Bounds checking :)

CMakeLists.txt

@@ -2,6 +2,8 @@ cmake_minimum_required(VERSION 3.8..3.22)
 
 project(minitar LANGUAGES C VERSION 1.3.0)
 
+option(MINITAR_IGNORE_UNSUPPORTED_TYPES "Skip past entries that have unsupported types instead of panicking" OFF)
+
 set(SOURCES
     src/tar.c
     src/util.c
@@ -9,6 +11,10 @@ set(SOURCES
 
 add_library(minitar STATIC ${SOURCES})
 
+if(MINITAR_IGNORE_UNSUPPORTED_TYPES)
+target_compile_definitions(minitar PRIVATE MINITAR_IGNORE_UNSUPPORTED_TYPES)
+endif()
+
 target_include_directories(minitar PUBLIC ${CMAKE_CURRENT_LIST_DIR}) # for minitar.h
 
 set_target_properties(minitar PROPERTIES OUTPUT_NAME mtar)

README.md

@@ -118,7 +118,7 @@ This enum lists all supported file types:
 
 `MTAR_DIRECTORY`: Directories
 
-Other file types supported in tar archives, such as block/character devices, FIFOs, or symlinks, are not supported and minitar will throw an error when encountering one of them.
+Other file types supported in tar archives, such as block/character devices, FIFOs, or symlinks, are not supported and minitar will throw an error when encountering one of them. This behavior can be controlled by passing `-DMINITAR_IGNORE_UNSUPPORTED_TYPES=ON` to CMake when configuring, which will make minitar silently ignore such entries instead of panicking.
 
 ### minitar_entry_metadata
 `struct minitar_entry_metadata`

src/util.c

@@ -1,5 +1,6 @@
 #include "minitar.h"
 #include "tar.h"
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -93,6 +94,7 @@ static size_t minitar_align_down_to_block_size(size_t size)
 static char* minitar_static_dup(const char* str, size_t size)
 {
     static char result[1024];
+    assert(size < 1024);
     memcpy(result, str, size);
     result[size] = 0;
     return result;
@@ -168,9 +170,13 @@ void minitar_parse_metadata_from_tar_header(const struct tar_header* hdr, struct
 
 int minitar_validate_header(const struct tar_header* hdr)
 {
+#ifdef MINITAR_IGNORE_UNSUPPORTED_TYPES
+    if (hdr->typeflag != '\0' && hdr->typeflag != '0' && hdr->typeflag != '5') return 0;
+#else
     if (hdr->typeflag != '\0' && hdr->typeflag != '0' && hdr->typeflag != '1' && hdr->typeflag != '2' &&
         hdr->typeflag != '3' && hdr->typeflag != '4' && hdr->typeflag != '5' && hdr->typeflag != '6')
         return 0;
+#endif
     return !strncmp(hdr->magic, "ustar", 5);
 }