Changeset ff7e5c9 in gitlab

Timestamp:

Dec 15, 2020, 7:25:15 PM (3 years ago)

Author:

Jordan Christiansen <xordspar0@…>

Branches:

master

Children:

32ec828

Parents:

6f94186

git-author:

Jordan Christiansen <xordspar0@…> (15/12/2020 19:06:34)

git-committer:

Jordan Christiansen <xordspar0@…> (15/12/2020 19:25:15)

Message:

Prevent a file path buffer overrun

If a filename passed from the command line arguments is ever longer than
the current working directory (and it usually is longer), strcpy will
overrun the working directory buffer. This usually doesn't cause a crash
right away, but it caused weird bugs for me, like an assertion failure
in free() when trying to free the buffer later:

free(): invalid next size (fast)

Valgrind helped me track down the cause:

$ valgrind bin/grafx2-sdl ~/Projects/kind-of-longish-directory-name/file.gif

...

==116375== Invalid write of size 1
==116375== at 0x483DDE6: strcpy (vg_replace_strmem.c:511)
==116375== by 0x1265B2: Init_program (main.c:1104)
==116375== by 0x12704F: main (main.c:1536)
==116375== Address 0x5534a81 is 21 bytes after a block of size 28 alloc'd
==116375== at 0x483CD7B: realloc (vg_replace_malloc.c:834)
==116375== by 0x4E70F3F: getcwd (in /usr/lib/libc-2.32.so)
==116375== by 0x17277E: Get_current_directory (io.c:1096)
==116375== by 0x125B02: Init_program (main.c:655)
==116375== by 0x12704F: main (main.c:1536)

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