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ec1aae190c
Fix boot crash on Raspberry Pi by moving the update to `event->datalen` before data is copied into flexible-array member `data` via `memcpy()`. Flexible-array member `data` was annotated with `__counted_by(datalen)` in commit62d19b3580("wifi: brcmfmac: fweh: Add __counted_by for struct brcmf_fweh_queue_item and use struct_size()"). The intention of this is to gain visibility into the size of `data` at run-time through its _counter_ (in this case `datalen`), and with this have its accesses bounds-checked at run-time via CONFIG_FORTIFY_SOURCE and CONFIG_UBSAN_BOUNDS. To effectively accomplish the above, we shall update the counter (`datalen`), before the first access to the flexible array (`data`), which was also done in the mentioned commit. However, commitedec428219("wifi: brcmfmac: allow per-vendor event handling") inadvertently caused a buffer overflow, detected by FORTIFY_SOURCE. It moved the `event->datalen = datalen;` update to after the first `data` access, at which point `event->datalen` was not yet updated from zero (after calling `kzalloc()`), leading to the overflow issue. This fix repositions the `event->datalen = datalen;` update before accessing `data`, restoring the intended buffer overflow protection. :) Fixes:edec428219("wifi: brcmfmac: allow per-vendor event handling") Reported-by: Nathan Chancellor <nathan@kernel.org> Closes: https://gist.github.com/nathanchance/e22f681f3bfc467f15cdf6605021aaa6 Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com> Signed-off-by: Kalle Valo <kvalo@kernel.org> Link: https://msgid.link/Zc+3PFCUvLoVlpg8@neat
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.