[21/74] sysfs: fix race between readdir and lseek
3.2.43-rc1 review patch. If anyone has any objections, please let me know.
--
From: Ming Lei
commit 991f76f837bf22c5bb07261cfd86525a0a96650c upstream.
While readdir() is running, lseek() may set filp->f_pos as zero,
then may leave filp->private_data pointing to one sysfs_dirent
object without holding its reference counter, so the sysfs_dirent
object may be used after free in next readdir().
This patch holds inode->i_mutex to avoid the problem since
the lock is always held in readdir path.
Reported-by: Dave Jones
Tested-by: Sasha Levin
Signed-off-by: Ming Lei
Signed-off-by: Greg Kroah-Hartman
[bwh: Backported to 3.2: open-code file_inode() which we don't have]
Signed-off-by: Ben Hutchings
---
fs/sysfs/dir.c | 13 -
1 file changed, 12 insertions(+), 1 deletion(-)
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -1023,10 +1023,21 @@ static int sysfs_readdir(struct file * f
return 0;
}
+static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ loff_t ret;
+
+ mutex_lock(>i_mutex);
+ ret = generic_file_llseek(file, offset, whence);
+ mutex_unlock(>i_mutex);
+
+ return ret;
+}
const struct file_operations sysfs_dir_operations = {
.read = generic_read_dir,
.readdir= sysfs_readdir,
.release= sysfs_dir_release,
- .llseek = generic_file_llseek,
+ .llseek = sysfs_dir_llseek,
};
--
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[21/74] sysfs: fix race between readdir and lseek
3.2.43-rc1 review patch. If anyone has any objections, please let me know.
--
From: Ming Lei ming@canonical.com
commit 991f76f837bf22c5bb07261cfd86525a0a96650c upstream.
While readdir() is running, lseek() may set filp-f_pos as zero,
then may leave filp-private_data pointing to one sysfs_dirent
object without holding its reference counter, so the sysfs_dirent
object may be used after free in next readdir().
This patch holds inode-i_mutex to avoid the problem since
the lock is always held in readdir path.
Reported-by: Dave Jones da...@redhat.com
Tested-by: Sasha Levin levinsasha...@gmail.com
Signed-off-by: Ming Lei ming@canonical.com
Signed-off-by: Greg Kroah-Hartman gre...@linuxfoundation.org
[bwh: Backported to 3.2: open-code file_inode() which we don't have]
Signed-off-by: Ben Hutchings b...@decadent.org.uk
---
fs/sysfs/dir.c | 13 -
1 file changed, 12 insertions(+), 1 deletion(-)
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -1023,10 +1023,21 @@ static int sysfs_readdir(struct file * f
return 0;
}
+static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct inode *inode = file-f_path.dentry-d_inode;
+ loff_t ret;
+
+ mutex_lock(inode-i_mutex);
+ ret = generic_file_llseek(file, offset, whence);
+ mutex_unlock(inode-i_mutex);
+
+ return ret;
+}
const struct file_operations sysfs_dir_operations = {
.read = generic_read_dir,
.readdir= sysfs_readdir,
.release= sysfs_dir_release,
- .llseek = generic_file_llseek,
+ .llseek = sysfs_dir_llseek,
};
--
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