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Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c103
1 files changed, 63 insertions, 40 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 9c0485236e68..431a0ed610c8 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -31,6 +31,20 @@ const struct file_operations generic_ro_fops = {
EXPORT_SYMBOL(generic_ro_fops);
+static int
+__negative_fpos_check(struct file *file, loff_t pos, size_t count)
+{
+ /*
+ * pos or pos+count is negative here, check overflow.
+ * too big "count" will be caught in rw_verify_area().
+ */
+ if ((pos < 0) && (pos + count < pos))
+ return -EOVERFLOW;
+ if (file->f_mode & FMODE_UNSIGNED_OFFSET)
+ return 0;
+ return -EINVAL;
+}
+
/**
* generic_file_llseek_unlocked - lockless generic llseek implementation
* @file: file structure to seek on
@@ -62,7 +76,9 @@ generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)
break;
}
- if (offset < 0 || offset > inode->i_sb->s_maxbytes)
+ if (offset < 0 && __negative_fpos_check(file, offset, 0))
+ return -EINVAL;
+ if (offset > inode->i_sb->s_maxbytes)
return -EINVAL;
/* Special lock needed here? */
@@ -124,7 +140,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
{
loff_t retval;
- lock_kernel();
+ mutex_lock(&file->f_dentry->d_inode->i_mutex);
switch (origin) {
case SEEK_END:
offset += i_size_read(file->f_path.dentry->d_inode);
@@ -137,7 +153,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
offset += file->f_pos;
}
retval = -EINVAL;
- if (offset >= 0) {
+ if (offset >= 0 || !__negative_fpos_check(file, offset, 0)) {
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
@@ -145,7 +161,7 @@ loff_t default_llseek(struct file *file, loff_t offset, int origin)
retval = offset;
}
out:
- unlock_kernel();
+ mutex_unlock(&file->f_dentry->d_inode->i_mutex);
return retval;
}
EXPORT_SYMBOL(default_llseek);
@@ -156,7 +172,6 @@ loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
fn = no_llseek;
if (file->f_mode & FMODE_LSEEK) {
- fn = default_llseek;
if (file->f_op && file->f_op->llseek)
fn = file->f_op->llseek;
}
@@ -222,13 +237,12 @@ bad:
}
#endif
+
/*
* 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.
*/
-#define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)
-
int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count)
{
struct inode *inode;
@@ -239,8 +253,11 @@ int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count
if (unlikely((ssize_t) count < 0))
return retval;
pos = *ppos;
- if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
- return retval;
+ if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) {
+ retval = __negative_fpos_check(file, pos, count);
+ if (retval)
+ return retval;
+ }
if (unlikely(inode->i_flock && mandatory_lock(inode))) {
retval = locks_mandatory_area(
@@ -311,7 +328,7 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
else
ret = do_sync_read(file, buf, count, pos);
if (ret > 0) {
- fsnotify_access(file->f_path.dentry);
+ fsnotify_access(file);
add_rchar(current, ret);
}
inc_syscr(current);
@@ -367,7 +384,7 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
else
ret = do_sync_write(file, buf, count, pos);
if (ret > 0) {
- fsnotify_modify(file->f_path.dentry);
+ fsnotify_modify(file);
add_wchar(current, ret);
}
inc_syscw(current);
@@ -565,65 +582,71 @@ ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
unsigned long nr_segs, unsigned long fast_segs,
struct iovec *fast_pointer,
struct iovec **ret_pointer)
- {
+{
unsigned long seg;
- ssize_t ret;
+ ssize_t ret;
struct iovec *iov = fast_pointer;
- /*
- * SuS says "The readv() function *may* fail if the iovcnt argument
- * was less than or equal to 0, or greater than {IOV_MAX}. Linux has
- * traditionally returned zero for zero segments, so...
- */
+ /*
+ * SuS says "The readv() function *may* fail if the iovcnt argument
+ * was less than or equal to 0, or greater than {IOV_MAX}. Linux has
+ * traditionally returned zero for zero segments, so...
+ */
if (nr_segs == 0) {
ret = 0;
- goto out;
+ goto out;
}
- /*
- * First get the "struct iovec" from user memory and
- * verify all the pointers
- */
+ /*
+ * First get the "struct iovec" from user memory and
+ * verify all the pointers
+ */
if (nr_segs > UIO_MAXIOV) {
ret = -EINVAL;
- goto out;
+ goto out;
}
if (nr_segs > fast_segs) {
- iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
+ iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
if (iov == NULL) {
ret = -ENOMEM;
- goto out;
+ goto out;
}
- }
+ }
if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
ret = -EFAULT;
- goto out;
+ goto out;
}
- /*
+ /*
* According to the Single Unix Specification we should return EINVAL
* if an element length is < 0 when cast to ssize_t or if the
* total length would overflow the ssize_t return value of the
* system call.
- */
+ *
+ * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the
+ * overflow case.
+ */
ret = 0;
- for (seg = 0; seg < nr_segs; seg++) {
- void __user *buf = iov[seg].iov_base;
- ssize_t len = (ssize_t)iov[seg].iov_len;
+ for (seg = 0; seg < nr_segs; seg++) {
+ void __user *buf = iov[seg].iov_base;
+ ssize_t len = (ssize_t)iov[seg].iov_len;
/* see if we we're about to use an invalid len or if
* it's about to overflow ssize_t */
- if (len < 0 || (ret + len < ret)) {
+ if (len < 0) {
ret = -EINVAL;
- goto out;
+ goto out;
}
if (unlikely(!access_ok(vrfy_dir(type), buf, len))) {
ret = -EFAULT;
- goto out;
+ goto out;
+ }
+ if (len > MAX_RW_COUNT - ret) {
+ len = MAX_RW_COUNT - ret;
+ iov[seg].iov_len = len;
}
-
ret += len;
- }
+ }
out:
*ret_pointer = iov;
return ret;
@@ -675,9 +698,9 @@ out:
kfree(iov);
if ((ret + (type == READ)) > 0) {
if (type == READ)
- fsnotify_access(file->f_path.dentry);
+ fsnotify_access(file);
else
- fsnotify_modify(file->f_path.dentry);
+ fsnotify_modify(file);
}
return ret;
}
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-06-03 16:13:26 +0200