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net/9p: use memcpy() instead of snprintf() in p9_mount_tag_show()

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p9_mount_tag_show() uses '%s' format string to print
non-NULL terminated chan->tag string. This leads
to out of bounds memory read, because format '%s'
implies that string is NULL-terminated.

The length of string is know here, so its simpler and safer
to use memcpy instead of snprintf().

Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
This commit is contained in:
Andrey Ryabinin 2015-01-27 16:00:19 +03:00 committed by Eric Van Hensbergen
parent 6250a8badb
commit 179a5bc4b8
1 changed files with 4 additions and 1 deletions
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5
net/9p/trans_virtio.c
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@ -504,7 +504,10 @@ static ssize_t p9_mount_tag_show(struct device *dev,
vdev = dev_to_virtio(dev);
chan = vdev->priv;
return snprintf(buf, chan->tag_len + 1, "%s", chan->tag);
memcpy(buf, chan->tag, chan->tag_len);
buf[chan->tag_len] = 0;
return chan->tag_len + 1;
}
static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);