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| author | Pavel Begunkov <asml.silence@gmail.com> | 2021-04-15 13:07:39 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-04-17 19:20:07 -0600 |
| commit | 38134ada0ceea3e848fe993263c0ff6207fd46e7 (patch) | |
| tree | 2401b532fc9a60889a0a29d5736f312d91f2c6c9 /fs/io_uring.c | |
| parent | c82d5bc703825a47af5c600e82e1e0c1db49e036 (diff) | |
| download | lwn-38134ada0ceea3e848fe993263c0ff6207fd46e7.tar.gz lwn-38134ada0ceea3e848fe993263c0ff6207fd46e7.zip | |
io_uring: fix overflows checks in provide buffers
Colin reported before possible overflow and sign extension problems in
io_provide_buffers_prep(). As Linus pointed out previous attempt did nothing
useful, see d81269fecb8ce ("io_uring: fix provide_buffers sign extension").
Do that with help of check_<op>_overflow helpers. And fix struct
io_provide_buf::len type, as it doesn't make much sense to keep it
signed.
Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: efe68c1ca8f49 ("io_uring: validate the full range of provided buffers for access")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/46538827e70fce5f6cdb50897cff4cacc490f380.1618488258.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 | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 81bfe91aed0a..bae13811d2f3 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -626,7 +626,7 @@ struct io_splice { struct io_provide_buf { struct file *file; __u64 addr; - __s32 len; + __u32 len; __u32 bgid; __u16 nbufs; __u16 bid; @@ -3918,7 +3918,7 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags) static int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { - unsigned long size; + unsigned long size, tmp_check; struct io_provide_buf *p = &req->pbuf; u64 tmp; @@ -3932,6 +3932,12 @@ static int io_provide_buffers_prep(struct io_kiocb *req, p->addr = READ_ONCE(sqe->addr); p->len = READ_ONCE(sqe->len); + if (check_mul_overflow((unsigned long)p->len, (unsigned long)p->nbufs, + &size)) + return -EOVERFLOW; + if (check_add_overflow((unsigned long)p->addr, size, &tmp_check)) + return -EOVERFLOW; + size = (unsigned long)p->len * p->nbufs; if (!access_ok(u64_to_user_ptr(p->addr), size)) return -EFAULT; |