Re: [open-cobol-list] bug report: SIGSEGV in GOBACK

[Sergey Kashyrin]

Hi,

Can't provide the patch at the moment, but

Find the function cob_sys_copy_file in fileio.c

Replace following 2 lines
    while ((i = read (fd1, fn1, sizeof(fn1))) > 0) {
        if (write (fd2, fn1, (size_t)i) < 0) {
by
    while ((i = read (fd1, file_open_buff, COB_FILE_BUFF)) > 0) {
        if (write (fd2, file_open_buff, (size_t)i) < 0) {

This bug was there from the beginning - using memory block after "free", 
which on some systems corrupting the heap structure.

Regards,
Sergey


On 11/24/2013 8:48 AM, Matthew Fisher wrote:
> This report refers to the gnu-cobol-2.0 branch, checked out today from:
>
>       svn://svn.code.sf.net/p/open-cobol/code/branches/gnu-cobol-2.0
>
> Under certain conditions, a segmentation fault occurs on line 212 of
> libcob/common.c.
>
> A minimal test program (compiled with `cobc -xg test.cbl`):
>
>          IDENTIFICATION DIVISION.
>          PROGRAM-ID. test.
>
>          DATA DIVISION.
>          WORKING-STORAGE SECTION.
>          01  CALL-STATUS  BINARY-LONG.
>
>          PROCEDURE DIVISION.
>              CALL "C$COPY"
>                  USING "test.cbl" "copy.cbl" "S"
>                  GIVING CALL-STATUS
>              END-CALL
>
>              GOBACK
>              .
>
> The output from running the program:
>
>       test.cbl: 14 Attempt to reference unallocated memory (Signal
>       SIGSEGV)
>       Abnormal termination - File contents may be incorrect
>
> Line 14 is the GOBACK statement. When run in gdb, with a breakpoint
> set in cob_exit_common, it can be seen that the seg fault occurs on
> the free statement in line 212 of libcob/common.c:
>
>       if (cobglobptr->cob_term_buff) {
>           free (cobglobptr->cob_term_buff);
>       }
>
>
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