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authorAl Viro <viro@zeniv.linux.org.uk>2016-03-31 21:48:20 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2016-04-03 19:51:39 -0400
commitbc61384dcdd82a6faabafecdcd80040625db5e40 (patch)
treeac9b46ce9b1d9e24e8158bc9577f061e3aaaaf3a /fs/read_write.c
parent2958ec177e400be1e26fc37e1759f84fa2c1761c (diff)
downloadlinux-bc61384dcdd82a6faabafecdcd80040625db5e40.tar.bz2
rw_verify_area(): saner calling conventions
Lift length capping into the few callers that care about it. Most of them treat all non-negatives as "success" and ignore the capped value, and with good reasons. Make rw_verify_area() return 0 on success. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c33
1 files changed, 14 insertions, 19 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index cf377cf9dfe3..b1a0e6ca218f 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -410,11 +410,6 @@ ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
}
EXPORT_SYMBOL(vfs_iter_write);
-/*
- * rw_verify_area doesn't like huge counts. We limit
- * them to something that fits in "int" so that others
- * won't have to do range checks all the time.
- */
int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
{
struct inode *inode;
@@ -441,11 +436,8 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t
if (retval < 0)
return retval;
}
- retval = security_file_permission(file,
+ return security_file_permission(file,
read_write == READ ? MAY_READ : MAY_WRITE);
- if (retval)
- return retval;
- return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
}
static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
@@ -489,8 +481,9 @@ 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 >= 0) {
- count = ret;
+ if (!ret) {
+ if (count > MAX_RW_COUNT)
+ count = MAX_RW_COUNT;
ret = __vfs_read(file, buf, count, pos);
if (ret > 0) {
fsnotify_access(file);
@@ -572,8 +565,9 @@ 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 >= 0) {
- count = ret;
+ 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) {
@@ -1323,7 +1317,8 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
retval = rw_verify_area(READ, in.file, &pos, count);
if (retval < 0)
goto fput_in;
- count = retval;
+ if (count > MAX_RW_COUNT)
+ count = MAX_RW_COUNT;
/*
* Get output file, and verify that it is ok..
@@ -1341,7 +1336,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
retval = rw_verify_area(WRITE, out.file, &out_pos, count);
if (retval < 0)
goto fput_out;
- count = retval;
if (!max)
max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
@@ -1485,11 +1479,12 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
if (flags != 0)
return -EINVAL;
- /* copy_file_range allows full ssize_t len, ignoring MAX_RW_COUNT */
ret = rw_verify_area(READ, file_in, &pos_in, len);
- if (ret >= 0)
- ret = rw_verify_area(WRITE, file_out, &pos_out, len);
- if (ret < 0)
+ if (unlikely(ret))
+ return ret;
+
+ ret = rw_verify_area(WRITE, file_out, &pos_out, len);
+ if (unlikely(ret))
return ret;
if (!(file_in->f_mode & FMODE_READ) ||