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Use proper buffer size in tt_user.c's digit_suffix #582

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Use proper buffer size in tt_user.c's digit_suffix #582

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Use proper buffer size in tt_user.c's digit_suffix 
Modern Ubuntu (e.g. GitHub Actions' `ubuntu-latest`), among other
distros, compiles with `-D_FORTIFY_SOURCE=3` which does neat things like
checking `strlcpy` won't overflow.

`tt_user_s` has a `char digit_suffix[3+1]`, so when attempting to
`strlcpy` into it with length 5, this triggers a buffer overflow error
for safety reasons (even though the source string only has length 4)

Let's instead pass a size to `digit_suffix` and use that.
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@doismellburning
doismellburning committed Jul 19, 2025
commit f8e0994de511b05a01861a4b822e83de92320951
6 changes: 3 additions & 3 deletions src/tt_user.c
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Original file line number Diff line number Diff line change
Expand Up @@ -429,13 +429,13 @@ static int corral_slot (void)
*
*----------------------------------------------------------------*/

static void digit_suffix (char *callsign, char *suffix)
static void digit_suffix (char *callsign, char *suffix, size_t suffix_len)
{
char two_key[50];
char *t;


strlcpy (suffix, "000", 5); // TODO: should have proper size
strlcpy (suffix, "000", suffix_len);
tt_text_to_two_key (callsign, 0, two_key);
for (t = two_key; *t != '\0'; t++) {
if (isdigit(*t)) {
Expand Down Expand Up @@ -515,7 +515,7 @@ int tt_user_heard (char *callsign, int ssid, char overlay, char symbol, char *lo
tt_user[i].ssid = ssid;
tt_user[i].overlay = overlay;
tt_user[i].symbol = symbol;
digit_suffix(tt_user[i].callsign, tt_user[i].digit_suffix);
digit_suffix(tt_user[i].callsign, tt_user[i].digit_suffix, sizeof(tt_user[i].digit_suffix));
strlcpy (tt_user[i].loc_text, loc_text, sizeof(tt_user[i].loc_text));

if (latitude != G_UNKNOWN && longitude != G_UNKNOWN) {
Expand Down