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authorTomas Winkler <tomas.winkler@intel.com>2013-09-02 03:11:04 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-09-26 08:23:01 -0700
commitdd5de1f165ade430357960459491a067c7e3d21c (patch)
tree456a28f27a8945b1025325cc2cf76a59b257c616 /drivers/misc
parente19555ce893f7567c7a72f91dafe6bdb93f0198f (diff)
mei: revamp read and write length checks
1. Return zero on zero length read and writes 2. For a too large write return -EFBIG as defined in man write(2) EFBIG An attempt was made to write a file that exceeds the implementation-defined maximum file size or the process's file size limit, or to write at a position past the maximum allowed offset. Signed-off-by: Tomas Winkler <tomas.winkler@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/mei/main.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index 5ff810b1e8b..7404584e65e 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -203,12 +203,18 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
dev = cl->dev;
+
mutex_lock(&dev->device_lock);
if (dev->dev_state != MEI_DEV_ENABLED) {
rets = -ENODEV;
goto out;
}
+ if (length == 0) {
+ rets = 0;
+ goto out;
+ }
+
if (cl == &dev->iamthif_cl) {
rets = mei_amthif_read(dev, file, ubuf, length, offset);
goto out;
@@ -350,8 +356,14 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
rets = -ENODEV;
goto out;
}
- if (length > dev->me_clients[id].props.max_msg_length || length <= 0) {
- rets = -EMSGSIZE;
+
+ if (length == 0) {
+ rets = 0;
+ goto out;
+ }
+
+ if (length > dev->me_clients[id].props.max_msg_length) {
+ rets = -EFBIG;
goto out;
}