On Okt 04 2021, Chet Ramey wrote: > You'd think. This is the kind of overflow that will produce that error > message from the bash malloc:
Only after the fact. valgrind finds it before it is happening, and even if the overflow hits a padding between memory blocks. $ valgrind ./a.out ==31974== Memcheck, a memory error detector ==31974== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. ==31974== Using Valgrind-3.16.1 and LibVEX; rerun with -h for copyright info ==31974== Command: ./a.out ==31974== ==31974== Invalid write of size 1 ==31974== at 0x4006CB: main (in /home/andreas/a.out) ==31974== Address 0x5213068 is 0 bytes after a block of size 40 alloc'd ==31974== at 0x4C312EF: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==31974== by 0x40068F: main (in /home/andreas/a.out) ==31974== ==31974== Invalid write of size 1 ==31974== at 0x4006ED: main (in /home/andreas/a.out) ==31974== Address 0x521318a is 0 bytes after a block of size 218 alloc'd ==31974== at 0x4C338CF: realloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==31974== by 0x4006DE: main (in /home/andreas/a.out) Andreas. -- Andreas Schwab, sch...@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
