Skip to content

fix: prevent overflow in minmea_scan 's' format specifier #98

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
dwilliams27 wants to merge 1 commit into
base: master
Choose a base branch
from
Open

fix: prevent overflow in minmea_scan 's' format specifier #98

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 4 additions & 1 deletion minmea.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -230,10 +230,13 @@ bool minmea_scan(const char *sentence, const char *format, ...)

case 's': { // String value (char *).
char *buf = va_arg(ap, char *);
int len = 0;

if (field) {
while (minmea_isfield(*field))
while (minmea_isfield(*field) && len < MINMEA_MAX_SENTENCE_LENGTH - 1) {
*buf++ = *field++;
len++;
}
}

*buf = '\0';
Expand Down
18 changes: 18 additions & 0 deletions tests.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -285,6 +285,23 @@ START_TEST(test_minmea_scan_s)
}
END_TEST

START_TEST(test_minmea_scan_s_overflow)
{
/* Oversized field must be truncated, not overflow the destination. */
char oversized[MINMEA_MAX_SENTENCE_LENGTH * 2];
memset(oversized, 'A', sizeof(oversized) - 1);
oversized[sizeof(oversized) - 1] = '\0';

char value[MINMEA_MAX_SENTENCE_LENGTH];
memset(value, 0, sizeof(value));

ck_assert(minmea_scan(oversized, "s", value) == true);
ck_assert_int_eq((int)strlen(value), MINMEA_MAX_SENTENCE_LENGTH - 1);
for (int i = 0; i < MINMEA_MAX_SENTENCE_LENGTH - 1; i++)
ck_assert_int_eq(value[i], 'A');
}
END_TEST

START_TEST(test_minmea_scan_t)
{
union minmea_type type;
Expand Down Expand Up @@ -1223,6 +1240,7 @@ static Suite *minmea_suite(void)
tcase_add_test(tc_scan, test_minmea_scan_f);
tcase_add_test(tc_scan, test_minmea_scan_i);
tcase_add_test(tc_scan, test_minmea_scan_s);
tcase_add_test(tc_scan, test_minmea_scan_s_overflow);
tcase_add_test(tc_scan, test_minmea_scan_t);
tcase_add_test(tc_scan, test_minmea_scan_t_str);
tcase_add_test(tc_scan, test_minmea_scan_D);
Expand Down