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input: give up when the capacity of the keystroke buffer overflows

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In theory, the 'size_t' of 'capacity' could be just two bytes, which
means the keystroke buffer would overflow for pastes that are larger
than 32 kilobytes -- which are unlikely to occur, but... possible.
However, previously there was *no* overflow check when extending the
keystroke buffer (only when trying to put back a key code), so this
check is an improvement.

(On a regular machine, 'size_t' is at least four bytes, which means
the keystroke buffer would overflow at 2 gigabytes.  Such a paste
is extremely unlikely to occur, so this check is really a no-op.)
This commit is contained in:
Benno Schulenberg 2022-09-25 09:57:05 +02:00
parent 3922b531a8
commit e4abef5768
1 changed files with 3 additions and 4 deletions
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7
src/winio.c
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@ -143,6 +143,9 @@ void run_macro(void)
/* Allocate the requested space for the keystroke buffer. */ /* Allocate the requested space for the keystroke buffer. */
void reserve_space_for(size_t newsize) void reserve_space_for(size_t newsize)
{ {
if (newsize < capacity)
die(_("Too much input at once\n"));
key_buffer = nrealloc(key_buffer, newsize * sizeof(int)); key_buffer = nrealloc(key_buffer, newsize * sizeof(int));
nextcodes = key_buffer; nextcodes = key_buffer;
capacity = newsize; capacity = newsize;
@ -324,10 +327,6 @@ size_t waiting_keycodes(void)
/* Add the given keycode to the front of the keystroke buffer. */ /* Add the given keycode to the front of the keystroke buffer. */
void put_back(int keycode) void put_back(int keycode)
{ {
/* If the keystroke buffer is at maximum capacity, don't add anything. */
if (waiting_codes + 1 < waiting_codes)
return;
/* If there is no room at the head of the keystroke buffer, make room. */ /* If there is no room at the head of the keystroke buffer, make room. */
if (nextcodes == key_buffer) { if (nextcodes == key_buffer) {
if (waiting_codes == capacity) if (waiting_codes == capacity)