| Message ID | 20240724170544.11372-1-n.zhandarovich@fintech.ru (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 47f268f33dff4a5e31541a990dc09f116f80e61c |
| Headers | show |
| Series | [f2fs-dev] f2fs: prevent possible int overflow in dir_block_index() | expand |
On 2024/7/25 1:05, Nikita Zhandarovich wrote: > The result of multiplication between values derived from functions > dir_buckets() and bucket_blocks() *could* technically reach > 2^30 * 2^2 = 2^32. > > While unlikely to happen, it is prudent to ensure that it will not > lead to integer overflow. Thus, use mul_u32_u32() as it's more > appropriate to mitigate the issue. > > Found by Linux Verification Center (linuxtesting.org) with static > analysis tool SVACE. > > Fixes: 3843154598a0 ("f2fs: introduce large directory support") > Cc: stable@vger.kernel.org > Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru> Reviewed-by: Chao Yu <chao@kernel.org> Thanks,
Hello: This patch was applied to jaegeuk/f2fs.git (dev) by Jaegeuk Kim <jaegeuk@kernel.org>: On Wed, 24 Jul 2024 10:05:44 -0700 you wrote: > The result of multiplication between values derived from functions > dir_buckets() and bucket_blocks() *could* technically reach > 2^30 * 2^2 = 2^32. > > While unlikely to happen, it is prudent to ensure that it will not > lead to integer overflow. Thus, use mul_u32_u32() as it's more > appropriate to mitigate the issue. > > [...] Here is the summary with links: - [f2fs-dev] f2fs: prevent possible int overflow in dir_block_index() https://git.kernel.org/jaegeuk/f2fs/c/47f268f33dff You are awesome, thank you!
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index cbd7a5e96a37..14900ca8a9ff 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -166,7 +166,8 @@ static unsigned long dir_block_index(unsigned int level, unsigned long bidx = 0; for (i = 0; i < level; i++) - bidx += dir_buckets(i, dir_level) * bucket_blocks(i); + bidx += mul_u32_u32(dir_buckets(i, dir_level), + bucket_blocks(i)); bidx += idx * bucket_blocks(level); return bidx; }
The result of multiplication between values derived from functions dir_buckets() and bucket_blocks() *could* technically reach 2^30 * 2^2 = 2^32. While unlikely to happen, it is prudent to ensure that it will not lead to integer overflow. Thus, use mul_u32_u32() as it's more appropriate to mitigate the issue. Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE. Fixes: 3843154598a0 ("f2fs: introduce large directory support") Cc: stable@vger.kernel.org Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru> --- fs/f2fs/dir.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)