Messages in this thread Patch in this message | | | From | Sergey Shtylyov <> | Subject | [PATCH] f2fs: data: fix possible overflow in check_swap_activate() | Date | Wed, 25 Oct 2023 23:20:19 +0300 |
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In check_swap_activate(), if the *while* loop exits early (0- or 1-page long swap file), an overflow happens while calculating the value of the span parameter as the lowest_pblock variable ends up being greater than the highest_pblock variable. Let's set *span to 0 in this case...
Found by Linux Verification Center (linuxtesting.org) with the SVACE static analysis tool.
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> --- This patch is against the 'master' branch of Jaegeuk Kim's F2FS repo...
fs/f2fs/data.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 916e317ac925..342cb0d5056d 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -4047,7 +4047,10 @@ static int check_swap_activate(struct swap_info_struct *sis, cur_lblock += nr_pblocks; } ret = nr_extents; - *span = 1 + highest_pblock - lowest_pblock; + if (lowest_pblock <= highest_pblock) + *span = 1 + highest_pblock - lowest_pblock; + else + *span = 0; if (cur_lblock == 0) cur_lblock = 1; /* force Empty message */ sis->max = cur_lblock; -- 2.26.3
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