Example: `provenance_via_io_percentp_global.c`

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
int x=1;
int main() {
  int *p = &x;
  FILE *f = fopen(
    "provenance_via_io_percentp_global.tmp","w+b");
  printf("Addresses: p=%p\n",(void*)p);
  // print pointer address to a file
  fprintf(f,"%p\n",(void*)p);
  rewind(f);
  void *rv;
  int n = fscanf(f,"%p\n",&rv);
  int *r = (int *)rv;
  if (n != 1) exit(EXIT_FAILURE);
  printf("Addresses: r=%p\n",(void*)r);
  // are r and p now equivalent?  
  *r=12; // is this free of undefined behaviour?                                                           
  _Bool b1 = (r==p); // do they compare equal?                      
  _Bool b2 = (0==memcmp(&r,&p,sizeof(r)));//same reps?
  printf("x=%i *r=%i b1=%s b2=%s\n",x,*r,
         b1?"true":"false",b2?"true":"false");
}

[link to test in Cerberus and Compiler Explorer]

Experimental data (what does this mean?)


gcc-8.1-O0   Addresses: p=0x600cf0
Addresses: r=0x600cf0
x=12 *r=12 b1=true b2=true

gcc-8.1-O2   Addresses: p=0x600c38
Addresses: r=0x600c38
x=12 *r=12 b1=true b2=true

gcc-8.1-O3   Addresses: p=0x600c38
Addresses: r=0x600c38
x=12 *r=12 b1=true b2=true

gcc-8.1-O2-no-strict-aliasing   Addresses: p=0x600c38
Addresses: r=0x600c38
x=12 *r=12 b1=true b2=true

gcc-8.1-O3-no-strict-aliasing   Addresses: p=0x600c38
Addresses: r=0x600c38
x=12 *r=12 b1=true b2=true

clang-6.0-O0   Addresses: p=0x601068
Addresses: r=0x601068
x=12 *r=12 b1=true b2=true

clang-6.0-O2   Addresses: p=0x601060
Addresses: r=0x601060
x=12 *r=12 b1=true b2=true

clang-6.0-O3   Addresses: p=0x601060
Addresses: r=0x601060
x=12 *r=12 b1=true b2=true

clang-6.0-O2-no-strict-aliasing   Addresses: p=0x601060
Addresses: r=0x601060
x=12 *r=12 b1=true b2=true

clang-6.0-O3-no-strict-aliasing   Addresses: p=0x601060
Addresses: r=0x601060
x=12 *r=12 b1=true b2=true

clang-6.0-UBSAN   Addresses: p=0x632b80
Addresses: r=0x632b80
x=12 *r=12 b1=true b2=true

clang-6.0-ASAN   Addresses: p=0x716b80
Addresses: r=0x716b80
x=12 *r=12 b1=true b2=true

clang-6.0-MSAN   Addresses: p=0x6b7b00
Addresses: r=0x6b7b00
x=12 *r=12 b1=true b2=true

icc-19-O0   Addresses: p=0x600e70
Addresses: r=0x600e70
x=12 *r=12 b1=true b2=true

icc-19-O2   Addresses: p=0x6046e0
Addresses: r=0x6046e0
x=12 *r=12 b1=true b2=true

icc-19-O3   Addresses: p=0x6046e0
Addresses: r=0x6046e0
x=12 *r=12 b1=true b2=true

icc-19-O2-no-strict-aliasing   Addresses: p=0x6046e0
Addresses: r=0x6046e0
x=12 *r=12 b1=true b2=true

icc-19-O3-no-strict-aliasing   Addresses: p=0x6046e0
Addresses: r=0x6046e0
x=12 *r=12 b1=true b2=true

cerberus-concrete   exit codes: compile 0 / execute 1
provenance_via_io_percentp_global.c:17:20: error: [desug] use of undeclared identifier '__cerbvar_EXIT_FAILURE'. (§6.5.1#2)
  if (n != 1) exit(EXIT_FAILURE);
                   ^

cerberus-symbolic   exit codes: compile 0 / execute 1
provenance_via_io_percentp_global.c:17:20: error: [desug] use of undeclared identifier '__cerbvar_EXIT_FAILURE'. (§6.5.1#2)
  if (n != 1) exit(EXIT_FAILURE);
                   ^

gcc-4.9-shadowprov   exit codes: compile 0 / execute 134

CHERI:MIPS-O0   Addresses: p=0x30020
Addresses: r=0x30020
x=12 *r=12 b1=true b2=true

CHERI:MIPS-O2   Addresses: p=0x30020
Addresses: r=0x30020
x=12 *r=12 b1=true b2=true

CHERI:MIPS-O2-no-strict-aliasing   Addresses: p=0x30020
Addresses: r=0x30020
x=12 *r=12 b1=true b2=true

CHERI:CHERI-O0-uintcap-addr-exact-equals   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-addr-exact-equals   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr-exact-equals   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O0-uintcap-offset-exact-equals   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-offset-exact-equals   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-offset-exact-equals   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O0-uintcap-addr   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-addr   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O0-uintcap-offset   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-offset   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-offset   exit codes: compile 0 / execute -1
Terminated with signal 34: In-address space security exception
RV-Match   exit codes: compile 0 / execute 139
Addresses: p=(nil)
Addresses: r=(nil)
Dereferencing a null pointer:
      > in main at provenance_via_io_percentp_global.c:20:3

    Undefined behavior (UB-CER3):
        see C11 section 6.5.3.2:4 http://rvdoc.org/C11/6.5.3.2
        see C11 section J.2:1 item 43 http://rvdoc.org/C11/J.2
        see CERT-C section EXP34-C http://rvdoc.org/CERT-C/EXP34-C
        see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1

Execution failed (configuration dumped)

ch2o   provenance_via_io_percentp_global.c:4:10: fatal error: inttypes.h: No such file or directory
 #include <inttypes.h>
          ^~~~~~~~~~~~
compilation terminated.

compcert-3.2   Addresses: p=0x601068
Addresses: r=0x601068
x=12 *r=12 b1=true b2=true

compcert-3.2-O   Addresses: p=0x601068
Addresses: r=0x601068
x=12 *r=12 b1=true b2=true

compcert-3.2-interp   Time 0: calling main()
--[step_internal_function]-->
Time 1: in function main, statement
  p = &x;
  f = fopen(__stringlit_2, __stringlit_1);
  printf(__stringlit_3, (void *) p);
  fprintf(f, __stringlit_4, (void *) p);
  rewind(f);
  n = fscanf(f, __stringlit_4, &rv);
  r = (int *) rv;
  if (n != 1) {
    exit(1);
  }
  printf(__stringlit_5, (void *) r);
  *r = 12;
  b1 = r == p;
  b2 = 0 == memcmp(&r, &p, sizeof(int *));
  printf(__stringlit_8, x, *r, 
         b1 ? __stringlit_7 : __stringlit_6,
         b2 ? __stringlit_7 : __stringlit_6);
  return 0;
--[step_seq]-->
Time 2: in function main, statement
  p = &x;
  f = fopen(__stringlit_2, __stringlit_1);
  printf(__stringlit_3, (void *) p);
  fprintf(f, __stringlit_4, (void *) p);
  rewind(f);
  n = fscanf(f, __stringlit_4, &rv);
  r = (int *) rv;
  if (n != 1) {
    exit(1);
  }
  printf(__stringlit_5, (void *) r);
  *r = 12;
  b1 = r == p;
  b2 = 0 == memcmp(&r, &p, sizeof(int *));
  printf(__stringlit_8, x, *r, 
         b1 ? __stringlit_7 : __stringlit_6,
         b2 ? __stringlit_7 : __stringlit_6);
--[step_seq]-->
Time 3: in function main, statement p = &x;
--[step_do_1]-->
Time 4: in function main, expression p = &x
--[red_var_local]-->
Time 5: in function main, expression <loc p> = &x
--[red_var_global]-->
Time 6: in function main, expression <loc p> = &<loc x>
--[red_addrof]-->
Time 7: in function main, expression <loc p> = <ptr x>
--[red_assign]-->
Time 8: in function main, expression <ptr x>
--[step_do_2]-->
Time 9: in function main, statement /*skip*/;
--[step_skip_seq]-->
Time 10: in function main, statement
  f = fopen(__stringlit_2, __stringlit_1);
  printf(__stringlit_3, (void *) p);
  fprintf(f, __stringlit_4, (void *) p);
  rewind(f);
  n = fscanf(f, __stringlit_4, &rv);
  r = (int *) rv;
  if (n != 1) {
    exit(1);
  }
  printf(__stringlit_5, (void *) r);
  *r = 12;
  b1 = r == p;
  b2 = 0 == memcmp(&r, &p, sizeof(int *));
  printf(__stringlit_8, x, *r, 
         b1 ? __stringlit_7 : __stringlit_6,
         b2 ? __stringlit_7 : __stringlit_6);
--[step_seq]-->
Time 11: in function main, statement f = fopen(__stringlit_2, __stringlit_1);
--[step_do_1]-->
Time 12: in function main, expression f = fopen(__stringlit_2, __stringlit_1)
--[red_var_local]-->
Time 13: in function main, expression
  <loc f> = fopen(__stringlit_2, __stringlit_1)
--[red_var_global]-->
Time 14: in function main, expression
  <loc f> = <loc fopen>(__stringlit_2, __stringlit_1)
--[red_rvalof]-->
Time 15: in function main, expression
  <loc f> = <ptr fopen>(__stringlit_2, __stringlit_1)
--[red_var_global]-->
Time 16: in function main, expression
  <loc f> = <ptr fopen>(<loc __stringlit_2>, __stringlit_1)
--[red_rvalof]-->
Time 17: in function main, expression
  <loc f> = <ptr fopen>(<ptr __stringlit_2>, __stringlit_1)
--[red_var_global]-->
Time 18: in function main, expression
  <loc f> = <ptr fopen>(<ptr __stringlit_2>, <loc __stringlit_1>)
--[red_rvalof]-->
Time 19: in function main, expression
  <loc f> = <ptr fopen>(<ptr __stringlit_2>, <ptr __stringlit_1>)
--[red_call]-->
Time 20: calling fopen(<ptr __stringlit_2>, <ptr __stringlit_1>)
Stuck state: calling fopen(<ptr __stringlit_2>, <ptr __stringlit_1>)
ERROR: Undefined behavior
In file included from provenance_via_io_percentp_global.c:1:
In file included from /usr/include/stdio.h:64:
In file included from /usr/include/_stdio.h:68:
/usr/include/sys/cdefs.h:81:2: warning: "Unsupported compiler detected" [-W#warnings]
#warning "Unsupported compiler detected"
 ^
1 warning generated.

gcc-8.1-O0		Addresses: p=0x600cf0 Addresses: r=0x600cf0 x=12 *r=12 b1=true b2=true
gcc-8.1-O2		Addresses: p=0x600c38 Addresses: r=0x600c38 x=12 *r=12 b1=true b2=true
gcc-8.1-O3		Addresses: p=0x600c38 Addresses: r=0x600c38 x=12 *r=12 b1=true b2=true
gcc-8.1-O2-no-strict-aliasing		Addresses: p=0x600c38 Addresses: r=0x600c38 x=12 *r=12 b1=true b2=true
gcc-8.1-O3-no-strict-aliasing		Addresses: p=0x600c38 Addresses: r=0x600c38 x=12 *r=12 b1=true b2=true
clang-6.0-O0		Addresses: p=0x601068 Addresses: r=0x601068 x=12 *r=12 b1=true b2=true
clang-6.0-O2		Addresses: p=0x601060 Addresses: r=0x601060 x=12 *r=12 b1=true b2=true
clang-6.0-O3		Addresses: p=0x601060 Addresses: r=0x601060 x=12 *r=12 b1=true b2=true
clang-6.0-O2-no-strict-aliasing		Addresses: p=0x601060 Addresses: r=0x601060 x=12 *r=12 b1=true b2=true
clang-6.0-O3-no-strict-aliasing		Addresses: p=0x601060 Addresses: r=0x601060 x=12 *r=12 b1=true b2=true
clang-6.0-UBSAN		Addresses: p=0x632b80 Addresses: r=0x632b80 x=12 *r=12 b1=true b2=true
clang-6.0-ASAN		Addresses: p=0x716b80 Addresses: r=0x716b80 x=12 *r=12 b1=true b2=true
clang-6.0-MSAN		Addresses: p=0x6b7b00 Addresses: r=0x6b7b00 x=12 *r=12 b1=true b2=true
icc-19-O0		Addresses: p=0x600e70 Addresses: r=0x600e70 x=12 *r=12 b1=true b2=true
icc-19-O2		Addresses: p=0x6046e0 Addresses: r=0x6046e0 x=12 *r=12 b1=true b2=true
icc-19-O3		Addresses: p=0x6046e0 Addresses: r=0x6046e0 x=12 *r=12 b1=true b2=true
icc-19-O2-no-strict-aliasing		Addresses: p=0x6046e0 Addresses: r=0x6046e0 x=12 *r=12 b1=true b2=true
icc-19-O3-no-strict-aliasing		Addresses: p=0x6046e0 Addresses: r=0x6046e0 x=12 *r=12 b1=true b2=true
cerberus-concrete		exit codes: compile 0 / execute 1 provenance_via_io_percentp_global.c:17:20: error: [desug] use of undeclared identifier '__cerbvar_EXIT_FAILURE'. (§6.5.1#2) if (n != 1) exit(EXIT_FAILURE); ^
cerberus-symbolic		exit codes: compile 0 / execute 1 provenance_via_io_percentp_global.c:17:20: error: [desug] use of undeclared identifier '__cerbvar_EXIT_FAILURE'. (§6.5.1#2) if (n != 1) exit(EXIT_FAILURE); ^
gcc-4.9-shadowprov		exit codes: compile 0 / execute 134
CHERI:MIPS-O0		Addresses: p=0x30020 Addresses: r=0x30020 x=12 *r=12 b1=true b2=true
CHERI:MIPS-O2		Addresses: p=0x30020 Addresses: r=0x30020 x=12 *r=12 b1=true b2=true
CHERI:MIPS-O2-no-strict-aliasing		Addresses: p=0x30020 Addresses: r=0x30020 x=12 *r=12 b1=true b2=true
CHERI:CHERI-O0-uintcap-addr-exact-equals		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-addr-exact-equals		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr-exact-equals		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O0-uintcap-offset-exact-equals		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-offset-exact-equals		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-offset-exact-equals		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O0-uintcap-addr		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-addr		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-addr		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O0-uintcap-offset		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-uintcap-offset		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
CHERI:CHERI-O2-no-strict-aliasing-uintcap-offset		exit codes: compile 0 / execute -1 Terminated with signal 34: In-address space security exception
RV-Match		exit codes: compile 0 / execute 139 Addresses: p=(nil) Addresses: r=(nil) Dereferencing a null pointer: > in main at provenance_via_io_percentp_global.c:20:3 Undefined behavior (UB-CER3): see C11 section 6.5.3.2:4 http://rvdoc.org/C11/6.5.3.2 see C11 section J.2:1 item 43 http://rvdoc.org/C11/J.2 see CERT-C section EXP34-C http://rvdoc.org/CERT-C/EXP34-C see MISRA-C section 8.1:3 http://rvdoc.org/MISRA-C/8.1 Execution failed (configuration dumped)
ch2o		provenance_via_io_percentp_global.c:4:10: fatal error: inttypes.h: No such file or directory #include <inttypes.h> ^~~~~~~~~~~~ compilation terminated.
compcert-3.2		Addresses: p=0x601068 Addresses: r=0x601068 x=12 *r=12 b1=true b2=true
compcert-3.2-O		Addresses: p=0x601068 Addresses: r=0x601068 x=12 *r=12 b1=true b2=true
compcert-3.2-interp		Time 0: calling main() --[step_internal_function]--> Time 1: in function main, statement p = &x; f = fopen(__stringlit_2, __stringlit_1); printf(__stringlit_3, (void ) p); fprintf(f, __stringlit_4, (void ) p); rewind(f); n = fscanf(f, __stringlit_4, &rv); r = (int ) rv; if (n != 1) { exit(1); } printf(__stringlit_5, (void ) r); r = 12; b1 = r == p; b2 = 0 == memcmp(&r, &p, sizeof(int )); printf(__stringlit_8, x, r, b1 ? __stringlit_7 : __stringlit_6, b2 ? __stringlit_7 : __stringlit_6); return 0; --[step_seq]--> Time 2: in function main, statement p = &x; f = fopen(__stringlit_2, __stringlit_1); printf(__stringlit_3, (void ) p); fprintf(f, __stringlit_4, (void ) p); rewind(f); n = fscanf(f, __stringlit_4, &rv); r = (int ) rv; if (n != 1) { exit(1); } printf(__stringlit_5, (void ) r); r = 12; b1 = r == p; b2 = 0 == memcmp(&r, &p, sizeof(int )); printf(__stringlit_8, x, r, b1 ? __stringlit_7 : __stringlit_6, b2 ? __stringlit_7 : __stringlit_6); --[step_seq]--> Time 3: in function main, statement p = &x; --[step_do_1]--> Time 4: in function main, expression p = &x --[red_var_local]--> Time 5: in function main, expression <loc p> = &x --[red_var_global]--> Time 6: in function main, expression <loc p> = &<loc x> --[red_addrof]--> Time 7: in function main, expression <loc p> = <ptr x> --[red_assign]--> Time 8: in function main, expression <ptr x> --[step_do_2]--> Time 9: in function main, statement /skip/; --[step_skip_seq]--> Time 10: in function main, statement f = fopen(__stringlit_2, __stringlit_1); printf(__stringlit_3, (void ) p); fprintf(f, __stringlit_4, (void ) p); rewind(f); n = fscanf(f, __stringlit_4, &rv); r = (int ) rv; if (n != 1) { exit(1); } printf(__stringlit_5, (void ) r); r = 12; b1 = r == p; b2 = 0 == memcmp(&r, &p, sizeof(int )); printf(__stringlit_8, x, *r, b1 ? __stringlit_7 : __stringlit_6, b2 ? __stringlit_7 : __stringlit_6); --[step_seq]--> Time 11: in function main, statement f = fopen(__stringlit_2, __stringlit_1); --[step_do_1]--> Time 12: in function main, expression f = fopen(__stringlit_2, __stringlit_1) --[red_var_local]--> Time 13: in function main, expression <loc f> = fopen(__stringlit_2, __stringlit_1) --[red_var_global]--> Time 14: in function main, expression <loc f> = <loc fopen>(__stringlit_2, __stringlit_1) --[red_rvalof]--> Time 15: in function main, expression <loc f> = <ptr fopen>(__stringlit_2, __stringlit_1) --[red_var_global]--> Time 16: in function main, expression <loc f> = <ptr fopen>(<loc __stringlit_2>, __stringlit_1) --[red_rvalof]--> Time 17: in function main, expression <loc f> = <ptr fopen>(<ptr __stringlit_2>, __stringlit_1) --[red_var_global]--> Time 18: in function main, expression <loc f> = <ptr fopen>(<ptr __stringlit_2>, <loc __stringlit_1>) --[red_rvalof]--> Time 19: in function main, expression <loc f> = <ptr fopen>(<ptr __stringlit_2>, <ptr __stringlit_1>) --[red_call]--> Time 20: calling fopen(<ptr __stringlit_2>, <ptr __stringlit_1>) Stuck state: calling fopen(<ptr __stringlit_2>, <ptr __stringlit_1>) ERROR: Undefined behavior In file included from provenance_via_io_percentp_global.c:1: In file included from /usr/include/stdio.h:64: In file included from /usr/include/_stdio.h:68: /usr/include/sys/cdefs.h:81:2: warning: "Unsupported compiler detected" [-W#warnings] #warning "Unsupported compiler detected" ^ 1 warning generated.

Example: provenance_via_io_percentp_global.c

Example: `provenance_via_io_percentp_global.c`