Différences

Ci-dessous, les différences entre deux révisions de la page.

--- prog:gcc [2021/04/17 23:18] – Ajout des liens vers les status root
+++ prog:gcc [2024/11/12 12:48] (Version actuelle) – Déplacement des sanitizer vers une page dédiée root
@@ Ligne 2: / Ligne 2: @@
 [[https://gcc.gnu.org/projects/cxx-status.html|C++ status]], [[https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html|libstdc++ status]]
+====Ubuntu====
+  * Installation en parallèle
+Ubuntu ne fournit pas de méthode 100% automatique. Il faut passer manuellement par ''update-alternatives''.
+<code bash>
+sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-11 110 --slave /usr/bin/g++ g++ /usr/bin/g++-11
+</code>
+Utiliser pour switcher entre les versions :
+<code bash>
+sudo update-alternatives --config gcc
+</code>
 =====Diagnostic=====
@@ Ligne 119: / Ligne 135: @@
 En option, on supprime la date pour qu'un diff simple puisse se faire.
-=====Commun avec clang=====
-====Sanitizer====
-Il existe ''-fsanitize=address,thread,undefined'' mais ''address'' et ''thread'' ne sont pas compatible simultanément.
-===address===
-Il détecte des erreurs de type global-buffer-overflow, heap-use-after-free.
-[[https://www.youtube.com/watch?v=qTkYDA0En6U|CppCon 2015: Kostya Serebryany “Beyond Sanitizers, Fuzzing and Hardening your C++ apps for Security and Reliability”]]
-  * global-buffer-overflow
-<file c main.c>
-int global_array[100] = {-1};
-int main(int argc, char **argv) {
-  return global_array[argc+100];
-}
-</file>
-  gcc main.c -g -fsanitize=address -o main && ./main
-  =================================================================
-  ==2500==ERROR: AddressSanitizer: global-buffer-overflow on address 0x000000740cf4 at pc 0x00000050d9bf bp 0x7ffeabb89b70 sp 0x7ffeabb89b68
-  READ of size 4 at 0x000000740cf4 thread T0
-      #0 0x50d9be in main /tmp/main.c:4:10
-      #1 0x7f1208faa461 in __libc_start_main /home/legarrec/info/portage/sys-libs/glibc-2.25-r9/work/glibc-2.25/csu/../csu/libc-start.c:295
-      #2 0x419709 in _start (/tmp/main+0x419709)
-x000000740cf4 is located 4 bytes to the right of global variable 'global_array' defined in 'main.c:1:5' (0x740b60) of size 400
-  SUMMARY: AddressSanitizer: global-buffer-overflow /tmp/main.c:4:10 in main
-  Shadow bytes around the buggy address:
-x0000800e0140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0000800e0150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0000800e0160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0000800e0170: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0000800e0180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-  =>0x0000800e0190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[f9]f9
-x0000800e01a0: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 00 00 00 00
-x0000800e01b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0000800e01c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0000800e01d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0000800e01e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-  Shadow byte legend (one shadow byte represents 8 application bytes):
-    Addressable:           00
-    Partially addressable: 01 02 03 04 05 06 07
-    Heap left redzone:       fa
-    Freed heap region:       fd
-    Stack left redzone:      f1
-    Stack mid redzone:       f2
-    Stack right redzone:     f3
-    Stack after return:      f5
-    Stack use after scope:   f8
-    Global redzone:          f9
-    Global init order:       f6
-    Poisoned by user:        f7
-    Container overflow:      fc
-    Array cookie:            ac
-    Intra object redzone:    bb
-    ASan internal:           fe
-    Left alloca redzone:     ca
-    Right alloca redzone:    cb
-  ==2500==ABORTING
-[[prog:valgrind|valgrind]] ne détecte pas l'erreur.
-  * heap-use-after-free
-<file c main2.cc>
-int main(int argc, char **argv) {
-  int *array = new int[100];
-  delete [] array;
-  return array[argc];
-}
-</file>
-  g++ main2.c -g -fsanitize=address -o main2 && ./main2
-  =================================================================
-  ==2765==ERROR: AddressSanitizer: heap-use-after-free on address 0x614000000044 at pc 0x000000512445 bp 0x7ffd51684f60 sp 0x7ffd51684f58
-  READ of size 4 at 0x614000000044 thread T0
-      #0 0x512444 in main /tmp/main2.c:4:10
-      #1 0x7fd8d0086461 in __libc_start_main /home/legarrec/info/portage/sys-libs/glibc-2.25-r9/work/glibc-2.25/csu/../csu/libc-start.c:295
-      #2 0x419d29 in _start (/tmp/main2+0x419d29)
-x614000000044 is located 4 bytes inside of 400-byte region [0x614000000040,0x6140000001d0)
-  freed by thread T0 here:
-      #0 0x50ef30 in operator delete[](void*) /home/legarrec/info/portage/sys-libs/compiler-rt-sanitizers-5.0.0/work/compiler-rt-5.0.0.src/lib/asan/asan_new_delete.cc:141
-      #1 0x5123f6 in main /tmp/main2.c:3:3
-      #2 0x7fd8d0086461 in __libc_start_main /home/legarrec/info/portage/sys-libs/glibc-2.25-r9/work/glibc-2.25/csu/../csu/libc-start.c:295
-      #3 0x419d29 in _start (/tmp/main2+0x419d29)
-  previously allocated by thread T0 here:
-      #0 0x50e1c8 in operator new[](unsigned long) /home/legarrec/info/portage/sys-libs/compiler-rt-  sanitizers-5.0.0/work/compiler-rt-5.0.0.src/lib/asan/asan_new_delete.cc:95
-      #1 0x5123d4 in main /tmp/main2.c:2:16
-      #2 0x7fd8d0086461 in __libc_start_main /home/legarrec/info/portage/sys-libs/glibc-2.25-r9/work/glibc-2.25/csu/../csu/libc-start.c:295
-      #3 0x419d29 in _start (/tmp/main2+0x419d29)
-  SUMMARY: AddressSanitizer: heap-use-after-free /tmp/main2.c:4:10 in main
-  Shadow bytes around the buggy address:
-x0c287fff7fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0c287fff7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0c287fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0c287fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0c287fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-  =>0x0c287fff8000: fa fa fa fa fa fa fa fa[fd]fd fd fd fd fd fd fd
-x0c287fff8010: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
-x0c287fff8020: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
-x0c287fff8030: fd fd fd fd fd fd fd fd fd fd fa fa fa fa fa fa
-x0c287fff8040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
-x0c287fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
-[[prog:valgrind|valgrind]] détecte l'erreur.
-  ==2787== Command: ./main2
-  ==2787==
-  ==2787== Invalid read of size 4
-  ==2787==    at 0x4005AF: main (main2.c:4)
-  ==2787==  Address 0x5b25c84 is 4 bytes inside a block of size 400 free'd
-  ==2787==    at 0x4C2CAA5: operator delete[](void*) (vg_replace_malloc.c:621)
-  ==2787==    by 0x4005A6: main (main2.c:3)
-  ==2787==  Block was alloc'd at
-  ==2787==    at 0x4C2BAC8: operator new[](unsigned long) (vg_replace_malloc.c:423)
-  ==2787==    by 0x400584: main (main2.c:2)
-  * stack-use-after-return
-<file c main3.c>
-int *g;
-void LeakLocal() {
-  int local;
-  g = &local;
-}
-int main(){
-  LeakLocal();
-  return *g;
-}
-</file>
-  gcc main3.c -g -o main3 -fsanitize=address
-  ASAN_OPTIONS=detect_stack_use_after_return=1 ./main3
-L'utilisation de ''ASAN_OPTIONS=detect_stack_use_after_return=1'' est nécessaire car cette option peut créer des faux positifs.
-  =================================================================
-  ==2907==ERROR: AddressSanitizer: stack-use-after-return on address 0x7f57b2a00020 at pc 0x00000050db25 bp 0x7ffe8dfc7330 sp 0x7ffe8dfc7328
-  READ of size 4 at 0x7f57b2a00020 thread T0
-      #0 0x50db24 in main /tmp/main3.c:10:10
-      #1 0x7f57b604d461 in __libc_start_main /home/legarrec/info/portage/sys-libs/glibc-2.25-r9/work/glibc-2.25/csu/../csu/libc-start.c:295
-      #2 0x419709 in _start (/tmp/main3+0x419709)
-  Address 0x7f57b2a00020 is located in stack of thread T0 at offset 32 in frame
-      #0 0x50d95f in LeakLocal /tmp/main3.c:3
-    This frame has 1 object(s):
-      [32, 36) 'local' (line 4) <== Memory access at offset 32 is inside this variable
-  HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
-        (longjmp and C++ exceptions *are* supported)
-  SUMMARY: AddressSanitizer: stack-use-after-return /tmp/main3.c:10:10 in main
-  Shadow bytes around the buggy address:
-x0feb76537fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0feb76537fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0feb76537fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0feb76537fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0feb76537ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-  =>0x0feb76538000: f5 f5 f5 f5[f5]f5 f5 f5 00 00 00 00 00 00 00 00
-x0feb76538010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0feb76538020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0feb76538030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0feb76538040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-x0feb76538050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-[[prog:valgrind|valgrind]] détecte l'erreur.
-  valgrind --track-origins=yes ./main3
-  ==2961== Syscall param exit_group(status) contains uninitialised byte(s)
-  ==2961==    at 0x4F002B8: _Exit (_exit.c:31)
-  ==2961==    by 0x4E70423: __run_exit_handlers (exit.c:98)
-  ==2961==    by 0x4E704DC: exit (exit.c:105)
-  ==2961==    by 0x4E58468: (below main) (libc-start.c:329)
-  ==2961==  Uninitialised value was created by a stack allocation
-  ==2961==    at 0x4004A4: main (main3.c:10)
-===thread===
-<file cpp main4.cc>
-#include <thread>
-int main() {
-  int x;
-  std::thread t([&]{x=42;});
-  x = 43;
-  t.join();
-  return 0;
-}
-</file>
-  g++ -std=c++11 main4.c -g -o main4 -fsanitize=thread
-<WRAP center round important 60%>
-Le plantage reste aléatoire et il est nécessaire de lancer l'application plusieurs fois.
-</WRAP>
-  ==================
-  WARNING: ThreadSanitizer: data race (pid=3226)
-    Write of size 4 at 0x7ffd04d5b144 by thread T1:
-      #0 operator() /tmp/main4.c:5 (main4+0x000000400d0b)
-      #1 __invoke_impl<void, main()::<lambda()> > /usr/lib/gcc/x86_64-pc-linux-gnu/7.2.0/include/g++-v7/bits/invoke.h:60 (main4+0x000000401171)
-      #2 __invoke<main()::<lambda()> > /usr/lib/gcc/x86_64-pc-linux-gnu/7.2.0/include/g++-v7/bits/invoke.h:95 (main4+0x000000400e30)
-      #3 _M_invoke<0> /usr/lib/gcc/x86_64-pc-linux-gnu/7.2.0/include/g++-v7/thread:234 (main4+0x0000004014b5)
-      #4 operator() /usr/lib/gcc/x86_64-pc-linux-gnu/7.2.0/include/g++-v7/thread:243 (main4+0x000000401448)
-      #5 _M_run /usr/lib/gcc/x86_64-pc-linux-gnu/7.2.0/include/g++-v7/thread:186 (main4+0x0000004013ee)
-      #6 <null> <null> (libstdc++.so.6+0x0000000e251e)
-    Previous write of size 4 at 0x7ffd04d5b144 by main thread:
-      #0 main /tmp/main4.c:6 (main4+0x000000400d75)
-    Location is stack of main thread.
-    Thread T1 (tid=3228, running) created by main thread at:
-      #0 pthread_create <null> (libtsan.so.0+0x00000002917a)
-      #1 std::thread::_M_start_thread(std::unique_ptr<std::thread::_State, std::default_delete<std::thread::_State> >, void (*)()) <null> (libstdc++.so.6+0x0000000e288c)
-      #2 main /tmp/main4.c:5 (main4+0x000000400d69)
-  SUMMARY: ThreadSanitizer: data race /tmp/main4.c:5 in operator()
-  ==================
-  ThreadSanitizer: reported 1 warnings
-[[prog:valgrind|valgrind]] ne détecte pas l'erreur.
-===undefined===
-<file c main5.c>
-int main(int argc, char **argv) {
-  int t = argc << 16;
-  return t*t;
-}
-</file>
-  gcc -fsanitize=undefined main5.c -g -o main5
-  main6.c:3:11: runtime error: signed integer overflow: 65536 * 65536 cannot be represented in type 'int'
-[[prog:valgrind|valgrind]] ne détecte pas l'erreur.