk->audit_context; enum audit_state state; BUG_ON(!context); /* This happens only on certain architectures that make system * calls in kernel_thread via the entry.S interface, instead of * with direct calls. (If you are porting to a new * architecture, hitting this condition can indicate that you * got the _exit/_leave calls backward in entry.S.) * * i386 no * x86_64 no * ppc64 yes (see arch/ppc64/kernel/misc.S) * * This also happens with vm86 emulation in a non-nested manner * (entries without exits), so this case must be caught. */ if (context->in_syscall) { struct audit_context *newctx; #if defined(__NR_vm86) && defined(__NR_vm86old) /* vm86 mode should only be entered once */ if (major == __NR_vm86 || major == __NR_vm86old) return; #endif #if AUDIT_DEBUG printk(KERN_ERR "audit(:%d) pid=%d in syscall=%d;" " entering syscall=%d\n", context->serial, tsk->pid, context->major, major); #endif newctx = audit_alloc_context(context->state); if (newctx) { newctx->previous = context; context = newctx; tsk->audit_context = newctx; } else { /* If we can't alloc a new context, the best we * can do is to leak memory (any pending putname * will be lost). The only other alternative is * to abandon auditing. */ audit_zero_context(context, context->state); } } BUG_ON(context->in_syscall || context->name_count); if (!audit_enabled) return; context->arch = arch; context->major = major; context->argv[0] = a1; context->argv[1] = a2; context->argv[2] = a3; context->argv[3] = a4; state = context->state; if (state == AUDIT_SETUP_CONTEXT || state == AUDIT_BUILD_CONTEXT) state = audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_ENTRY]); if (likely(state == AUDIT_DISABLED)) return; context->serial = 0; context->ctime = CURRENT_TIME; context->in_syscall = 1; context->auditable = !!(state == AUDIT_RECORD_CONTEXT); } /* Tear down after system call. If the audit context has been marked as * auditable (either because of the AUDIT_RECORD_CONTEXT state from * filtering, or because some other part of the kernel write an audit * message), then write out the syscall information. In call cases, * free the names stored from getname(). */ void audit_syscall_exit(struct task_struct *tsk, int valid, long return_code) { struct audit_context *context; get_task_struct(tsk); task_lock(tsk); context = audit_get_context(tsk, valid, return_code); task_unlock(tsk); /* Not having a context here is ok, since the parent may have * called __put_task_struct. */ if (likely(!context)) goto out; if (context->in_syscall && context->auditable) audit_log_exit(context, GFP_KERNEL); context->in_syscall = 0; context->auditable = 0; if (context->previous) { struct audit_context *new_context = context->previous; context->previous = NULL; audit_free_context(context); tsk->audit_context = new_context; } else { audit_free_names(context); audit_free_aux(context); tsk->audit_context = context; } out: put_task_struct(tsk); } /* Add a name to the list. Called from fs/namei.c:getname(). */ void audit_getname(const char *name) { struct audit_context *context = current->audit_context; if (!context || IS_ERR(name) || !name) return; if (!context->in_syscall) { #if AUDIT_DEBUG == 2 printk(KERN_ERR "%s:%d(:%d): ignoring getname(%p)\n", __FILE__, __LINE__, context->serial, name); dump_stack(); #endif return; } BUG_ON(context->name_count >= AUDIT_NAMES); context->names[context->name_count].name = name; context->names[context->name_count].ino = (unsigned long)-1; ++context->name_count; if (!context->pwd) { read_lock(¤t->fs->lock); context->pwd = dget(current->fs->pwd); context->pwdmnt = mntget(current->fs->pwdmnt); read_unlock(¤t->fs->lock); } } /* Intercept a putname request. Called from * include/linux/fs.h:putname(). If we have stored the name from * getname in the audit context, then we delay the putname until syscall * exit. */ void audit_putname(const char *name) { struct audit_context *context = current->audit_context; BUG_ON(!context); if (!context->in_syscall) { #if AUDIT_DEBUG == 2 printk(KERN_ERR "%s:%d(:%d): __putname(%p)\n", __FILE__, __LINE__, context->serial, name); if (context->name_count) { int i; for (i = 0; i < context->name_count; i++) printk(KERN_ERR "name[%d] = %p = %s\n", i, context->names[i].name, context->names[i].name); } #endif __putname(name); } #if AUDIT_DEBUG else { ++context->put_count; if (context->put_count > context->name_count) { printk(KERN_ERR "%s:%d(:%d): major=%d" " in_syscall=%d putname(%p) name_count=%d" " put_count=%d\n", __FILE__, __LINE__, context->serial, context->major, context->in_syscall, name, context->name_count, context->put_count); dump_stack(); } } #endif } /* Store the inode and device from a lookup. Called from * fs/namei.c:path_lookup(). */ void audit_inode(const char *name, const struct inode *inode, unsigned flags) { int idx; struct audit_context *context = current->audit_context; if (!context->in_syscall) return; if (context->name_count && context->names[context->name_count-1].name && context->names[context->name_count-1].name == name) idx = context->name_count - 1; else if (context->name_count > 1 && context->names[context->name_count-2].name && context->names[context->name_count-2].name == name) idx = context->name_count - 2; else { /* FIXME: how much do we care about inodes that have no * associated name? */ if (context->name_count >= AUDIT_NAMES - AUDIT_NAMES_RESERVED) return; idx = context->name_count++; context->names[idx].name = NULL; #if AUDIT_DEBUG ++context->ino_count; #endif } context->names[idx].flags = flags; context->names[idx].ino = inode->i_ino; context->names[idx].dev = inode->i_sb->s_dev; context->names[idx].mode = inode->i_mode; context->names[idx].uid = inode->i_uid; context->names[idx].gid = inode->i_gid; context->names[idx].rdev = inode->i_rdev; } void auditsc_get_stamp(struct audit_context *ctx, struct timespec *t, unsigned int *serial) { if (!ctx->serial) ctx->serial = audit_serial(); t->tv_sec = ctx->ctime.tv_sec; t->tv_nsec = ctx->ctime.tv_nsec; *serial = ctx->serial; ctx->auditable = 1; } int audit_set_loginuid(struct task_struct *task, uid_t loginuid) { if (task->audit_context) { struct audit_buffer *ab; ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN); if (ab) { audit_log_format(ab, "login pid=%d uid=%u " "old auid=%u new auid=%u", task->pid, task->uid, task->audit_context->loginuid, loginuid); audit_log_end(ab); } task->audit_context->loginuid = loginuid; } return 0; } uid_t audit_get_loginuid(struct audit_context *ctx) { return ctx ? ctx->loginuid : -1; } int audit_ipc_perms(unsigned long qbytes, uid_t uid, gid_t gid, mode_t mode) { struct audit_aux_data_ipcctl *ax; struct audit_context *context = current->audit_context; if (likely(!context)) return 0; ax = kmalloc(sizeof(*ax), GFP_KERNEL); if (!ax) return -ENOMEM; ax->qbytes = qbytes; ax->uid = uid; ax->gid = gid; ax->mode = mode; ax->d.type = AUDIT_IPC; ax->d.next = context->aux; context->aux = (void *)ax; return 0; } int audit_socketcall(int nargs, unsigned long *args) { struct audit_aux_data_socketcall *ax; struct audit_context *context = current->audit_context; if (likely(!context)) return 0; ax = kmalloc(sizeof(*ax) + nargs * sizeof(unsigned long), GFP_KERNEL); if (!ax) return -ENOMEM; ax->nargs = nargs; memcpy(ax->args, args, nargs * sizeof(unsigned long)); ax->d.type = AUDIT_SOCKETCALL; ax->d.next = context->aux; context->aux = (void *)ax; return 0; } int audit_sockaddr(int len, void *a) { struct audit_aux_data_sockaddr *ax; struct audit_context *context = current->audit_context; if (likely(!context)) return 0; ax = kmalloc(sizeof(*ax) + len, GFP_KERNEL); if (!ax) return -ENOMEM; ax->len = len; memcpy(ax->a, a, len); ax->d.type = AUDIT_SOCKADDR; ax->d.next = context->aux; context->aux = (void *)ax; return 0; } int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt) { struct audit_aux_data_path *ax; struct audit_context *context = current->audit_context; if (likely(!context)) return 0; ax = kmalloc(sizeof(*ax), GFP_ATOMIC); if (!ax) return -ENOMEM; ax->dentry = dget(dentry); ax->mnt = mntget(mnt); ax->d.type = AUDIT_AVC_PATH; ax->d.next = context->aux; context->aux = (void *)ax; return 0; } void audit_signal_info(int sig, struct task_struct *t) { extern pid_t audit_sig_pid; extern uid_t audit_sig_uid; if (unlikely(audit_pid && t->tgid == audit_pid)) { if (sig == SIGTERM || sig == SIGHUP) { struct audit_context *ctx = current->audit_context; audit_sig_pid = current->pid; if (ctx) audit_sig_uid = ctx->loginuid; else audit_sig_uid = current->uid; } } }