[BUG] Buffer overflow in sf_putints, sf_putfloats (And suggestions)

[cplusv2023]

🐛 Bug report

Programs (e.g. sflpef, sfhpef) that uses sf_putints and sf_putfloats may occur buffer overflow.

In (current version) api/c/file.c, Lines 998, 1000, 1037, 1039:

(L998 as example:)

// v defined as char val[1024], *v=val
// Some iterations of i
/* L998 */ v += snprintf(v,1024,"%g,",par[i]);

the pointer v moves forwards when iteration goes on, while the length of snprintf always being 1024, this could lead to buffer overlow.

To Reproduce

Steps to reproduce the behavior:

1. Use some programs that employs sf_putints (or sf_putfloats)
2. It happens.

Screenshots
Before debugging:

Debugging:

Desktop (please complete the following information):

• OS: Ubuntu 24.04.02 LTS
• GCC Version: (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0

Suggestions

Use a smaller length in snprintf, like:

// Some iterations of i
v+=snprintf(v,1023-i*11,"%g,",par[i]);
//...
snprintf(v,1023-n*11,"%d",par[n-1]);
// I use 11 because maxlen 2147483647 = 10 digits plus 1 char ','
// Actually maybe some const value like 20 is ok.
// Or if the list is overlength, use a dynamic char array.