lkml.org 
[lkml]   [2020]   [Jul]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 20/23] sysctl: Convert to iter interfaces
    Date
    From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

    Using the read_iter/write_iter interfaces allows for in-kernel users
    to set sysctls without using set_fs(). Also, the buffer is a string,
    so give it the real type of 'char *', not void *.

    Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
    ---
    fs/proc/proc_sysctl.c | 44 ++++++++++++++++++--------------------
    include/linux/bpf-cgroup.h | 2 +-
    kernel/bpf/cgroup.c | 2 +-
    3 files changed, 23 insertions(+), 25 deletions(-)

    diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
    index 6c1166ccdaea57..9f6b9c3e3fdaf5 100644
    --- a/fs/proc/proc_sysctl.c
    +++ b/fs/proc/proc_sysctl.c
    @@ -12,6 +12,7 @@
    #include <linux/cred.h>
    #include <linux/namei.h>
    #include <linux/mm.h>
    +#include <linux/uio.h>
    #include <linux/module.h>
    #include <linux/bpf-cgroup.h>
    #include <linux/mount.h>
    @@ -540,13 +541,14 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
    return err;
    }

    -static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf,
    - size_t count, loff_t *ppos, int write)
    +static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter,
    + int write)
    {
    - struct inode *inode = file_inode(filp);
    + struct inode *inode = file_inode(iocb->ki_filp);
    struct ctl_table_header *head = grab_header(inode);
    struct ctl_table *table = PROC_I(inode)->sysctl_entry;
    - void *kbuf;
    + size_t count = iov_iter_count(iter);
    + char *kbuf;
    ssize_t error;

    if (IS_ERR(head))
    @@ -569,32 +571,30 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf,
    error = -ENOMEM;
    if (count >= KMALLOC_MAX_SIZE)
    goto out;
    + kbuf = kzalloc(count + 1, GFP_KERNEL);
    + if (!kbuf)
    + goto out;

    if (write) {
    - kbuf = memdup_user_nul(ubuf, count);
    - if (IS_ERR(kbuf)) {
    - error = PTR_ERR(kbuf);
    - goto out;
    - }
    - } else {
    - kbuf = kzalloc(count, GFP_KERNEL);
    - if (!kbuf)
    + error = -EFAULT;
    + if (!copy_from_iter_full(kbuf, count, iter))
    goto out;
    + kbuf[count] = '\0';
    }

    error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count,
    - ppos);
    + &iocb->ki_pos);
    if (error)
    goto out_free_buf;

    /* careful: calling conventions are nasty here */
    - error = table->proc_handler(table, write, kbuf, &count, ppos);
    + error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos);
    if (error)
    goto out_free_buf;

    if (!write) {
    error = -EFAULT;
    - if (copy_to_user(ubuf, kbuf, count))
    + if (copy_to_iter(kbuf, count, iter) < count)
    goto out_free_buf;
    }

    @@ -607,16 +607,14 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf,
    return error;
    }

    -static ssize_t proc_sys_read(struct file *filp, char __user *buf,
    - size_t count, loff_t *ppos)
    +static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter)
    {
    - return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
    + return proc_sys_call_handler(iocb, iter, 0);
    }

    -static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
    - size_t count, loff_t *ppos)
    +static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter)
    {
    - return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
    + return proc_sys_call_handler(iocb, iter, 1);
    }

    static int proc_sys_open(struct inode *inode, struct file *filp)
    @@ -853,8 +851,8 @@ static int proc_sys_getattr(const struct path *path, struct kstat *stat,
    static const struct file_operations proc_sys_file_operations = {
    .open = proc_sys_open,
    .poll = proc_sys_poll,
    - .read = proc_sys_read,
    - .write = proc_sys_write,
    + .read_iter = proc_sys_read,
    + .write_iter = proc_sys_write,
    .llseek = default_llseek,
    };

    diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
    index c66c545e161a60..f81d3b3752f919 100644
    --- a/include/linux/bpf-cgroup.h
    +++ b/include/linux/bpf-cgroup.h
    @@ -132,7 +132,7 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,

    int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
    struct ctl_table *table, int write,
    - void **buf, size_t *pcount, loff_t *ppos,
    + char **buf, size_t *pcount, loff_t *ppos,
    enum bpf_attach_type type);

    int __cgroup_bpf_run_filter_setsockopt(struct sock *sock, int *level,
    diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
    index ac53102e244a7a..81dcf15990ebe1 100644
    --- a/kernel/bpf/cgroup.c
    +++ b/kernel/bpf/cgroup.c
    @@ -1202,7 +1202,7 @@ const struct bpf_verifier_ops cg_dev_verifier_ops = {
    */
    int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,
    struct ctl_table *table, int write,
    - void **buf, size_t *pcount, loff_t *ppos,
    + char **buf, size_t *pcount, loff_t *ppos,
    enum bpf_attach_type type)
    {
    struct bpf_sysctl_kern ctx = {
    --
    2.26.2
    \
     
     \ /
      Last update: 2020-07-01 22:24    [W:4.233 / U:0.096 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site