>From 93775b67bbc3e4f761808b216bc76127f89f9ad7 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Wed, 24 Jun 2020 14:31:08 -0400 Subject: [PATCH 2/2] sysctl: Convert to iter interfaces To: hch@lst.de 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) --- 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 6c1166ccdaea..9f6b9c3e3fda 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -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 c66c545e161a..f81d3b3752f9 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 4d76f16524cc..45a918fc573d 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 = { -- 2.27.0