Program received signal SIGSEGV, Segmentation fault. at fbitstr_tell in bitstr.c

[ambrosecm]

Desctiption

When I used the bitstr_tell function to handle a specific input, a segmentation fault (SEGV) was triggered at fbitstr_tell in bitstr.c

ffjpeg/src/bitstr.c

Lines 233 to 243 in caade60

	long bitstr_tell(void *stream)
	{
	int type;
	if (!stream) return EOF;
	type = *(int*)stream;
	switch (type) {
	case BITSTR_MEM : return mbitstr_tell(stream);
	case BITSTR_FILE: return fbitstr_tell(stream);
	}
	return EOF;
	}

ffjpeg/src/bitstr.c

Lines 149 to 154 in caade60

	static long fbitstr_tell(void *stream)
	{
	FBITSTR *context = (FBITSTR*)stream;
	if (!context || !context->fp) return EOF;
	return ftell(context->fp);
	}

Test Environment

Ubuntu 22.04.1, 64bit
ffjpeg(master caade60)
program source file

How to trigger

Download the poc file , program and run the following cmd:

 $ ./fbitstr_tell ./poc

Detail

GDB report

(gdb) r
Starting program: /data/ambrose/output/ffjpeg_temperature_test/ffjpeg_deepseek/crashes/bitstr.c/bitstr_tell/fbitstr_tell/fbitstr_tell output/default/crashes/id:000000,sig:11,src:000006,time:629165,execs:433715,op:havoc,rep:1
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7c7fd4d in __GI__IO_ftell (fp=0x3030303030303030) at ./libio/ioftell.c:37
37      ./libio/ioftell.c: No such file or directory.
(gdb) bt
#0  0x00007ffff7c7fd4d in __GI__IO_ftell (fp=0x3030303030303030) at ./libio/ioftell.c:37
#1  0x000055555555597d in fbitstr_tell ()
#2  0x0000555555555c3f in bitstr_tell ()
#3  0x0000555555555498 in main (argc=2, argv=0x7fffffffdc78)
    at /home/ambrose/vsproject/HIMFuzz/harness/output/ffjpeg_deepseek/harness/code/bitstr.c/bitstr_tell/fbitstr_tell.c:36