diff mbox series

[v2,01/24] ewah/ewah_bitmap.c: grow buffer past 1

Message ID 07054ff8ee43c4361c472e40b72f767107f66ed8.1605649533.git.me@ttaylorr.com (mailing list archive)
State Superseded
Headers show
Series pack-bitmap: bitmap generation improvements | expand

Commit Message

Taylor Blau Nov. 17, 2020, 9:46 p.m. UTC 
When the buffer size is exactly 1, we fail to grow it properly, since
the integer truncation means that 1 * 3 / 2 = 1. This can cause a bad
write on the line below.

Bandaid this by first padding the buffer by 16, and then growing it.
This still allows old blocks to fit into new ones, but fixes the case
where the block size equals 1.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 ewah/ewah_bitmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/ewah/ewah_bitmap.c b/ewah/ewah_bitmap.c
index d59b1afe3d..3fae04ad00 100644
--- a/ewah/ewah_bitmap.c
+++ b/ewah/ewah_bitmap.c
@@ -45,7 +45,7 @@  static inline void buffer_grow(struct ewah_bitmap *self, size_t new_size)
 static inline void buffer_push(struct ewah_bitmap *self, eword_t value)
 {
 	if (self->buffer_size + 1 >= self->alloc_size)
-		buffer_grow(self, self->buffer_size * 3 / 2);
+		buffer_grow(self, (self->buffer_size + 16) * 3 / 2);
 
 	self->buffer[self->buffer_size++] = value;
 }