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| author | Pavel Begunkov <asml.silence@gmail.com> | 2021-04-01 15:43:54 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-04-11 19:30:34 -0600 |
| commit | 75769e3f7357171dbe040a5ed55445c2642295d1 (patch) | |
| tree | 8e63709e8e711ec094cb354ba764ce2eaec49cc7 /fs/io_uring.c | |
| parent | 0aec38fda2b6e36c0b066a87ff727ace3666cade (diff) | |
| download | lwn-75769e3f7357171dbe040a5ed55445c2642295d1.tar.gz lwn-75769e3f7357171dbe040a5ed55445c2642295d1.zip | |
io_uring: improve import_fixed overflow checks
Replace a hand-coded overflow check with a specialised function. Even
though compilers are smart enough to generate identical binary (i.e.
check carry bit), but it's more foolproof and conveys the intention
better.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e437dcdc929bacbb6f11a4824ecbbf17225cb82a.1617287883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index f53d93261e2b..e6508b19e19e 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2785,8 +2785,8 @@ static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter) size_t len = req->rw.len; struct io_mapped_ubuf *imu; u16 index, buf_index = req->buf_index; + u64 buf_end, buf_addr = req->rw.addr; size_t offset; - u64 buf_addr; if (unlikely(buf_index >= ctx->nr_user_bufs)) return -EFAULT; @@ -2794,11 +2794,10 @@ static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter) imu = &ctx->user_bufs[index]; buf_addr = req->rw.addr; - /* overflow */ - if (buf_addr + len < buf_addr) + if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end))) return -EFAULT; /* not inside the mapped region */ - if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len) + if (buf_addr < imu->ubuf || buf_end > imu->ubuf + imu->len) return -EFAULT; /* |