commit f4dce1ffd2e30fa31756876ef502ce6d2324be35 upstream.
Since commit 4c21b8fd8f ("MIPS: seccomp: Handle indirect system calls
(o32)"), syscall_get_arguments() attempts to handle o32 indirect syscall
arguments by incrementing both the start argument number and the number
of arguments to fetch. However only the start argument number needs to
be incremented. The number of arguments does not change, they're just
shifted up by one, and in fact the output array is provided by the
caller and is likely only n entries long, so reading more arguments
overflows the output buffer.
In the case of seccomp, this results in it fetching 7 arguments starting
at the 2nd one, which overflows the unsigned long args[6] in
populate_seccomp_data(). This clobbers the $s0 register from
syscall_trace_enter() which __seccomp_phase1_filter() saved onto the
stack, into which syscall_trace_enter() had placed its syscall number
argument. This caused Chromium to crash.
Credit goes to Milko for tracking it down as far as $s0 being clobbered.
Fixes: 4c21b8fd8f ("MIPS: seccomp: Handle indirect system calls (o32)")
Reported-by: Milko Leporis <milko.leporis@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12213/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When EVA is in use, __copy_from_user() was unconditionally using the EVA
instructions to read the user address space, however this can also be
used for kernel access. If the address isn't a valid user address it
will cause an address error or TLB exception, and if it is then user
memory may be read instead of kernel memory.
For example in the following stack trace from Linux v3.10 (changes since
then will prevent this particular one still happening) kernel_sendmsg()
set the user address limit to KERNEL_DS, and tcp_sendmsg() goes on to
use __copy_from_user() with a kernel address in KSeg0.
[<8002d434>] __copy_fromuser_common+0x10c/0x254
[<805710e0>] tcp_sendmsg+0x5f4/0xf00
[<804e8e3c>] sock_sendmsg+0x78/0xa0
[<804e8f28>] kernel_sendmsg+0x24/0x38
[<804ee0f8>] sock_no_sendpage+0x70/0x7c
[<8017c820>] pipe_to_sendpage+0x80/0x98
[<8017c6b0>] splice_from_pipe_feed+0xa8/0x198
[<8017cc54>] __splice_from_pipe+0x4c/0x8c
[<8017e844>] splice_from_pipe+0x58/0x78
[<8017e884>] generic_splice_sendpage+0x20/0x2c
[<8017d690>] do_splice_from+0xb4/0x110
[<8017d710>] direct_splice_actor+0x24/0x30
[<8017d394>] splice_direct_to_actor+0xd8/0x208
[<8017d51c>] do_splice_direct+0x58/0x7c
[<8014eaf4>] do_sendfile+0x1dc/0x39c
[<8014f82c>] SyS_sendfile+0x90/0xf8
Add the eva_kernel_access() check in __copy_from_user() like the one in
copy_from_user().
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10843/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The strlen_user() function calls __strlen_kernel_asm in both branches of
the eva_kernel_access() conditional. For EVA it should be calling
__strlen_user_eva for user accesses, otherwise it will load from the
kernel address space instead of the user address space, and the access
checking will likely be ineffective at preventing it due to EVA's
overlapping user and kernel address spaces.
This was found after extending the test_user_copy module to cover user
string access functions, which gave the following error with EVA:
test_user_copy: illegal strlen_user passed
Fortunately the use of strlen_user() has been all but eradicated from
the mainline kernel, so only out of tree modules could be affected.
Fixes: e3a9b07a9c ("MIPS: asm: uaccess: Add EVA support for str*_user operations")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.15.x-
Patchwork: https://patchwork.linux-mips.org/patch/10842/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
./arch/mips/include/asm/page.h:204:13: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
The default value of ARCH_PFN_OFFSET is 0 thus triggering this warning
for all platforms using the default value.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull MIPS updates from Ralf Baechle:
"These are the highlists of the main MIPS pull request for 4.4:
- Add latencytop support
- Support appended DTBs
- VDSO support and initially use it for gettimeofday.
- Drop the .MIPS.abiflags and ELF NOTE sections from vmlinux
- Support for the 5KE, an internal test core.
- Switch all MIPS platfroms to libata drivers.
- Improved support, cleanups for ralink and Lantiq platforms.
- Support for the new xilfpga platform.
- A number of DTB improvments for BMIPS.
- Improved support for CM and CPS.
- Minor JZ4740 and BCM47xx enhancements"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (120 commits)
MIPS: idle: add case for CPU_5KE
MIPS: Octeon: Support APPENDED_DTB
MIPS: vmlinux: create a section for appended DTB
MIPS: Clean up compat_siginfo_t
MIPS: Fix PAGE_MASK definition
MIPS: BMIPS: Enable GZIP ramdisk and timed printks
MIPS: Add xilfpga defconfig
MIPS: xilfpga: Add mipsfpga platform code
MIPS: xilfpga: Add xilfpga device tree files.
dt-bindings: MIPS: Document xilfpga bindings and boot style
MIPS: Make MIPS_CMDLINE_DTB default
MIPS: Make the kernel arguments from dtb available
MIPS: Use USE_OF as the guard for appended dtb
MIPS: BCM63XX: Use pr_* instead of printk
MIPS: Loongson: Cleanup CONFIG_LOONGSON_SUSPEND.
MIPS: lantiq: Disable xbar fpi burst mode
MIPS: lantiq: Force the crossbar to big endian
MIPS: lantiq: Initialize the USB core on boot
MIPS: lantiq: Return correct value for fpi clock on ar9
MIPS: ralink: Add missing clock on rt305x
...
While mips can't use the generic compat_siginfo_t directly because
its si_code and si_errno are inverted, we can still make it as
close to the generic version as possible. This makes it easier
to update when new members are added to siginfo_t.
The main changes are adding a missing _sigsys union member and
eliminating the unused _irix_sigchld one.
Signed-off-by: Amanieu d'Antras <amanieu@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11455/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add user-mode implementations of gettimeofday() and clock_gettime() to
the VDSO. This is currently usable with 2 clocksources: the CP0 count
register, which is accessible to user-mode via RDHWR on R2 and later
cores, or the MIPS Global Interrupt Controller (GIC) timer, which
provides a "user-mode visible" section containing a mirror of its
counter registers. This section must be mapped into user memory, which
is done below the VDSO data page.
When a supported clocksource is not in use, the VDSO functions will
return -ENOSYS, which causes libc to fall back on the standard syscall
path.
When support for neither of these clocksources is compiled into the
kernel at all, the VDSO still provides clock_gettime(), as the coarse
realtime/monotonic clocks can still be implemented. However,
gettimeofday() is not provided in this case as nothing can be done
without a suitable clocksource. This causes the symbol lookup to fail
in libc and it will then always use the standard syscall path.
This patch includes a workaround for a bug in QEMU which results in
RDHWR on the CP0 count register always returning a constant (incorrect)
value. A fix for this has been submitted, and the workaround can be
removed after the fix has been in stable releases for a reasonable
amount of time.
A simple performance test which calls gettimeofday() 1000 times in a
loop and calculates the average execution time gives the following
results on a Malta + I6400 (running at 20MHz):
- Syscall: ~31000 ns
- VDSO (GIC): ~15000 ns
- VDSO (CP0): ~9500 ns
[markos.chandras@imgtec.com:
- Minor code re-arrangements in order for mappings to be made
in the order they appear to the process' address space.
- Move do_{monotonic, realtime} outside of the MIPS_CLOCK_VSYSCALL ifdef
- Use gic_get_usm_range so we can do the GIC mapping in the
arch/mips/kernel/vdso instead of the GIC irqchip driver]
Signed-off-by: Alex Smith <alex.smith@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11338/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add an initial implementation of a proper (i.e. an ELF shared library)
VDSO. With this commit it does not export any symbols, it only replaces
the current signal return trampoline page. A later commit will add user
implementations of gettimeofday()/clock_gettime().
To support both new toolchains and old ones which don't generate ABI
flags section, we define its content manually and then use a tool
(genvdso) to patch up the section to have the correct name and type.
genvdso also extracts symbol offsets ({,rt_}sigreturn) needed by the
kernel, and generates a C file containing a "struct mips_vdso_image"
containing both the VDSO data and these offsets. This C file is
compiled into the kernel.
On 64-bit kernels we require a different VDSO for each supported ABI,
so we may build up to 3 different VDSOs. The VDSO to use is selected by
the mips_abi structure.
A kernel/user shared data page is created and mapped below the VDSO
image. This is currently empty, but will be used by the user time
function implementations which are added later.
[markos.chandras@imgtec.com:
- Add more comments
- Move abi detection in genvdso.h since it's the get_symbol function
that needs it.
- Add an R6 specific way to calculate the base address of VDSO in order
to avoid the branch instruction which affects performance.
- Do not patch .gnu.attributes since it's not needed for dynamic linking.
- Simplify Makefile a little bit.
- checkpatch fixes
- Restrict VDSO support for binutils < 2.25 for pre-R6
- Include atomic64.h for O32 variant on MIPS64]
Signed-off-by: Alex Smith <alex.smith@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11337/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Commit a68d09a156 ("MIPS: Don't use RI/XI with 32-bit kernels on
64-bit CPUs") prevented use of RIXI on MIPS64 systems, stating that the
"TLB handlers cannot handle this case". What they actually couldn't
handle was cases where there were less fill bits in the Entry{Lo,Hi}
registers than bits used by software in PTEs. The handlers can now deal
with this case, so enable RIXI for MIPS32 kernels on MIPS64 systems.
Note that beyond the obvious benefits provided by having RIXI on such
systems, this is required for systems implementing MIPSr6 where RIXI
cannot be disabled.
This reverts commit a68d09a156 ("MIPS: Don't use RI/XI with 32-bit
kernels on 64-bit CPUs").
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/11219/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
