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05ccd4cbff
[ Upstream commit 4a6998aff82a20a1aece86a186d8e5263f8b2315 ]
Wenwen Wang reported:
In btf_parse(), the header of the user-space btf data 'btf_data'
is firstly parsed and verified through btf_parse_hdr().
In btf_parse_hdr(), the header is copied from user-space 'btf_data'
to kernel-space 'btf->hdr' and then verified. If no error happens
during the verification process, the whole data of 'btf_data',
including the header, is then copied to 'data' in btf_parse(). It
is obvious that the header is copied twice here. More importantly,
no check is enforced after the second copy to make sure the headers
obtained in these two copies are same. Given that 'btf_data' resides
in the user space, a malicious user can race to modify the header
between these two copies. By doing so, the user can inject
inconsistent data, which can cause undefined behavior of the
kernel and introduce potential security risk.
This issue is similar to the one fixed in commit 8af03d1ae2e1 ("bpf:
btf: Fix a missing check bug"). To fix it, this patch copies the user
'btf_data' *before* parsing / verifying the BTF header.
Fixes: 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Co-developed-by: Wenwen Wang <wang6495@umn.edu>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Cyber Knight <cyberknight755@gmail.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.