(r)index("") do memory exhausted

[vodzous]

When testing my project 'yacc and jq in bash (ftp://ftp.simtreas.ru/pub/my/yacc_bash_jq.tgz)' I found a error in the jq version 1.6:
index("") and rindex("") do memory exhausted.

[pkoppstein]

Running jq -n '"abc" | index("")' yields null using jq 1.5 or 1.6 (Mac OSX), so it is difficult to know what the problem is, given that there is no JSON or .jq file in the Yacc_bash_jq tarball.

(jq 1.4 did have a problem with index("").)

For the curious:

$ tar ztvf yacc_bash_jq.tgz
drwxr-xr-x  0 dzo    users       0 Jun  9 04:11 yacc_bash_jq/
-rw-r--r--  0 dzo    users     232 Jun  2 04:06 yacc_bash_jq/Makefile
-rw-r--r--  0 dzo    users   33697 Jun  9 03:48 yacc_bash_jq/jq.yb
-rw-r--r--  0 dzo    users   57757 Jun  9 04:11 yacc_bash_jq/yacc_bash.c

[vodzous]

yields null using jq 1.5 or 1.6 jq -n '"abc" | index("")'
I get jq from download https://stedolan.github.io/jq/. All files have the date: Nov 2 2018
$ jq --version
jq-1.6
$ jq -n '"abc" | index("")'
make memory bomb

I think, index("") should eq 'lenght', not null :)

For the curious:
Excuse me, i do not understand.

[pkoppstein]

@vodzous - Which OS?

[vodzous]

Which OS?

Linux x86_64 3.10.17 SMP

[vodzous]

I debugged jq and found infinite loop:
src/jv.c: jv_string_indexes():
while ((p = _jq_memmem(p, (jstr + jlen) - p, idxstr, idxlen)) != NULL) {
fprintf(stderr, "jv_string_indexes: idxlen=%d\n", idxlen);

#2 0x0000000000412ead in memory_exhausted () at src/jv_alloc.c:41
#3 0x0000000000412eda in jv_mem_alloc (sz=4903796368) at src/jv_alloc.c:124
#4 0x000000000040dc91 in jvp_array_alloc (size=306487272) at src/jv.c:186
#5 0x000000000040e124 in jvp_array_write (a=0x7fffffffd7f0, i=204324847) at src/jv.c:246
#6 0x000000000040e8c0 in jv_array_set (j=..., idx=204324847, val=...) at src/jv.c:356
#7 0x000000000040e96b in jv_array_append (j=..., val=...) at src/jv.c:364
#8 0x000000000040fbaf in jv_string_indexes (j=..., k=...) at src/jv.c:663
#9 0x000000000042d62a in f_string_indexes (jq=0x6572e0, a=..., b=...) at src/builtin.c:1126
#10 0x000000000040966f in jq_next (jq=0x6572e0) at src/execute.c:853
#11 0x000000000040374d in process (jq=0x6572e0, value=..., flags=0, dumpopts=645) at src/main.c:168
#12 0x0000000000405b77 in main (argc=3, argv=0x7fffffffe168) at src/main.c:631

[vodzous]

Ah, this corrected in Feb 10 jv.c revision, not in 1.6 version.