[RAR5] FAIL if the decode table is > 2^16

diff --git a/Makefile.am b/Makefile.am
index a0a5a44a11c1346b41f058aaadf4d813f59f1cb3..faced2fc22c17c541d486e762fcdeb53362ca408 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -542,6 +542,7 @@ libarchive_test_SOURCES= \
        libarchive/test/test_read_format_rar_invalid1.c \
        libarchive/test/test_read_format_rar_overflow.c \
        libarchive/test/test_read_format_rar5.c \
+       libarchive/test/test_read_format_rar5_bad_tables.c \
        libarchive/test/test_read_format_rar5_loop_bug.c \
        libarchive/test/test_read_format_raw.c \
        libarchive/test/test_read_format_tar.c \
@@ -1008,6 +1009,7 @@ libarchive_test_EXTRA_DIST=\
        libarchive/test/test_read_format_rar5_block_size_is_too_small.rar.uu \
        libarchive/test/test_read_format_rar5_decode_number_out_of_bounds_read.rar.uu \
        libarchive/test/test_read_format_rar5_window_buf_and_size_desync.rar.uu \
+       libarchive/test/test_read_format_rar5_bad_tables.rar.uu \
        libarchive/test/test_read_format_rar5_bad_window_sz_in_mltarc_file.rar.uu \
        libarchive/test/test_read_format_rar5_data_ready_pointer_leak.rar.uu \
        libarchive/test/test_read_format_raw.bufr.uu \

diff --git a/libarchive/archive_read_support_format_rar5.c b/libarchive/archive_read_support_format_rar5.c
index 63dd97b3008a9361802e349b1ae9bf7855668c18..c699ddae788b5428f4a327667e1a0ef0701c9ca4 100644 (file)
--- a/libarchive/archive_read_support_format_rar5.c
+++ b/libarchive/archive_read_support_format_rar5.c
@@ -2647,6 +2647,15 @@ static int create_decode_tables(uint8_t* bit_length,
                upper_limit <<= 1;
        }
 
+       /* Verify the code-length distribution is not over-subscribed.
+        * After the loop above, upper_limit == sum(lc[i] * 2^(16-i)).
+        * For a valid prefix-free code this must be <= 2^16 = 65536.
+        * An over-subscribed table (> 65536) cannot produce a valid
+        * decode table and must be rejected. */
+       if(upper_limit > 65536) {
+               return ARCHIVE_FAILED;
+       }
+
        memcpy(decode_pos_clone, table->decode_pos, sizeof(decode_pos_clone));
 
        for(i = 0; i < size; i++) {

diff --git a/libarchive/test/CMakeLists.txt b/libarchive/test/CMakeLists.txt
index fb9bcdc0d50e8d39ec8a13fc32c817312e07a7f6..7bb8d4658802d778266309bb44fe92458393345d 100644 (file)
--- a/libarchive/test/CMakeLists.txt
+++ b/libarchive/test/CMakeLists.txt
@@ -176,6 +176,7 @@ IF(ENABLE_TEST)
     test_read_format_rar_filter.c
     test_read_format_rar_overflow.c
     test_read_format_rar5.c
+    test_read_format_rar5_bad_tables.c
     test_read_format_rar5_loop_bug.c
     test_read_format_raw.c
     test_read_format_tar.c

diff --git a/libarchive/test/test_read_format_rar5_bad_tables.c b/libarchive/test/test_read_format_rar5_bad_tables.c
new file mode 100644 (file)
index 0000000..38f4778
--- /dev/null
+++ b/libarchive/test/test_read_format_rar5_bad_tables.c
@@ -0,0 +1,64 @@
+/*-
+ * Copyright (c) 2026 Tim Kientzle
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "test.h"
+
+/*
+ * The reference archive contains one compressed entry whose HUFF_BC
+ * meta-table has all 20 nibbles set to bit-length 1.  This is an
+ * over-subscribed Huffman table (Kraft sum = 10 >> 1), which
+ * create_decode_tables() must reject.  Reading the entry data must
+ * therefore fail, not succeed.
+ */
+DEFINE_TEST(test_read_format_rar5_bad_tables)
+{
+       const char *reffile = "test_read_format_rar5_bad_tables.rar";
+       struct archive_entry *ae;
+       struct archive *a;
+       const void *buf;
+       size_t size;
+       la_int64_t offset;
+       int r;
+
+       extract_reference_file(reffile);
+       assert((a = archive_read_new()) != NULL);
+       assertEqualIntA(a, ARCHIVE_OK, archive_read_support_filter_all(a));
+       assertEqualIntA(a, ARCHIVE_OK, archive_read_support_format_all(a));
+       assertEqualIntA(a, ARCHIVE_OK,
+           archive_read_open_filename(a, reffile, 10240));
+
+       /* The file header is valid; the bad data is in the compressed block. */
+       assertEqualIntA(a, ARCHIVE_OK, archive_read_next_header(a, &ae));
+
+       /* Reading must fail because the meta-table is over-subscribed.
+        * TODO: Investigate whether ARCHIVE_FAILED is achievable here
+        * instead of ARCHIVE_FATAL, which would allow the caller to skip
+        * to a subsequent valid entry.  That would also require expanding
+        * the reference archive to include a valid entry after the bad one. */
+       assertEqualIntA(a, ARCHIVE_FATAL,
+           archive_read_data_block(a, &buf, &size, &offset));
+
+       assertEqualIntA(a, ARCHIVE_OK, archive_read_close(a));
+       assertEqualInt(ARCHIVE_OK, archive_free(a));
+}

diff --git a/libarchive/test/test_read_format_rar5_bad_tables.rar.uu b/libarchive/test/test_read_format_rar5_bad_tables.rar.uu
new file mode 100644 (file)
index 0000000..eca915f
--- /dev/null
+++ b/libarchive/test/test_read_format_rar5_bad_tables.rar.uu
@@ -0,0 +1,8 @@
+begin 644 test_read_format_rar5_bad_tables.rar
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+`
+end