Minimal supplement to upstream Kernel Self Protection Project changes. Features already provided by SELinux + Yama and archs other than multiarch arm64 / x86_64 aren't in scope. Only tags have stable history. Shared IRC channel with KSPP: irc.libera.chat #linux-hardening
b2a2ab527d
The bounds checks in known_siginfo_layout only guards against positive
numbers that are too large, large negative can slip through and
can cause out of bounds accesses.
Ordinarily this is not a concern because early in signal processing
the signal number is filtered with valid_signal which ensures it
is a small positive signal number, but copy_siginfo_from_user
is called before this check is performed.
[ 73.031126] BUG: unable to handle kernel paging request at ffffffff6281bcb6
[ 73.032038] PGD 3014067 P4D 3014067 PUD 0
[ 73.032565] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[ 73.033287] CPU: 0 PID: 732 Comm: trinity-c3 Tainted: G W T 4.19.0-rc1-00077-g4ce5f9c #1
[ 73.034423] RIP: 0010:copy_siginfo_from_user+0x4d/0xd0
[ 73.034908] Code: 00 8b 53 08 81 fa 80 00 00 00 0f 84 90 00 00 00 85 d2 7e 2d 48 63 0b 83 f9 1f 7f 1c 8d 71 ff bf d8 04 01 50 48 0f a3 f7 73 0e <0f> b6 8c 09 20 bb 81 82 39 ca 7f 15 eb 68 31 c0 83 fa 06 7f 0c eb
[ 73.036665] RSP: 0018:ffff88001b8f7e20 EFLAGS: 00010297
[ 73.037160] RAX: 0000000000000000 RBX: ffff88001b8f7e90 RCX: fffffffff00000cb
[ 73.037865] RDX: 0000000000000001 RSI: 00000000f00000ca RDI: 00000000500104d8
[ 73.038546] RBP: ffff88001b8f7e80 R08: 0000000000000000 R09: 0000000000000000
[ 73.039201] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000008
[ 73.039874] R13: 00000000000002dc R14: 0000000000000000 R15: 0000000000000000
[ 73.040613] FS: 000000000104a880(0000) GS:ffff88001f000000(0000) knlGS:0000000000000000
[ 73.041649] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 73.042405] CR2: ffffffff6281bcb6 CR3: 000000001cb52003 CR4: 00000000001606b0
[ 73.043351] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 73.044286] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
[ 73.045221] Call Trace:
[ 73.045556] __x64_sys_rt_tgsigqueueinfo+0x34/0xa0
[ 73.046199] do_syscall_64+0x1a4/0x390
[ 73.046708] ? vtime_user_enter+0x61/0x80
[ 73.047242] ? __context_tracking_enter+0x4e/0x60
[ 73.047714] ? __context_tracking_enter+0x4e/0x60
[ 73.048278] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Therefore fix known_siginfo_layout to take an unsigned signal number
instead of a signed signal number. All valid signal numbers are small
positive numbers so they will not be affected, but invalid negative
signal numbers will now become large positive signal numbers and will
not be used as indices into the sig_sicodes array.
Making the signal number unsigned makes it difficult for similar mistakes to
happen in the future.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.
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.