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 <keescook@chromium.org>
Reported-by: Steve Grubb <sgrubb@redhat.com>
diff --git a/kernel/audit.c b/kernel/audit.c
index d308723..8cc5803 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -50,6 +50,7 @@
#include <linux/err.h>
#include <linux/kthread.h>
#include <linux/kernel.h>
+#include <linux/syscalls.h>
#include <linux/audit.h>
@@ -1393,6 +1394,224 @@
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_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);
}
/**