diff mbox series

[201/262] zram: off by one in read_block_state()

Message ID 20211105204512.OEBIB2O7B%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [001/262] scripts/spelling.txt: add more spellings to spelling.txt | expand

Commit Message

Andrew Morton Nov. 5, 2021, 8:45 p.m. UTC 
From: Dan Carpenter <dan.carpenter@oracle.com>
Subject: zram: off by one in read_block_state()

snprintf() returns the number of bytes it would have printed if there were
space.  But it does not count the NUL terminator.  So that means that if
"count == copied" then this has already overflowed by one character.

This bug likely isn't super harmful in real life.

Link: https://lkml.kernel.org/r/20210916130404.GA25094@kili
Fixes: c0265342bff4 ("zram: introduce zram memory tracking")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/block/zram/zram_drv.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

--- a/drivers/block/zram/zram_drv.c~zram-off-by-one-in-read_block_state
+++ a/drivers/block/zram/zram_drv.c
@@ -910,7 +910,7 @@  static ssize_t read_block_state(struct f
 			zram_test_flag(zram, index, ZRAM_HUGE) ? 'h' : '.',
 			zram_test_flag(zram, index, ZRAM_IDLE) ? 'i' : '.');
 
-		if (count < copied) {
+		if (count <= copied) {
 			zram_slot_unlock(zram, index);
 			break;
 		}