AUDIT: Avoid log pollution by untrusted strings.

We log strings from userspace, such as arguments to open(). These could
be formatted to contain \n followed by fake audit log entries. Provide
a function for logging such strings, which gives a hex dump when the
string contains anything but basic printable ASCII characters. Use it
for logging filenames.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 3628f7cfb178..9b77992c4888 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -174,11 +174,15 @@ extern void		    audit_log_format(struct audit_buffer *ab,
                                              const char *fmt, ...)
                             __attribute__((format(printf,2,3)));
 extern void                 audit_log_end(struct audit_buffer *ab);
+extern void                 audit_log_hex(struct audit_buffer *ab,
+                                          const unsigned char *buf,
+                                          size_t len);
+extern void                 audit_log_untrustedstring(struct audit_buffer *ab,
+                                                      const char *string);
 extern void                 audit_log_d_path(struct audit_buffer *ab,
                                              const char *prefix,
                                              struct dentry *dentry,
                                              struct vfsmount *vfsmnt);
-
                                 /* Private API (for auditsc.c only) */
 extern void                 audit_send_reply(int pid, int seq, int type,
                                              int done, int multi,
@@ -190,6 +194,8 @@ extern void		    audit_log_lost(const char *message);
 #define audit_log_vformat(b,f,a) do { ; } while (0)
 #define audit_log_format(b,f,...) do { ; } while (0)
 #define audit_log_end(b) do { ; } while (0)
+#define audit_log_hex(a,b,l) do { ; } while (0)
+#define audit_log_untrustedstring(a,s) do { ; } while (0)
 #define audit_log_d_path(b,p,d,v) do { ; } while (0)
 #endif
 #endif