Re: [dpdk-dev] [PATCH v6 1/2] Enable ASan for memory detector on DPDK

[David Marchand <david.marchand@redhat.com>]

Hello,

I see v6 is superseded in pw, I have been cleaning my queue... maybe my fault.


On Thu, Sep 30, 2021 at 7:37 AM <zhihongx.peng@intel.com> wrote:
>
> From: Zhihong Peng <zhihongx.peng@intel.com>
>
> AddressSanitizer (ASan) is a google memory error detect
> standard tool. It could help to detect use-after-free and
> {heap,stack,global}-buffer overflow bugs in C/C++ programs,
> print detailed error information when error happens, large
> improve debug efficiency.
>
> `AddressSanitizer
> <https://github.com/google/sanitizers/wiki/AddressSanitizer>` (ASan)
> is a widely-used debugging tool to detect memory access errors.
> It helps detect issues like use-after-free, various kinds of buffer
> overruns in C/C++ programs, and other similar errors, as well as
> printing out detailed debug information whenever an error is detected.

This patch mixes how to use ASan and instrumenting the DPDK mem allocator.

I would split this patch in two.

The first patch can add the documentation on enabling/using ASan and
describe the known issues on enabling it.
I'd find it better (from a user pov) if we hide all those details
about b_lundef and installation of libasan on Centos.

Something like (only quickly tested):

diff --git a/config/meson.build b/config/meson.build
index 4cdf589e20..7d8b71da79 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -411,6 +411,33 @@ if get_option('b_lto')
     endif
 endif

+if get_option('b_sanitize') == 'address'
+    asan_dep = cc.find_library('asan', required: true)
+    if (not cc.links('int main(int argc, char *argv[]) { return 0; }',
+                     dependencies: asan_dep))
+        error('broken dependency, "libasan"')
+    endif
+    add_project_link_arguments('-lasan', language: 'c')
+    dpdk_extra_ldflags += '-lasan'
+endif
+
 if get_option('default_library') == 'both'
     error( '''
  Unsupported value "both" for "default_library" option.


Bruce, do you see an issue with this approach?


Then a second patch adds the rte_malloc instrumentation, with a check
at configuration time.

     endif
     add_project_link_arguments('-lasan', language: 'c')
     dpdk_extra_ldflags += '-lasan'
+    if arch_subdir == 'x86'
+        asan_check_code = '''
+#ifdef __SANITIZE_ADDRESS__
+#define RTE_MALLOC_ASAN
+#elif defined(__has_feature)
+# if __has_feature(address_sanitizer)
+#define RTE_MALLOC_ASAN
+# endif
+#endif
+
+#ifndef RTE_MALLOC_ASAN
+#error ASan not available.
+#endif
+'''
+        if cc.compiles(asan_check_code)
+            dpdk_conf.set10('RTE_MALLOC_ASAN', true)
+        endif
+    endif
 endif

 if get_option('default_library') == 'both'


Few more comments:


>
> DPDK ASan functionality is currently only supported Linux x86_64.
> Support other platforms, need to define ASAN_SHADOW_OFFSET value
> according to google ASan document.
>
> Here is an example of heap-buffer-overflow bug:
>         ......
>         char *p = rte_zmalloc(NULL, 7, 0);
>         p[7] = 'a';
>         ......
>
> Here is an example of use-after-free bug:
>         ......
>         char *p = rte_zmalloc(NULL, 7, 0);
>         rte_free(p);
>         *p = 'a';
>         ......
>
> If you want to use this feature,
> you need to add below compilation options when compiling code:
> -Dbuildtype=debug -Db_lundef=false -Db_sanitize=address
> "-Dbuildtype=debug": This is a non-essential option. When this option
> is added, if a memory error occurs, ASan can clearly show where the
> code is wrong.
> "-Db_lundef=false": When use clang to compile DPDK, this option must
> be added.
>
> Signed-off-by: Xueqin Lin <xueqin.lin@intel.com>
> Signed-off-by: Zhihong Peng <zhihongx.peng@intel.com>
> ---
>  devtools/words-case.txt         |   1 +
>  doc/guides/prog_guide/ASan.rst  | 108 +++++++++++++++++
>  doc/guides/prog_guide/index.rst |   1 +
>  examples/helloworld/main.c      |   5 +
>  lib/eal/common/malloc_elem.c    |  26 +++-
>  lib/eal/common/malloc_elem.h    | 204 +++++++++++++++++++++++++++++++-
>  lib/eal/common/malloc_heap.c    |  12 ++
>  lib/eal/common/rte_malloc.c     |   9 +-
>  8 files changed, 361 insertions(+), 5 deletions(-)
>  create mode 100644 doc/guides/prog_guide/ASan.rst
>
> diff --git a/devtools/words-case.txt b/devtools/words-case.txt
> index 0bbad48626..3655596d47 100644
> --- a/devtools/words-case.txt
> +++ b/devtools/words-case.txt
> @@ -86,3 +86,4 @@ VXLAN
>  Windows
>  XDP
>  XOR
> +ASan

Alphabetical order please.


> diff --git a/doc/guides/prog_guide/ASan.rst b/doc/guides/prog_guide/ASan.rst

Filenames are lowercase in the doc.


> new file mode 100644
> index 0000000000..7145a3b1a1
> --- /dev/null
> +++ b/doc/guides/prog_guide/ASan.rst
> @@ -0,0 +1,108 @@
> +.. Copyright (c) <2021>, Intel Corporation
> +   All rights reserved.
> +
> +Memory error detect standard tool - AddressSanitizer(ASan)
> +==========================================================
> +
> +AddressSanitizer (ASan) is a google memory error detect
> +standard tool. It could help to detect use-after-free and
> +{heap,stack,global}-buffer overflow bugs in C/C++ programs,
> +print detailed error information when error happens, large
> +improve debug efficiency.
> +
> +By referring to its implementation algorithm
> +(https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm),
> +enabled heap-buffer-overflow and use-after-free functions on DPDK.
> +DPDK ASan function currently only supports on Linux x86_64.
> +
> +AddressSanitizer is a part of LLVM(3.1+)and GCC(4.8+).

missing spaces around ().


> +
> +Example heap-buffer-overflow error
> +----------------------------------
> +
> +Following error was reported when ASan was enabled::
> +
> +    Applied 9 bytes of memory, but accessed the 10th byte of memory,
> +    so heap-buffer-overflow appeared.
> +
> +Below code results in this error::
> +
> +    char *p = rte_zmalloc(NULL, 9, 0);
> +    if (!p) {
> +        printf("rte_zmalloc error.");
> +        return -1;
> +    }
> +    p[9] = 'a';
> +
> +The error log::
> +
> +    ==49433==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f773fafa249 at pc 0x5556b13bdae4 bp 0x7ffeb4965e40 sp 0x7ffeb4965e30 WRITE of size 1 at 0x7f773fafa249 thread T0
> +    #0 0x5556b13bdae3 in asan_heap_buffer_overflow ../app/test/test_asan_heap_buffer_overflow.c:25

Please update this example since the unit test has been removed.


> +    #1 0x5556b043e9d4 in cmd_autotest_parsed ../app/test/commands.c:71
> +    #2 0x5556b1cdd4b0 in cmdline_parse ../lib/cmdline/cmdline_parse.c:290
> +    #3 0x5556b1cd8987 in cmdline_valid_buffer ../lib/cmdline/cmdline.c:26
> +    #4 0x5556b1ce477a in rdline_char_in ../lib/cmdline/cmdline_rdline.c:421
> +    #5 0x5556b1cd923e in cmdline_in ../lib/cmdline/cmdline.c:149
> +    #6 0x5556b1cd9769 in cmdline_interact ../lib/cmdline/cmdline.c:223
> +    #7 0x5556b045f53b in main ../app/test/test.c:234
> +    #8 0x7f7f1eba90b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
> +    #9 0x5556b043e70d in _start (/home/pzh/yyy/x86_64-native-linuxapp-gcc/app/test/dpdk-test+0x7ce70d)
> +
> +    Address 0x7f773fafa249 is a wild pointer.
> +    SUMMARY: AddressSanitizer: heap-buffer-overflow ../app/test/test_asan_heap_buffer_overflow.c:25 in asan_heap_buffer_overflow
> +
> +Example use-after-free error
> +----------------------------
> +
> +Following error was reported when ASan was enabled::
> +
> +    Applied for 9 bytes of memory, and accessed the first byte after
> +    released, so heap-use-after-free appeared.
> +
> +Below code results in this error::
> +
> +    char *p = rte_zmalloc(NULL, 9, 0);
> +    if (!p) {
> +        printf("rte_zmalloc error.");
> +        return -1;
> +    }
> +    rte_free(p);
> +    *p = 'a';
> +
> +The error log::
> +
> +    ==49478==ERROR: AddressSanitizer: heap-use-after-free on address 0x7fe2ffafa240 at pc 0x56409b084bc8 bp 0x7ffef62c57d0 sp 0x7ffef62c57c0 WRITE of size 1 at 0x7fe2ffafa240 thread T0
> +    #0 0x56409b084bc7 in asan_use_after_free ../app/test/test_asan_use_after_free.c:26

Idem.


> +    #1 0x56409a1059d4 in cmd_autotest_parsed ../app/test/commands.c:71
> +    #2 0x56409b9a44b0 in cmdline_parse ../lib/cmdline/cmdline_parse.c:290
> +    #3 0x56409b99f987 in cmdline_valid_buffer ../lib/cmdline/cmdline.c:26
> +    #4 0x56409b9ab77a in rdline_char_in ../lib/cmdline/cmdline_rdline.c:421
> +    #5 0x56409b9a023e in cmdline_in ../lib/cmdline/cmdline.c:149
> +    #6 0x56409b9a0769 in cmdline_interact ../lib/cmdline/cmdline.c:223
> +    #7 0x56409a12653b in main ../app/test/test.c:234
> +    #8 0x7feafafc20b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
> +    #9 0x56409a10570d in _start (/home/pzh/yyy/x86_64-native-linuxapp-gcc/app/test/dpdk-test+0x7ce70d)
> +
> +    Address 0x7fe2ffafa240 is a wild pointer.
> +    SUMMARY: AddressSanitizer: heap-use-after-free ../app/test/test_asan_use_after_free.c:26 in asan_use_after_free


-- 
David Marchand