Re: [PATCH] libbacktrace: fix UBSAN issues

2021-11-12 Thread Martin Liška 

On 11/11/21 20:21, Ian Lance Taylor wrote:

On Thu, Nov 11, 2021 at 7:39 AM Martin Liška  wrote:


Patch can bootstrap on x86_64-linux-gnu and survives regression tests.

Ready to be installed?
Thanks,
Martin

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.

Co-Authored-By: Andrew Pinski 
---
   libbacktrace/elf.c| 8 
   libbacktrace/xztest.c | 2 +-
   2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
index 79d56146fc6..e69ac41c88b 100644
--- a/libbacktrace/elf.c
+++ b/libbacktrace/elf.c
@@ -3175,7 +3175,7 @@ elf_uncompress_lzma_block (const unsigned char 
*compressed,
 stream_crc = (compressed[off]
 | (compressed[off + 1] << 8)
 | (compressed[off + 2] << 16)
-   | (compressed[off + 3] << 24));
+   | ((unsigned)(compressed[off + 3]) << 24));


Thanks, but this kind of thing looks strange and is therefore likely
to break again in the future.  I suggest instead

   stream_crc = ((uint32_t) compressed[off]
  | ((uint32_t) compressed[off + 1] << 8)
  | ((uint32_t) compressed[off + 2] << 16)
  | ((uint32_t) compressed[off + 3] << 24));

Same for the similar cases elsewhere.


Sure, done and pushed as g:83310a08a2bc52b6e8c3a3e3216b4e723e58c961.

Thanks,
Martin



Ian

Re: [PATCH] libbacktrace: fix UBSAN issues

2021-11-11 Thread Ian Lance Taylor via Gcc-patches 
On Thu, Nov 11, 2021 at 7:39 AM Martin Liška  wrote:
>
> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>
> Ready to be installed?
> Thanks,
> Martin
>
> 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.
>
> Co-Authored-By: Andrew Pinski 
> ---
>   libbacktrace/elf.c| 8 
>   libbacktrace/xztest.c | 2 +-
>   2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
> index 79d56146fc6..e69ac41c88b 100644
> --- a/libbacktrace/elf.c
> +++ b/libbacktrace/elf.c
> @@ -3175,7 +3175,7 @@ elf_uncompress_lzma_block (const unsigned char 
> *compressed,
> stream_crc = (compressed[off]
> | (compressed[off + 1] << 8)
> | (compressed[off + 2] << 16)
> -   | (compressed[off + 3] << 24));
> +   | ((unsigned)(compressed[off + 3]) << 24));

Thanks, but this kind of thing looks strange and is therefore likely
to break again in the future.  I suggest instead

  stream_crc = ((uint32_t) compressed[off]
 | ((uint32_t) compressed[off + 1] << 8)
 | ((uint32_t) compressed[off + 2] << 16)
 | ((uint32_t) compressed[off + 3] << 24));

Same for the similar cases elsewhere.

Ian

[PATCH] libbacktrace: fix UBSAN issues

2021-11-11 Thread Martin Liška 

Patch can bootstrap on x86_64-linux-gnu and survives regression tests.

Ready to be installed?
Thanks,
Martin

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.

Co-Authored-By: Andrew Pinski 
---
 libbacktrace/elf.c| 8 
 libbacktrace/xztest.c | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/libbacktrace/elf.c b/libbacktrace/elf.c
index 79d56146fc6..e69ac41c88b 100644
--- a/libbacktrace/elf.c
+++ b/libbacktrace/elf.c
@@ -3175,7 +3175,7 @@ elf_uncompress_lzma_block (const unsigned char 
*compressed,
   stream_crc = (compressed[off]
| (compressed[off + 1] << 8)
| (compressed[off + 2] << 16)
-   | (compressed[off + 3] << 24));
+   | ((unsigned)(compressed[off + 3]) << 24));
   if (unlikely (computed_crc != stream_crc))
 {
   elf_uncompress_failed ();
@@ -3788,7 +3788,7 @@ elf_uncompress_lzma (struct backtrace_state *state,
   stream_crc = (compressed[8]
| (compressed[9] << 8)
| (compressed[10] << 16)
-   | (compressed[11] << 24));
+   | ((unsigned)(compressed[11]) << 24));
   if (unlikely (computed_crc != stream_crc))
 {
   elf_uncompress_failed ();
@@ -3832,7 +3832,7 @@ elf_uncompress_lzma (struct backtrace_state *state,
   stream_crc = (compressed[offset - 4]
| (compressed[offset - 3] << 8)
| (compressed[offset - 2] << 16)
-   | (compressed[offset - 1] << 24));
+   | ((unsigned)(compressed[offset - 1]) << 24));
   if (unlikely (computed_crc != stream_crc))
 {
   elf_uncompress_failed ();
@@ -3891,7 +3891,7 @@ elf_uncompress_lzma (struct backtrace_state *state,
   stream_crc = (compressed[offset]
| (compressed[offset + 1] << 8)
| (compressed[offset + 2] << 16)
-   | (compressed[offset + 3] << 24));
+   | ((unsigned)(compressed[offset + 3]) << 24));
   if (unlikely (computed_crc != stream_crc))
 {
   elf_uncompress_failed ();
diff --git a/libbacktrace/xztest.c b/libbacktrace/xztest.c
index b2533cb1804..6c60ff50159 100644
--- 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;
 
--

2.33.1