3.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ming Lei <[email protected]> commit e5110f411d2ee35bf8d202ccca2e89c633060dca upstream. In case of 'if (filp->f_pos == 0 or 1)' of sysfs_readdir(), the failure from filldir() isn't handled, and the reference counter of the sysfs_dirent object pointed by filp->private_data will be released without clearing filp->private_data, so use after free bug will be triggered later. This patch returns immeadiately under the situation for fixing the bug, and it is reasonable to return from readdir() when filldir() fails. Reported-by: Dave Jones <[email protected]> Tested-by: Sasha Levin <[email protected]> Signed-off-by: Ming Lei <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/sysfs/dir.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -1002,6 +1002,8 @@ static int sysfs_readdir(struct file * f ino = parent_sd->s_ino; if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0) filp->f_pos++; + else + return 0; } if (filp->f_pos == 1) { if (parent_sd->s_parent) @@ -1010,6 +1012,8 @@ static int sysfs_readdir(struct file * f ino = parent_sd->s_ino; if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0) filp->f_pos++; + else + return 0; } mutex_lock(&sysfs_mutex); for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
