lkml.org 
[lkml]   [2021]   [May]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.10 344/530] io_uring: fix overflows checks in provide buffers
    Date
    From: Pavel Begunkov <asml.silence@gmail.com>

    [ Upstream commit 38134ada0ceea3e848fe993263c0ff6207fd46e7 ]

    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>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    fs/io_uring.c | 10 ++++++++--
    1 file changed, 8 insertions(+), 2 deletions(-)

    diff --git a/fs/io_uring.c b/fs/io_uring.c
    index 55e214defb42..369ec81033d6 100644
    --- a/fs/io_uring.c
    +++ b/fs/io_uring.c
    @@ -527,7 +527,7 @@ struct io_splice {
    struct io_provide_buf {
    struct file *file;
    __u64 addr;
    - __s32 len;
    + __u32 len;
    __u32 bgid;
    __u16 nbufs;
    __u16 bid;
    @@ -3996,7 +3996,7 @@ static int io_remove_buffers(struct io_kiocb *req, bool force_nonblock,
    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;

    @@ -4010,6 +4010,12 @@ 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;
    --
    2.30.2


    \
     
     \ /
      Last update: 2021-05-12 19:01    [W:2.559 / U:0.820 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site