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    Subject[PATCH 5.8 083/124] pipe: Fix memory leaks in create_pipe_files()
    Date
    From: Qian Cai <cai@redhat.com>

    [ Upstream commit 8a018eb55e3ac033592afbcb476b0ffe64465b12 ]

    Calling pipe2() with O_NOTIFICATION_PIPE could results in memory
    leaks unless watch_queue_init() is successful.

    In case of watch_queue_init() failure in pipe2() we are left
    with inode and pipe_inode_info instances that need to be freed. That
    failure exit has been introduced in commit c73be61cede5 ("pipe: Add
    general notification queue support") and its handling should've been
    identical to nearby treatment of alloc_file_pseudo() failures - it
    is dealing with the same situation. As it is, the mainline kernel
    leaks in that case.

    Another problem is that CONFIG_WATCH_QUEUE and !CONFIG_WATCH_QUEUE
    cases are treated differently (and the former leaks just pipe_inode_info,
    the latter - both pipe_inode_info and inode).

    Fixed by providing a dummy wacth_queue_init() in !CONFIG_WATCH_QUEUE
    case and by having failures of wacth_queue_init() handled the same way
    we handle alloc_file_pseudo() ones.

    Fixes: c73be61cede5 ("pipe: Add general notification queue support")
    Signed-off-by: Qian Cai <cai@redhat.com>
    Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    fs/pipe.c | 11 +++++------
    include/linux/watch_queue.h | 6 ++++++
    2 files changed, 11 insertions(+), 6 deletions(-)

    diff --git a/fs/pipe.c b/fs/pipe.c
    index 117db82b10af5..0ac197658a2d6 100644
    --- a/fs/pipe.c
    +++ b/fs/pipe.c
    @@ -894,19 +894,18 @@ int create_pipe_files(struct file **res, int flags)
    {
    struct inode *inode = get_pipe_inode();
    struct file *f;
    + int error;

    if (!inode)
    return -ENFILE;

    if (flags & O_NOTIFICATION_PIPE) {
    -#ifdef CONFIG_WATCH_QUEUE
    - if (watch_queue_init(inode->i_pipe) < 0) {
    + error = watch_queue_init(inode->i_pipe);
    + if (error) {
    + free_pipe_info(inode->i_pipe);
    iput(inode);
    - return -ENOMEM;
    + return error;
    }
    -#else
    - return -ENOPKG;
    -#endif
    }

    f = alloc_file_pseudo(inode, pipe_mnt, "",
    diff --git a/include/linux/watch_queue.h b/include/linux/watch_queue.h
    index 5e08db2adc319..c994d1b2cdbaa 100644
    --- a/include/linux/watch_queue.h
    +++ b/include/linux/watch_queue.h
    @@ -122,6 +122,12 @@ static inline void remove_watch_list(struct watch_list *wlist, u64 id)
    */
    #define watch_sizeof(STRUCT) (sizeof(STRUCT) << WATCH_INFO_LENGTH__SHIFT)

    +#else
    +static inline int watch_queue_init(struct pipe_inode_info *pipe)
    +{
    + return -ENOPKG;
    +}
    +
    #endif

    #endif /* _LINUX_WATCH_QUEUE_H */
    --
    2.25.1


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