Raphael S.Carvalho
2013-Sep-16 00:50 UTC
[syslinux] [PATCH 1/2] com32: Fix bugs on cmd_reverse_search (Triple fault dimension)
cmd_reverse_search has a bug that the variable cursor is updated even if a command wasn't found. If this happens, and the next key falls into the default case, memmove's size parameter would be a negative number. This bug can be reproduced by doing the following: On cmd_reverse_search (ctrl-r), type multiple keys at the same time. 'Enjoy' the triple fault and a screen of random colors. There is also a small bug that turns the task of using ctrl-R on the very first command impossible. Previously, this command was discarted. Signed-off-by: Raphael S.Carvalho <raphael.scarv at gmail.com> --- com32/elflink/ldlinux/cli.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) diff --git a/com32/elflink/ldlinux/cli.c b/com32/elflink/ldlinux/cli.c index 7c4f14c..b70224a 100644 --- a/com32/elflink/ldlinux/cli.c +++ b/com32/elflink/ldlinux/cli.c @@ -89,10 +89,14 @@ static const char * cmd_reverse_search(int *cursor, clock_t *kbd_to, break; } - while (!list_is_last(&last_found->list, &cli_history_head)) { + while (last_found) { p = strstr(last_found->command, buf); if (p) break; + + if (list_is_last(&last_found->list, &cli_history_head)) + break; + last_found = list_entry(last_found->list.next, typeof(*last_found), list); } @@ -391,7 +395,7 @@ const char *edit_cmdline(const char *input, int top /*, int width */ , len = strlen(cmdline); } else { cmdline[0] = '\0'; - len = 0; + cursor = len = 0; } redraw = 1; } @@ -441,6 +445,9 @@ const char *edit_cmdline(const char *input, int top /*, int width */ , } prev_len++; } else { + if (cursor > len) + return NULL; + memmove(cmdline + cursor + 1, cmdline + cursor, len - cursor + 1); cmdline[cursor++] = key; -- 1.7.2.5