#2776 SEGV on plot3d_points()

[liuchenyifan]

version: gnuplot 6.1 last modified 2025-03-05
system: ubuntu 22.04

use this command to reproduce: gnutplot poc
message from ASAN:

=================================================================
==1120077==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000050 (pc 0x5596fe9f3434 bp 0x0ab2dfe16cc0 sp 0x7fff71753bc0 T0)
==1120077==The signal is caused by a READ memory access.
==1120077==Hint: address points to the zero page.
#0 0x5596fe9f3434 in plot3d_points /home/ubuntu/asan_program/gnuplot-main/src/graph3d.c:2167
#1 0x5596fea33586 in do_3dplot /home/ubuntu/asan_program/gnuplot-main/src/graph3d.c:1242
#2 0x5596febe9053 in eval_3dplots /home/ubuntu/asan_program/gnuplot-main/src/plot3d.c:3057
#3 0x5596fe91c1dc in splot_command /home/ubuntu/asan_program/gnuplot-main/src/command.c:2749
#4 0x5596fe912981 in command /home/ubuntu/asan_program/gnuplot-main/src/command.c:855
#5 0x5596fe912981 in step_through_line /home/ubuntu/asan_program/gnuplot-main/src/command.c:549
#6 0x5596feb26543 in load_file /home/ubuntu/asan_program/gnuplot-main/src/misc.c:393
#7 0x5596fe8a9404 in main /home/ubuntu/asan_program/gnuplot-main/src/plot.c:669
#8 0x7f74f0a52d8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
#9 0x7f74f0a52e3f in __libc_start_main_impl ../csu/libc-start.c:392
#10 0x5596fe8aacd4 in _start (/home/ubuntu/asan_program/gnuplot-main/src/gnuplot+0xe0cd4)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/ubuntu/asan_program/gnuplot-main/src/graph3d.c:2167 in plot3d_points
==1120077==ABORTING

[Ethan Merritt]

This one is a real bug.
Much simpler reproducer:

set linetype 2 pointtype 'A'
splot  0 with dots linetype 2

[Ethan Merritt]

Fixed for 6.0 and 6.1