14f46c1e51
When ieee80211_skb_resize() is called from ieee80211_build_hdr() the skb has no 802.11 header yet, in fact it consist only of the payload as the ethernet frame is removed. As such, we're using the payload data for ieee80211_is_mgmt(), which is of course completely wrong. This didn't really hurt us because these are always data frames, so we could only have added more tailroom than we needed if we determined it was a management frame and sdata->crypto_tx_tailroom_needed_cnt was false. However, syzbot found that of course there need not be any payload, so we're using at best uninitialized memory for the check. Fix this to pass explicitly the kind of frame that we have instead of checking there, by replacing the "bool may_encrypt" argument with an argument that can carry the three possible states - it's not going to be encrypted, it's a management frame, or it's a data frame (and then we check sdata->crypto_tx_tailroom_needed_cnt). Reported-by: syzbot+32fd1a1bfe355e93f1e2@syzkaller.appspotmail.com Signed-off-by: Johannes Berg <johannes.berg@intel.com> Link: https://lore.kernel.org/r/20201009132538.e1fd7f802947.I799b288466ea2815f9d4c84349fae697dca2f189@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.