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A mirror of the official Linux kernel repository just in case
ca2d49f77c
splice_to_socket() assumes that a pipe_buffer won't hold more than a single
page of data - but this assumption can be violated by skb_splice_bits()
when it splices from a socket into a pipe.
The problem is that splice_to_socket() doesn't advance the pipe_buffer
length and offset when transcribing from the pipe buf into a bio_vec, so if
the buf is >PAGE_SIZE, it keeps repeating the same initial chunk and
doesn't advance the tail index. It then subtracts this from "remain" and
overcounts the amount of data to be sent.
The cleanup phase then tries to overclean the pipe, hits an unused pipe buf
and a NULL-pointer dereference occurs.
Fix this by not restricting the bio_vec size to PAGE_SIZE and instead
transcribing the entirety of each pipe_buffer into a single bio_vec and
advancing the tail index if remain hasn't hit zero yet.
Large bio_vecs will then be split up by iterator functions such as
iov_iter_extract_pages().
This resulted in a KASAN report looking like:
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
...
RIP: 0010:pipe_buf_release include/linux/pipe_fs_i.h:203 [inline]
RIP: 0010:splice_to_socket+0xa91/0xe30 fs/splice.c:933
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.