From b24a30a7305418ff138ff51776fc555ec57c011a Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 30 Apr 2013 15:30:32 -0400 Subject: audit: fix event coverage of AUDIT_ANOM_LINK The userspace audit tools didn't like the existing formatting of the AUDIT_ANOM_LINK event. It needed to be expanded to emit an AUDIT_PATH event as well, so this implements the change. The bulk of the patch is moving code out of auditsc.c into audit.c and audit.h for general use. It expands audit_log_name to include an optional "struct path" argument for the simple case of just needing to report a pathname. This also makes audit_log_task_info available when syscall auditing is not enabled, since it is needed in either case for process details. Signed-off-by: Kees Cook Reported-by: Steve Grubb --- kernel/audit.c | 244 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 236 insertions(+), 8 deletions(-) (limited to 'kernel/audit.c') diff --git a/kernel/audit.c b/kernel/audit.c index d308723d22da..8cc580316948 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -50,6 +50,7 @@ #include #include #include +#include #include @@ -1393,6 +1394,224 @@ void audit_log_key(struct audit_buffer *ab, char *key) audit_log_format(ab, "(null)"); } +void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap) +{ + int i; + + audit_log_format(ab, " %s=", prefix); + CAP_FOR_EACH_U32(i) { + audit_log_format(ab, "%08x", + cap->cap[(_KERNEL_CAPABILITY_U32S-1) - i]); + } +} + +void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name) +{ + kernel_cap_t *perm = &name->fcap.permitted; + kernel_cap_t *inh = &name->fcap.inheritable; + int log = 0; + + if (!cap_isclear(*perm)) { + audit_log_cap(ab, "cap_fp", perm); + log = 1; + } + if (!cap_isclear(*inh)) { + audit_log_cap(ab, "cap_fi", inh); + log = 1; + } + + if (log) + audit_log_format(ab, " cap_fe=%d cap_fver=%x", + name->fcap.fE, name->fcap_ver); +} + +static inline int audit_copy_fcaps(struct audit_names *name, + const struct dentry *dentry) +{ + struct cpu_vfs_cap_data caps; + int rc; + + if (!dentry) + return 0; + + rc = get_vfs_caps_from_disk(dentry, &caps); + if (rc) + return rc; + + name->fcap.permitted = caps.permitted; + name->fcap.inheritable = caps.inheritable; + name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE); + name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >> + VFS_CAP_REVISION_SHIFT; + + return 0; +} + +/* Copy inode data into an audit_names. */ +void audit_copy_inode(struct audit_names *name, const struct dentry *dentry, + const struct inode *inode) +{ + name->ino = inode->i_ino; + name->dev = inode->i_sb->s_dev; + name->mode = inode->i_mode; + name->uid = inode->i_uid; + name->gid = inode->i_gid; + name->rdev = inode->i_rdev; + security_inode_getsecid(inode, &name->osid); + audit_copy_fcaps(name, dentry); +} + +/** + * audit_log_name - produce AUDIT_PATH record from struct audit_names + * @context: audit_context for the task + * @n: audit_names structure with reportable details + * @path: optional path to report instead of audit_names->name + * @record_num: record number to report when handling a list of names + * @call_panic: optional pointer to int that will be updated if secid fails + */ +void audit_log_name(struct audit_context *context, struct audit_names *n, + struct path *path, int record_num, int *call_panic) +{ + struct audit_buffer *ab; + ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH); + if (!ab) + return; + + audit_log_format(ab, "item=%d", record_num); + + if (path) + audit_log_d_path(ab, " name=", path); + else if (n->name) { + switch (n->name_len) { + case AUDIT_NAME_FULL: + /* log the full path */ + audit_log_format(ab, " name="); + audit_log_untrustedstring(ab, n->name->name); + break; + case 0: + /* name was specified as a relative path and the + * directory component is the cwd */ + audit_log_d_path(ab, " name=", &context->pwd); + break; + default: + /* log the name's directory component */ + audit_log_format(ab, " name="); + audit_log_n_untrustedstring(ab, n->name->name, + n->name_len); + } + } else + audit_log_format(ab, " name=(null)"); + + if (n->ino != (unsigned long)-1) { + audit_log_format(ab, " inode=%lu" + " dev=%02x:%02x mode=%#ho" + " ouid=%u ogid=%u rdev=%02x:%02x", + n->ino, + MAJOR(n->dev), + MINOR(n->dev), + n->mode, + from_kuid(&init_user_ns, n->uid), + from_kgid(&init_user_ns, n->gid), + MAJOR(n->rdev), + MINOR(n->rdev)); + } + if (n->osid != 0) { + char *ctx = NULL; + u32 len; + if (security_secid_to_secctx( + n->osid, &ctx, &len)) { + audit_log_format(ab, " osid=%u", n->osid); + if (call_panic) + *call_panic = 2; + } else { + audit_log_format(ab, " obj=%s", ctx); + security_release_secctx(ctx, len); + } + } + + audit_log_fcaps(ab, n); + audit_log_end(ab); +} + +int audit_log_task_context(struct audit_buffer *ab) +{ + char *ctx = NULL; + unsigned len; + int error; + u32 sid; + + security_task_getsecid(current, &sid); + if (!sid) + return 0; + + error = security_secid_to_secctx(sid, &ctx, &len); + if (error) { + if (error != -EINVAL) + goto error_path; + return 0; + } + + audit_log_format(ab, " subj=%s", ctx); + security_release_secctx(ctx, len); + return 0; + +error_path: + audit_panic("error in audit_log_task_context"); + return error; +} +EXPORT_SYMBOL(audit_log_task_context); + +void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk) +{ + const struct cred *cred; + char name[sizeof(tsk->comm)]; + struct mm_struct *mm = tsk->mm; + char *tty; + + if (!ab) + return; + + /* tsk == current */ + cred = current_cred(); + + spin_lock_irq(&tsk->sighand->siglock); + if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name) + tty = tsk->signal->tty->name; + else + tty = "(none)"; + spin_unlock_irq(&tsk->sighand->siglock); + + audit_log_format(ab, + " ppid=%ld pid=%d auid=%u uid=%u gid=%u" + " euid=%u suid=%u fsuid=%u" + " egid=%u sgid=%u fsgid=%u ses=%u tty=%s", + sys_getppid(), + tsk->pid, + from_kuid(&init_user_ns, audit_get_loginuid(tsk)), + from_kuid(&init_user_ns, cred->uid), + from_kgid(&init_user_ns, cred->gid), + from_kuid(&init_user_ns, cred->euid), + from_kuid(&init_user_ns, cred->suid), + from_kuid(&init_user_ns, cred->fsuid), + from_kgid(&init_user_ns, cred->egid), + from_kgid(&init_user_ns, cred->sgid), + from_kgid(&init_user_ns, cred->fsgid), + audit_get_sessionid(tsk), tty); + + get_task_comm(name, tsk); + audit_log_format(ab, " comm="); + audit_log_untrustedstring(ab, name); + + if (mm) { + down_read(&mm->mmap_sem); + if (mm->exe_file) + audit_log_d_path(ab, " exe=", &mm->exe_file->f_path); + up_read(&mm->mmap_sem); + } + audit_log_task_context(ab); +} +EXPORT_SYMBOL(audit_log_task_info); + /** * audit_log_link_denied - report a link restriction denial * @operation: specific link opreation @@ -1401,19 +1620,28 @@ void audit_log_key(struct audit_buffer *ab, char *key) void audit_log_link_denied(const char *operation, struct path *link) { struct audit_buffer *ab; + struct audit_names *name; + + name = kzalloc(sizeof(*name), GFP_NOFS); + if (!name) + return; + /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */ ab = audit_log_start(current->audit_context, GFP_KERNEL, AUDIT_ANOM_LINK); if (!ab) - return; - audit_log_format(ab, "op=%s action=denied", operation); - audit_log_format(ab, " pid=%d comm=", current->pid); - audit_log_untrustedstring(ab, current->comm); - audit_log_d_path(ab, " path=", link); - audit_log_format(ab, " dev="); - audit_log_untrustedstring(ab, link->dentry->d_inode->i_sb->s_id); - audit_log_format(ab, " ino=%lu", link->dentry->d_inode->i_ino); + goto out; + audit_log_format(ab, "op=%s", operation); + audit_log_task_info(ab, current); + audit_log_format(ab, " res=0"); audit_log_end(ab); + + /* Generate AUDIT_PATH record with object. */ + name->type = AUDIT_TYPE_NORMAL; + audit_copy_inode(name, link->dentry, link->dentry->d_inode); + audit_log_name(current->audit_context, name, link, 0, NULL); +out: + kfree(name); } /** -- cgit v1.2.3