Re: gawk: invalid read and write

[Aharon Robbins]

These are now applied. Much thanks!

I have added a 'valgrind' target to the top-level Makefile.am to run
valgrind on the test suite, thanks for the inspiration.

Arnold

> Date: Fri, 08 Dec 2006 00:01:59 +0100
> From: Ralf Wildenhues <address@hidden>
> Subject: gawk: invalid read and write
> To: address@hidden
>
> The patch below fixes a couple of invalid reads and writes.
> The errors were all exposed by
>   cd test
>   make check AWK="valgrind --log-file=log ../gawk"
>
> More specifically, the patch fixes the second and fourth of these
> failures below.  The third seems to be due to a bug in the regex
> source (I haven't tested updated versions from gnulib or glibc).
> I don't know whether the first is valid or a false positive of valgrind,
> but it appears both with and without optimization.
>
> 1)
> ==7543== My PID = 7543, parent PID = 7542.  Prog and args are:
> ==7543==    ../gawk
> ==7543==    -f
> ==7543==    fnarray.awk
> ==7543==
> ==7543== Invalid read of size 4
> ==7543==    at 0x40DBE9: yyparse (awkgram.y:797)
> ==7543==    by 0x42860B: main (main.c:565)
> ==7543==  Address 0x501D298 is 0 bytes inside a block of size 2 alloc'd
> ==7543==    at 0x4A19B15: malloc (vg_replace_malloc.c:207)
> ==7543==    by 0x40D1FE: yyparse (awkgram.y:2255)
> ==7543==    by 0x42860B: main (main.c:565)
>
> 2)
> ==9020==    ../gawk
> ==9020==    -f
> ==9020==    fieldwdth.awk
> ==9020==
> ==9020== Invalid write of size 4
> ==9020==    at 0x421783: set_FIELDWIDTHS (field.c:957)
> ==9020==    by 0x43A4BB: r_tree_eval (eval.c:1208)
> ==9020==    by 0x43BB79: interpret (eval.c:877)
> ==9020==    by 0x43BCD5: interpret (eval.c:456)
> ==9020==    by 0x428A8B: main (main.c:603)
> ==9020==  Address 0x501D0D8 is 0 bytes after a block of size 16 alloc'd
> ==9020==    at 0x4A19B15: malloc (vg_replace_malloc.c:207)
> ==9020==    by 0x421804: set_FIELDWIDTHS (field.c:921)
> ==9020==    by 0x43A4BB: r_tree_eval (eval.c:1208)
> ==9020==    by 0x43BB79: interpret (eval.c:877)
> ==9020==    by 0x43BCD5: interpret (eval.c:456)
> ==9020==    by 0x428A8B: main (main.c:603)
>
> 3)
> ==9124==    ../gawk
> ==9124==    -f
> ==9124==    ignrcase.awk
> ==9124==
> ==9124== Conditional jump or move depends on uninitialised value(s)
> ==9124==    at 0x430B88: re_compile_fastmap_iter (regcomp.c:356)
> ==9124==    by 0x430C9A: re_compile_fastmap (regcomp.c:304)
> ==9124==    by 0x435D2A: re_search_stub (regexec.c:419)
> ==9124==    by 0x436017: re_search (regexec.c:314)
> ==9124==    by 0x42B1B5: research (re.c:248)
> ==9124==    by 0x414938: sub_common (builtin.c:2242)
> ==9124==    by 0x43A26A: r_tree_eval (eval.c:991)
> ==9124==    by 0x43BB79: interpret (eval.c:877)
> ==9124==    by 0x43BE7F: interpret (eval.c:477)
> ==9124==    by 0x43BCD5: interpret (eval.c:456)
> ==9124==    by 0x4249D9: do_input (io.c:461)
> ==9124==    by 0x428AB2: main (main.c:607)
>
> 4)
> ==9212==    ../gawk
> ==9212==    --non-decimal-data
> ==9212==    -v
> ==9212==    a=0x1
> ==9212==    -f
> ==9212==    ../../gawk-stable/test/nondec2.awk
> ==9212==
> ==9212== Conditional jump or move depends on uninitialised value(s)
> ==9212==    at 0x4292AD: r_force_number (node.c:114)
> ==9212==    by 0x427AB7: arg_assign (main.c:1075)
> ==9212==    by 0x428635: main (main.c:524)
>
> Cheers,
> Ralf
>
> 2006-12-08  Ralf Wildenhues  <address@hidden>
>
>         * field.c (set_FIELDWIDTHS): Avoid writing one past the end of
>       the array.
>       * node.c (r_force_number): Avoid reading uninitialized variable.
>
> Index: field.c
> ===================================================================
> RCS file: /cvsroot/gawk/gawk-stable/field.c,v
> retrieving revision 1.2
> diff -u -r1.2 field.c
> --- field.c   11 Aug 2006 12:49:40 -0000      1.2
> +++ field.c   6 Dec 2006 19:57:36 -0000
> @@ -922,7 +922,7 @@
>       FIELDWIDTHS[0] = 0;
>       for (i = 1; ; i++) {
>               unsigned long int tmp;
> -             if (i >= fw_alloc) {
> +             if (i + 1 >= fw_alloc) {
>                       fw_alloc *= 2;
>                       erealloc(FIELDWIDTHS, int *, fw_alloc * sizeof(int), 
> "set_FIELDWIDTHS");
>               }
> Index: node.c
> ===================================================================
> RCS file: /cvsroot/gawk/gawk-stable/node.c,v
> retrieving revision 1.2
> diff -u -r1.2 node.c
> --- node.c    11 Aug 2006 12:49:40 -0000      1.2
> +++ node.c    6 Dec 2006 19:57:37 -0000
> @@ -96,6 +96,7 @@
>               if (! do_traditional && isnondecimal(cp, TRUE)) {
>                       n->numbr = nondec2awknum(cp, cpend - cp);
>                       n->flags |= NUMCUR;
> +                     ptr = cpend;
>                       goto finish;
>               }
>       }