bc1b4f013b
The check for max offset in sk_msg_is_valid_access uses sizeof()
which is incorrect because it would allow accessing possibly
past the end of the struct in the padded case. Further, it doesn't
preclude accessing any padding that may be added in the middle of
a struct. All told this makes it fragile to rely on.
To fix this explicitly check offsets with fields using the
bpf_ctx_range() and bpf_ctx_range_till() macros.
For reference the current structure layout looks as follows (reported
by pahole)
struct sk_msg_md {
union {
void * data; /* 8 */
}; /* 0 8 */
union {
void * data_end; /* 8 */
}; /* 8 8 */
__u32 family; /* 16 4 */
__u32 remote_ip4; /* 20 4 */
__u32 local_ip4; /* 24 4 */
__u32 remote_ip6[4]; /* 28 16 */
__u32 local_ip6[4]; /* 44 16 */
__u32 remote_port; /* 60 4 */
/* --- cacheline 1 boundary (64 bytes) --- */
__u32 local_port; /* 64 4 */
__u32 size; /* 68 4 */
/* size: 72, cachelines: 2, members: 10 */
/* last cacheline: 8 bytes */
};
So there should be no padding at the moment but fixing this now
prevents future errors.
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.