[Bug] Global-buffer-overflow in `read_` at `src/fe.c:516`

[oneafter]

Dear fe Maintainers,

I would like to report a Global-buffer-overflow issue discovered in fe.

Description

The crash occurs within the read_ function in src/fe.c at line 516, leading to an invalid read access of size 1.

Environment

• OS: Linux x86_64
• Complier: Clang
• Affected Version: master-branch
• Build Configuration: Release mode with ASan enabled.

Reproduce

1. Build fe with Release optimization and ASAN enabled.
2. Run with the crashing file:

./fe repro

ASAN report

==3550135==ERROR: AddressSanitizer: global-buffer-overflow on address 0x5f51d562d067 at pc 0x5f51d560c8fd bp 0x7ffeb5199d90 sp 0x7ffeb5199d88
READ of size 1 at 0x5f51d562d067 thread T0
    #0 0x5f51d560c8fc in read_ /home/cobot001/src/fe/src/fe.c:516:43
    #1 0x5f51d560c165 in read_ /home/cobot001/src/fe/src/fe.c:488:20
    #2 0x5f51d560ba8f in read_ /home/cobot001/src/fe/src/fe.c:488:20
    #3 0x5f51d5611d55 in fe_read /home/cobot001/src/fe/src/fe.c:541:20
    #4 0x5f51d5611d55 in fe_readfp /home/cobot001/src/fe/src/fe.c:554:10
    #5 0x5f51d5611d55 in main /home/cobot001/src/fe/src/fe.c:871:17
    #6 0x7392be82a1c9 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #7 0x7392be82a28a in __libc_start_main csu/../csu/libc-start.c:360:3
    #8 0x5f51d552c474 in _start (/home/cobot001/src/fe/fe_asan+0x2e474) (BuildId: b00c01becada2eac51acf1c9c6d235cca9ef45f5)

0x5f51d562d067 is located 57 bytes before global variable '.str.38' defined in '/home/cobot001/src/fe/src/fe.c:769' (0x5f51d562d0a0) of size 33
  '.str.38' is ascii string 'tried to call non-callable value'
0x5f51d562d067 is located 25 bytes before global variable '.str.36' defined in '/home/cobot001/src/fe/src/fe.c:526' (0x5f51d562d080) of size 16
  '.str.36' is ascii string 'symbol too long'
0x5f51d562d067 is located 0 bytes after global variable '.str.35' defined in '/home/cobot001/src/fe/src/fe.c:516' (0x5f51d562d060) of size 7
  '.str.35' is ascii string 'n
t	'
SUMMARY: AddressSanitizer: global-buffer-overflow /home/cobot001/src/fe/src/fe.c:516:43 in read_
Shadow bytes around the buggy address:
  0x5f51d562cd80: 03 f9 f9 f9 00 00 00 02 f9 f9 f9 f9 03 f9 f9 f9
  0x5f51d562ce00: 00 06 f9 f9 00 00 04 f9 f9 f9 f9 f9 05 f9 f9 f9
  0x5f51d562ce80: 05 f9 f9 f9 07 f9 f9 f9 07 f9 f9 f9 07 f9 f9 f9
  0x5f51d562cf00: 05 f9 f9 f9 06 f9 f9 f9 05 f9 f9 f9 06 f9 f9 f9
  0x5f51d562cf80: 04 f9 f9 f9 00 06 f9 f9 02 f9 f9 f9 00 02 f9 f9
=>0x5f51d562d000: 06 f9 f9 f9 00 00 f9 f9 04 f9 f9 f9[07]f9 f9 f9
  0x5f51d562d080: 00 00 f9 f9 00 00 00 00 01 f9 f9 f9 f9 f9 f9 f9
  0x5f51d562d100: 04 f9 f9 f9 02 f9 f9 f9 03 f9 f9 f9 03 f9 f9 f9
  0x5f51d562d180: 04 f9 f9 f9 06 f9 f9 f9 04 f9 f9 f9 03 f9 f9 f9
  0x5f51d562d200: 03 f9 f9 f9 05 f9 f9 f9 04 f9 f9 f9 04 f9 f9 f9
  0x5f51d562d280: 07 f9 f9 f9 07 f9 f9 f9 05 f9 f9 f9 04 f9 f9 f9
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
==3550135==ABORTING

Please let me know if you need any further information.

Best regards.