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authorLinus Torvalds <torvalds@linux-foundation.org>2020-07-10 09:45:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-07-10 09:45:15 -0700
commitb1b11d0063aab28aaf65f63cff56470bc01dc290 (patch)
tree11c80d3317990b4bc7d1128c63fc63f444deca3b
parent1bfde037425d91d1d615d30ec362f5f5c1ca0dd2 (diff)
parent775802c0571fb438cd4f6548a323f9e4cb89f5aa (diff)
Merge tag 'cleanup-kernel_read_write' of git://git.infradead.org/users/hch/misc
Pull in-kernel read and write op cleanups from Christoph Hellwig: "Cleanup in-kernel read and write operations Reshuffle the (__)kernel_read and (__)kernel_write helpers, and ensure all users of in-kernel file I/O use them if they don't use iov_iter based methods already. The new WARN_ONs in combination with syzcaller already found a missing input validation in 9p. The fix should be on your way through the maintainer ASAP". [ This is prep-work for the real changes coming 5.9 ] * tag 'cleanup-kernel_read_write' of git://git.infradead.org/users/hch/misc: fs: remove __vfs_read fs: implement kernel_read using __kernel_read integrity/ima: switch to using __kernel_read fs: add a __kernel_read helper fs: remove __vfs_write fs: implement kernel_write using __kernel_write fs: check FMODE_WRITE in __kernel_write fs: unexport __kernel_write bpfilter: switch to kernel_write autofs: switch to kernel_write cachefiles: switch to kernel_write
-rw-r--r--fs/autofs/waitq.c2
-rw-r--r--fs/cachefiles/rdwr.c2
-rw-r--r--fs/read_write.c131
-rw-r--r--include/linux/fs.h2
-rw-r--r--net/bpfilter/bpfilter_kern.c2
-rw-r--r--security/integrity/iint.c14
6 files changed, 80 insertions, 73 deletions
diff --git a/fs/autofs/waitq.c b/fs/autofs/waitq.c
index b04c528b19d3..74c886f7c51c 100644
--- a/fs/autofs/waitq.c
+++ b/fs/autofs/waitq.c
@@ -53,7 +53,7 @@ static int autofs_write(struct autofs_sb_info *sbi,
mutex_lock(&sbi->pipe_mutex);
while (bytes) {
- wr = __kernel_write(file, data, bytes, &file->f_pos);
+ wr = kernel_write(file, data, bytes, &file->f_pos);
if (wr <= 0)
break;
data += wr;
diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index e7726f5f1241..3080cda9e824 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -937,7 +937,7 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page)
}
data = kmap(page);
- ret = __kernel_write(file, data, len, &pos);
+ ret = kernel_write(file, data, len, &pos);
kunmap(page);
fput(file);
if (ret != len)
diff --git a/fs/read_write.c b/fs/read_write.c
index bbfa9b12b15e..4fb797822567 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -419,28 +419,42 @@ static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo
return ret;
}
-ssize_t __vfs_read(struct file *file, char __user *buf, size_t count,
- loff_t *pos)
+ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
{
+ mm_segment_t old_fs = get_fs();
+ ssize_t ret;
+
+ if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ)))
+ return -EINVAL;
+ if (!(file->f_mode & FMODE_CAN_READ))
+ return -EINVAL;
+
+ if (count > MAX_RW_COUNT)
+ count = MAX_RW_COUNT;
+ set_fs(KERNEL_DS);
if (file->f_op->read)
- return file->f_op->read(file, buf, count, pos);
+ ret = file->f_op->read(file, (void __user *)buf, count, pos);
else if (file->f_op->read_iter)
- return new_sync_read(file, buf, count, pos);
+ ret = new_sync_read(file, (void __user *)buf, count, pos);
else
- return -EINVAL;
+ ret = -EINVAL;
+ set_fs(old_fs);
+ if (ret > 0) {
+ fsnotify_access(file);
+ add_rchar(current, ret);
+ }
+ inc_syscr(current);
+ return ret;
}
ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
{
- mm_segment_t old_fs;
- ssize_t result;
+ ssize_t ret;
- old_fs = get_fs();
- set_fs(KERNEL_DS);
- /* The cast to a user pointer is valid due to the set_fs() */
- result = vfs_read(file, (void __user *)buf, count, pos);
- set_fs(old_fs);
- return result;
+ ret = rw_verify_area(READ, file, pos, count);
+ if (ret)
+ return ret;
+ return __kernel_read(file, buf, count, pos);
}
EXPORT_SYMBOL(kernel_read);
@@ -456,17 +470,22 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
return -EFAULT;
ret = rw_verify_area(READ, file, pos, count);
- if (!ret) {
- if (count > MAX_RW_COUNT)
- count = MAX_RW_COUNT;
- ret = __vfs_read(file, buf, count, pos);
- if (ret > 0) {
- fsnotify_access(file);
- add_rchar(current, ret);
- }
- inc_syscr(current);
- }
+ if (ret)
+ return ret;
+ if (count > MAX_RW_COUNT)
+ count = MAX_RW_COUNT;
+ if (file->f_op->read)
+ ret = file->f_op->read(file, buf, count, pos);
+ else if (file->f_op->read_iter)
+ ret = new_sync_read(file, buf, count, pos);
+ else
+ ret = -EINVAL;
+ if (ret > 0) {
+ fsnotify_access(file);
+ add_rchar(current, ret);
+ }
+ inc_syscr(current);
return ret;
}
@@ -488,23 +507,15 @@ static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t
return ret;
}
-static ssize_t __vfs_write(struct file *file, const char __user *p,
- size_t count, loff_t *pos)
-{
- if (file->f_op->write)
- return file->f_op->write(file, p, count, pos);
- else if (file->f_op->write_iter)
- return new_sync_write(file, p, count, pos);
- else
- return -EINVAL;
-}
-
+/* caller is responsible for file_start_write/file_end_write */
ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos)
{
mm_segment_t old_fs;
const char __user *p;
ssize_t ret;
+ if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE)))
+ return -EBADF;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;
@@ -513,7 +524,12 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t
p = (__force const char __user *)buf;
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
- ret = __vfs_write(file, p, count, pos);
+ if (file->f_op->write)
+ ret = file->f_op->write(file, p, count, pos);
+ else if (file->f_op->write_iter)
+ ret = new_sync_write(file, p, count, pos);
+ else
+ ret = -EINVAL;
set_fs(old_fs);
if (ret > 0) {
fsnotify_modify(file);
@@ -522,21 +538,20 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t
inc_syscw(current);
return ret;
}
-EXPORT_SYMBOL(__kernel_write);
ssize_t kernel_write(struct file *file, const void *buf, size_t count,
loff_t *pos)
{
- mm_segment_t old_fs;
- ssize_t res;
+ ssize_t ret;
- old_fs = get_fs();
- set_fs(KERNEL_DS);
- /* The cast to a user pointer is valid due to the set_fs() */
- res = vfs_write(file, (__force const char __user *)buf, count, pos);
- set_fs(old_fs);
+ ret = rw_verify_area(WRITE, file, pos, count);
+ if (ret)
+ return ret;
- return res;
+ file_start_write(file);
+ ret = __kernel_write(file, buf, count, pos);
+ file_end_write(file);
+ return ret;
}
EXPORT_SYMBOL(kernel_write);
@@ -552,19 +567,23 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
return -EFAULT;
ret = rw_verify_area(WRITE, file, pos, count);
- if (!ret) {
- if (count > MAX_RW_COUNT)
- count = MAX_RW_COUNT;
- file_start_write(file);
- ret = __vfs_write(file, buf, count, pos);
- if (ret > 0) {
- fsnotify_modify(file);
- add_wchar(current, ret);
- }
- inc_syscw(current);
- file_end_write(file);
+ if (ret)
+ return ret;
+ if (count > MAX_RW_COUNT)
+ count = MAX_RW_COUNT;
+ file_start_write(file);
+ if (file->f_op->write)
+ ret = file->f_op->write(file, buf, count, pos);
+ else if (file->f_op->write_iter)
+ ret = new_sync_write(file, buf, count, pos);
+ else
+ ret = -EINVAL;
+ if (ret > 0) {
+ fsnotify_modify(file);
+ add_wchar(current, ret);
}
-
+ inc_syscw(current);
+ file_end_write(file);
return ret;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4b7cb76e5837..f5abba86107d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1918,7 +1918,6 @@ ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
struct iovec *fast_pointer,
struct iovec **ret_pointer);
-extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *);
extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
@@ -3034,6 +3033,7 @@ extern int kernel_read_file_from_path_initns(const char *, void **, loff_t *, lo
extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
enum kernel_read_file_id);
extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *);
+ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos);
extern ssize_t kernel_write(struct file *, const void *, size_t, loff_t *);
extern ssize_t __kernel_write(struct file *, const void *, size_t, loff_t *);
extern struct file * open_exec(const char *);
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index c0f0990f30b6..1905e01c3aa9 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -50,7 +50,7 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname,
req.len = optlen;
if (!bpfilter_ops.info.pid)
goto out;
- n = __kernel_write(bpfilter_ops.info.pipe_to_umh, &req, sizeof(req),
+ n = kernel_write(bpfilter_ops.info.pipe_to_umh, &req, sizeof(req),
&pos);
if (n != sizeof(req)) {
pr_err("write fail %zd\n", n);
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index e12c4900510f..1d20003243c3 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -188,19 +188,7 @@ DEFINE_LSM(integrity) = {
int integrity_kernel_read(struct file *file, loff_t offset,
void *addr, unsigned long count)
{
- mm_segment_t old_fs;
- char __user *buf = (char __user *)addr;
- ssize_t ret;
-
- if (!(file->f_mode & FMODE_READ))
- return -EBADF;
-
- old_fs = get_fs();
- set_fs(KERNEL_DS);
- ret = __vfs_read(file, buf, count, &offset);
- set_fs(old_fs);
-
- return ret;
+ return __kernel_read(file, addr, count, &offset);
}
/*