https://github.com/torvalds/linux
Revision d93f9e23744b7bf11a98b2ddb091d129482ae179 authored by Christophe Leroy on 15 September 2021, 14:12:24 UTC, committed by Michael Ellerman on 07 October 2021, 12:34:00 UTC
At interrupt exit, kuap_kernel_restore() calls kuap_unlock() with the
value contained in regs->kuap. However, when regs->kuap contains
0xffffffff it means that KUAP was not unlocked so calling kuap_unlock()
is unrelevant and results in jeopardising the contents of kernel space
segment registers.
So check that regs->kuap doesn't contain KUAP_NONE before calling
kuap_unlock(). In the meantime it also means that if KUAP has not
been correcly locked back at interrupt exit, it must be locked
before continuing. This is done by checking the content of
current->thread.kuap which was returned by kuap_get_and_assert_locked()
Fixes: 16132529cee5 ("powerpc/32s: Rework Kernel Userspace Access Protection")
Reported-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0d0c4d0f050a637052287c09ba521bad960a2790.1631715131.git.christophe.leroy@csgroup.eu
1 parent 5a4b032
Tip revision: d93f9e23744b7bf11a98b2ddb091d129482ae179 authored by Christophe Leroy on 15 September 2021, 14:12:24 UTC
powerpc/32s: Fix kuap_kernel_restore()
powerpc/32s: Fix kuap_kernel_restore()
Tip revision: d93f9e2
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| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | -rw-r--r-- | 16.6 KB |
| .cocciconfig | -rw-r--r-- | 59 bytes |
| .get_maintainer.ignore | -rw-r--r-- | 71 bytes |
| .gitattributes | -rw-r--r-- | 62 bytes |
| .gitignore | -rw-r--r-- | 1.9 KB |
| .mailmap | -rw-r--r-- | 19.8 KB |
| COPYING | -rw-r--r-- | 496 bytes |
| CREDITS | -rw-r--r-- | 98.6 KB |
| Kbuild | -rw-r--r-- | 1.3 KB |
| Kconfig | -rw-r--r-- | 555 bytes |
| MAINTAINERS | -rw-r--r-- | 605.7 KB |
| Makefile | -rw-r--r-- | 64.0 KB |
| README | -rw-r--r-- | 727 bytes |
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