This sockopt accepts two kinds of parameters, using struct sctp_sack_info and struct sctp_assoc_value. The mentioned commit didn't notice an implicit cast from the smaller (latter) struct to the bigger one (former) when copying the data from the user space, which now leads to an attempt to write beyond the buffer (because it assumes the storing buffer is bigger than the parameter itself). Fix it by allocating a sctp_sack_info on stack and filling it out based on the small struct for the compat case. Changelog stole from an earlier patch from Marcelo Ricardo Leitner. Fixes: ebb25defdc17 ("sctp: pass a kernel pointer to sctp_setsockopt_delayed_ack") Reported-by: syzbot+0e4699d000d8b874d8dc@syzkaller.appspotmail.com Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.
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