Memory troubles in a DIY gcc csv reader - gcc

Question

Writing some code to reformat some CSV data.
It's been a while since I was working in C and doing programming with memory management this raw, and I don't have a lot of experience with many of the tools for debugging memory allocation.
Diving right in I found some forum posts suggesting compiling like this to figure out where the segmentation fault was originating.
gcc -o CSVreader_v0.0-memcheck -static-libasan -O -g -fsanitize=address -fno-omit-frame-pointer -Wall -Wno-unused-result CSVreader.c
My only problem is I have no idea how to interpret the output can someone help walk me through this or point me to a guide on what all this means.
==9474==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000000015 at pc 0x7f1a330533a6 bp 0x7ffedc0840d0 sp 0x7ffedc083878
WRITE of size 6 at 0x602000000015 thread T0
#0 0x7f1a330533a5 (/usr/lib/x86_64-linux-gnu/libasan.so.4+0x663a5)
#1 0x55a46460155a in parseRow (/home/kodachi/workspace/Tactical Engram/CSVreader_v0.0+0x155a)
#2 0x55a4646018e5 in parseCSV (/home/kodachi/workspace/Tactical Engram/CSVreader_v0.0+0x18e5)
#3 0x55a464601c7b in main (/home/kodachi/workspace/Tactical Engram/CSVreader_v0.0+0x1c7b)
#4 0x7f1a32e220b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
#5 0x55a46460122d in _start (/home/kodachi/workspace/Tactical Engram/CSVreader_v0.0+0x122d)
0x602000000015 is located 0 bytes to the right of 5-byte region [0x602000000010,0x602000000015)
allocated by thread T0 here:
#0 0x7f1a330cbb40 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb40)
#1 0x55a4646014f1 in parseRow (/home/kodachi/workspace/Tactical Engram/CSVreader_v0.0+0x14f1)
#2 0x55a4646018e5 in parseCSV (/home/kodachi/workspace/Tactical Engram/CSVreader_v0.0+0x18e5)
#3 0x55a464601c7b in main (/home/kodachi/workspace/Tactical Engram/CSVreader_v0.0+0x1c7b)
#4 0x7f1a32e220b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
SUMMARY: AddressSanitizer: heap-buffer-overflow (/usr/lib/x86_64-linux-gnu/libasan.so.4+0x663a5)
Shadow bytes around the buggy address:
0x0c047fff7fb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c047fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c047fff8000: fa fa[05]fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8010: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c047fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
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
==9474==ABORTING
I'd like to understand what all this means but equally if someone can point me to how I can get a more human readable output that would also be helpful, I tried valgrind, but I'm not sure I was using it correctly.
Right now my code is taking the first line of the csv file using
fscanf(fp, "%[^\n]\n", line_buffer);
with char* line_buffer and char** hStrings to store the column headers, I pass &linebuffer and &hStrings into the following function to parse the column headers in the 'line_buffer' string into 'hStrings' with the delimiting character being '|'.
/**
* Split str around the '|' character and store the data in dStr
**/
int parseRow(char** str, char*** dStr)
{
unsigned int columns = 0;
char* col;
printf("Splitting: %s\n", *str);
col = strsep(str, "|");
while(col != NULL && hasPrint(col, 0, strlen(col)))
{
printf("\n");
(*dStr)[columns] = malloc(strlen(col)*sizeof(char));
strcpy((*dStr)[columns], col);
columns++;
col = strsep(str, "|");
}
//printf("\n");
printf("counted: %d columns\n", columns);
return columns;
}
Before I was using `-fsanitize=address' the program would run this part correctly and a segmentation fault would occur later when I was parsing the rows of data, not the column headers. Now it generates the output I provided as it is working on the first row containing the headers. Not sure if that helps understand what's going on here.