libbacktrace: fix UBSAN issues

Fix issues mentioned in the PR.

	PR libbacktrace/103167

libbacktrace/ChangeLog:

	* elf.c (elf_uncompress_lzma_block): Cast to unsigned int.
	(elf_uncompress_lzma): Likewise.
	* xztest.c (test_samples): memcpy only if v > 0.

diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
index 79d56146fc67206d6f7f883a55b27eda7d168e23..8b87b2dd6b9069697eb43f5c1c940f37c68e062f 100644 (file)
--- a/libbacktrace/elf.c
+++ b/libbacktrace/elf.c
@@ -3172,10 +3172,10 @@ elf_uncompress_lzma_block (const unsigned char *compressed,
   /* Block header CRC.  */
   computed_crc = elf_crc32 (0, compressed + block_header_offset,
                            block_header_size - 4);
-  stream_crc = (compressed[off]
-               | (compressed[off + 1] << 8)
-               | (compressed[off + 2] << 16)
-               | (compressed[off + 3] << 24));
+  stream_crc = ((uint32_t)compressed[off]
+               | ((uint32_t)compressed[off + 1] << 8)
+               | ((uint32_t)compressed[off + 2] << 16)
+               | ((uint32_t)compressed[off + 3] << 24));
   if (unlikely (computed_crc != stream_crc))
     {
       elf_uncompress_failed ();
@@ -3785,10 +3785,10 @@ elf_uncompress_lzma (struct backtrace_state *state,
 
   /* Next comes a CRC of the stream flags.  */
   computed_crc = elf_crc32 (0, compressed + 6, 2);
-  stream_crc = (compressed[8]
-               | (compressed[9] << 8)
-               | (compressed[10] << 16)
-               | (compressed[11] << 24));
+  stream_crc = ((uint32_t)compressed[8]
+               | ((uint32_t)compressed[9] << 8)
+               | ((uint32_t)compressed[10] << 16)
+               | ((uint32_t)compressed[11] << 24));
   if (unlikely (computed_crc != stream_crc))
     {
       elf_uncompress_failed ();
@@ -3829,10 +3829,10 @@ elf_uncompress_lzma (struct backtrace_state *state,
 
   /* Before that is a footer CRC.  */
   computed_crc = elf_crc32 (0, compressed + offset, 6);
-  stream_crc = (compressed[offset - 4]
-               | (compressed[offset - 3] << 8)
-               | (compressed[offset - 2] << 16)
-               | (compressed[offset - 1] << 24));
+  stream_crc = ((uint32_t)compressed[offset - 4]
+               | ((uint32_t)compressed[offset - 3] << 8)
+               | ((uint32_t)compressed[offset - 2] << 16)
+               | ((uint32_t)compressed[offset - 1] << 24));
   if (unlikely (computed_crc != stream_crc))
     {
       elf_uncompress_failed ();
@@ -3888,10 +3888,10 @@ elf_uncompress_lzma (struct backtrace_state *state,
   /* Next is a CRC of the index.  */
   computed_crc = elf_crc32 (0, compressed + index_offset,
                            offset - index_offset);
-  stream_crc = (compressed[offset]
-               | (compressed[offset + 1] << 8)
-               | (compressed[offset + 2] << 16)
-               | (compressed[offset + 3] << 24));
+  stream_crc = ((uint32_t)compressed[offset]
+               | ((uint32_t)compressed[offset + 1] << 8)
+               | ((uint32_t)compressed[offset + 2] << 16)
+               | ((uint32_t)compressed[offset + 3] << 24));
   if (unlikely (computed_crc != stream_crc))
     {
       elf_uncompress_failed ();

diff --git a/libbacktrace/xztest.c b/libbacktrace/xztest.c
index b2533cb180457aa73eb533c49c6b8e35dbf7a46a..6c60ff5015917c7df73b98519350f1d6ac651247 100644 (file)
--- a/libbacktrace/xztest.c
+++ b/libbacktrace/xztest.c
@@ -172,7 +172,7 @@ test_samples (struct backtrace_state *state)
                       tests[i].name, uncompressed_len, v);
              ++failures;
            }
-         else if (memcmp (tests[i].uncompressed, uncompressed, v) != 0)
+         else if (v > 0 && memcmp (tests[i].uncompressed, uncompressed, v) != 0)
            {
              size_t j;