diff --git a/src/util-magic.c b/src/util-magic.c
index bad15fbe5e..0fbb6994ae 100644
--- a/src/util-magic.c
+++ b/src/util-magic.c
@@ -103,7 +103,7 @@ error:
  *
  *  \retval result pointer to null terminated string
  */
-char *MagicGlobalLookup(uint8_t *buf, uint32_t buflen)
+char *MagicGlobalLookup(const uint8_t *buf, uint32_t buflen)
 {
     const char *result = NULL;
     char *magic = NULL;
@@ -132,7 +132,7 @@ char *MagicGlobalLookup(uint8_t *buf, uint32_t buflen)
  *
  *  \retval result pointer to null terminated string
  */
-char *MagicThreadLookup(magic_t *ctx, uint8_t *buf, uint32_t buflen)
+char *MagicThreadLookup(magic_t *ctx, const uint8_t *buf, uint32_t buflen)
 {
     const char *result = NULL;
     char *magic = NULL;
diff --git a/src/util-magic.h b/src/util-magic.h
index 0efdbd147b..85b72d1b15 100644
--- a/src/util-magic.h
+++ b/src/util-magic.h
@@ -28,8 +28,8 @@
 
 int MagicInit(void);
 void MagicDeinit(void);
-char *MagicGlobalLookup(uint8_t *, uint32_t);
-char *MagicThreadLookup(magic_t *, uint8_t *, uint32_t);
+char *MagicGlobalLookup(const uint8_t *, uint32_t);
+char *MagicThreadLookup(magic_t *, const uint8_t *, uint32_t);
 void MagicRegisterTests(void);
 
 #endif /* __UTIL_MAGIC_H__ */