From 90db9dbedd26ce029f3a0f8d2cbd3a142f452408 Mon Sep 17 00:00:00 2001 From: Marco Elver Date: Mon, 27 Feb 2023 10:47:27 +0100 Subject: kasan, powerpc: don't rename memintrinsics if compiler adds prefixes With appropriate compiler support [1], KASAN builds use __asan prefixed meminstrinsics, and KASAN no longer overrides memcpy/memset/memmove. If compiler support is detected (CC_HAS_KASAN_MEMINTRINSIC_PREFIX), define memintrinsics normally (do not prefix '__'). On powerpc, KASAN is the only user of __mem functions, which are used to define instrumented memintrinsics. Alias the normal versions for KASAN to use in its implementation. Link: https://lore.kernel.org/all/20230224085942.1791837-1-elver@google.com/ [1] Link: https://lore.kernel.org/oe-kbuild-all/202302271348.U5lvmo0S-lkp@intel.com/ Link: https://lkml.kernel.org/r/20230227094726.3833247-1-elver@google.com Signed-off-by: Marco Elver Reported-by: kernel test robot Acked-by: Michael Ellerman [powerpc] Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Christophe Leroy Cc: Daniel Axtens Cc: Dmitry Vyukov Cc: Liam R. Howlett Cc: Nicholas Piggin Cc: Vincenzo Frascino Signed-off-by: Andrew Morton --- arch/powerpc/kernel/prom_init_check.sh | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh index 5a319863f289..69623b9045d5 100644 --- a/arch/powerpc/kernel/prom_init_check.sh +++ b/arch/powerpc/kernel/prom_init_check.sh @@ -13,8 +13,13 @@ # If you really need to reference something from prom_init.o add # it to the list below: -grep "^CONFIG_KASAN=y$" ${KCONFIG_CONFIG} >/dev/null -if [ $? -eq 0 ] +has_renamed_memintrinsics() +{ + grep -q "^CONFIG_KASAN=y$" ${KCONFIG_CONFIG} && \ + ! grep -q "^CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX=y" ${KCONFIG_CONFIG} +} + +if has_renamed_memintrinsics then MEM_FUNCS="__memcpy __memset" else -- cgit v1.2.3 From fd7276189450110ed835eb0a334e62d2f1c4e3be Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 26 Mar 2023 16:15:57 -0600 Subject: powerpc: Don't try to copy PPR for task with NULL pt_regs powerpc sets up PF_KTHREAD and PF_IO_WORKER with a NULL pt_regs, which from my (arguably very short) checking is not commonly done for other archs. This is fine, except when PF_IO_WORKER's have been created and the task does something that causes a coredump to be generated. Then we get this crash: Kernel attempted to read user page (160) - exploit attempt? (uid: 1000) BUG: Kernel NULL pointer dereference on read at 0x00000160 Faulting instruction address: 0xc0000000000c3a60 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=32 NUMA pSeries Modules linked in: bochs drm_vram_helper drm_kms_helper xts binfmt_misc ecb ctr syscopyarea sysfillrect cbc sysimgblt drm_ttm_helper aes_generic ttm sg libaes evdev joydev virtio_balloon vmx_crypto gf128mul drm dm_mod fuse loop configfs drm_panel_orientation_quirks ip_tables x_tables autofs4 hid_generic usbhid hid xhci_pci xhci_hcd usbcore usb_common sd_mod CPU: 1 PID: 1982 Comm: ppc-crash Not tainted 6.3.0-rc2+ #88 Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries NIP: c0000000000c3a60 LR: c000000000039944 CTR: c0000000000398e0 REGS: c0000000041833b0 TRAP: 0300 Not tainted (6.3.0-rc2+) MSR: 800000000280b033 CR: 88082828 XER: 200400f8 ... NIP memcpy_power7+0x200/0x7d0 LR ppr_get+0x64/0xb0 Call Trace: ppr_get+0x40/0xb0 (unreliable) __regset_get+0x180/0x1f0 regset_get_alloc+0x64/0x90 elf_core_dump+0xb98/0x1b60 do_coredump+0x1c34/0x24a0 get_signal+0x71c/0x1410 do_notify_resume+0x140/0x6f0 interrupt_exit_user_prepare_main+0x29c/0x320 interrupt_exit_user_prepare+0x6c/0xa0 interrupt_return_srr_user+0x8/0x138 Because ppr_get() is trying to copy from a PF_IO_WORKER with a NULL pt_regs. Check for a valid pt_regs in both ppc_get/ppr_set, and return an error if not set. The actual error value doesn't seem to be important here, so just pick -EINVAL. Fixes: fa439810cc1b ("powerpc/ptrace: Enable support for NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR") Cc: stable@vger.kernel.org # v4.8+ Signed-off-by: Jens Axboe [mpe: Trim oops in change log, add Fixes & Cc stable] Signed-off-by: Michael Ellerman Link: https://msgid.link/d9f63344-fe7c-56ae-b420-4a1a04a2ae4c@kernel.dk --- arch/powerpc/kernel/ptrace/ptrace-view.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/powerpc/kernel') diff --git a/arch/powerpc/kernel/ptrace/ptrace-view.c b/arch/powerpc/kernel/ptrace/ptrace-view.c index 2087a785f05f..5fff0d04b23f 100644 --- a/arch/powerpc/kernel/ptrace/ptrace-view.c +++ b/arch/powerpc/kernel/ptrace/ptrace-view.c @@ -290,6 +290,9 @@ static int gpr_set(struct task_struct *target, const struct user_regset *regset, static int ppr_get(struct task_struct *target, const struct user_regset *regset, struct membuf to) { + if (!target->thread.regs) + return -EINVAL; + return membuf_write(&to, &target->thread.regs->ppr, sizeof(u64)); } @@ -297,6 +300,9 @@ static int ppr_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { + if (!target->thread.regs) + return -EINVAL; + return user_regset_copyin(&pos, &count, &kbuf, &ubuf, &target->thread.regs->ppr, 0, sizeof(u64)); } -- cgit v1.2.3