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| author | Andrew Donnellan <ajd@linux.ibm.com> | 2020-11-20 02:52:42 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-11-22 12:00:23 +0300 |
| commit | 6f830a304bf5fb768395642e49fb4e9375469e48 (patch) | |
| tree | 3e1ec75f6652fb0bfc2dad4a684cabb3a5f82745 /arch/powerpc/lib | |
| parent | 24ed3d53a4bd16144cb319b3d5f406be15a1e3fa (diff) | |
| download | linux-6f830a304bf5fb768395642e49fb4e9375469e48.tar.xz | |
powerpc: Fix __clear_user() with KUAP enabled
commit 61e3acd8c693a14fc69b824cb5b08d02cb90a6e7 upstream.
The KUAP implementation adds calls in clear_user() to enable and
disable access to userspace memory. However, it doesn't add these to
__clear_user(), which is used in the ptrace regset code.
As there's only one direct user of __clear_user() (the regset code),
and the time taken to set the AMR for KUAP purposes is going to
dominate the cost of a quick access_ok(), there's not much point
having a separate path.
Rename __clear_user() to __arch_clear_user(), and make __clear_user()
just call clear_user().
Reported-by: syzbot+f25ecf4b2982d8c7a640@syzkaller-ppc64.appspotmail.com
Reported-by: Daniel Axtens <dja@axtens.net>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Fixes: de78a9c42a79 ("powerpc: Add a framework for Kernel Userspace Access Protection")
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
[mpe: Use __arch_clear_user() for the asm version like arm64 & nds32]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191209132221.15328-1-ajd@linux.ibm.com
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/lib')
| -rw-r--r-- | arch/powerpc/lib/string.S | 4 | ||||
| -rw-r--r-- | arch/powerpc/lib/string_64.S | 6 |
2 files changed, 5 insertions, 5 deletions
diff --git a/arch/powerpc/lib/string.S b/arch/powerpc/lib/string.S index 0378def28d41..7ef5497f3f97 100644 --- a/arch/powerpc/lib/string.S +++ b/arch/powerpc/lib/string.S @@ -88,7 +88,7 @@ _GLOBAL(memchr) EXPORT_SYMBOL(memchr) #ifdef CONFIG_PPC32 -_GLOBAL(__clear_user) +_GLOBAL(__arch_clear_user) addi r6,r3,-4 li r3,0 li r5,0 @@ -128,5 +128,5 @@ _GLOBAL(__clear_user) EX_TABLE(1b, 91b) EX_TABLE(8b, 92b) -EXPORT_SYMBOL(__clear_user) +EXPORT_SYMBOL(__arch_clear_user) #endif diff --git a/arch/powerpc/lib/string_64.S b/arch/powerpc/lib/string_64.S index 56aac4c22025..ea3798f4f25f 100644 --- a/arch/powerpc/lib/string_64.S +++ b/arch/powerpc/lib/string_64.S @@ -29,7 +29,7 @@ PPC64_CACHES: .section ".text" /** - * __clear_user: - Zero a block of memory in user space, with less checking. + * __arch_clear_user: - Zero a block of memory in user space, with less checking. * @to: Destination address, in user space. * @n: Number of bytes to zero. * @@ -70,7 +70,7 @@ err3; stb r0,0(r3) mr r3,r4 blr -_GLOBAL_TOC(__clear_user) +_GLOBAL_TOC(__arch_clear_user) cmpdi r4,32 neg r6,r3 li r0,0 @@ -193,4 +193,4 @@ err1; dcbz 0,r3 cmpdi r4,32 blt .Lshort_clear b .Lmedium_clear -EXPORT_SYMBOL(__clear_user) +EXPORT_SYMBOL(__arch_clear_user) |