From 3052636aa9aa2492ccac973449be63cae5b93a67 Mon Sep 17 00:00:00 2001 From: Zheng Yongjun Date: Wed, 16 Dec 2020 21:11:59 +0800 Subject: x86/mtrr: Convert comma to semicolon Replace a comma between expression statements with a semicolon. Signed-off-by: Zheng Yongjun Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20201216131159.14393-1-zhengyongjun3@huawei.com --- arch/x86/kernel/cpu/mtrr/cleanup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c index 5bd011737272..9231640782fa 100644 --- a/arch/x86/kernel/cpu/mtrr/cleanup.c +++ b/arch/x86/kernel/cpu/mtrr/cleanup.c @@ -537,9 +537,9 @@ static void __init print_out_mtrr_range_state(void) if (!size_base) continue; - size_base = to_size_factor(size_base, &size_factor), + size_base = to_size_factor(size_base, &size_factor); start_base = range_state[i].base_pfn << (PAGE_SHIFT - 10); - start_base = to_size_factor(start_base, &start_factor), + start_base = to_size_factor(start_base, &start_factor); type = range_state[i].type; pr_debug("reg %d, base: %ld%cB, range: %ld%cB, type %s\n", -- cgit From 91a8f6cb06b33adc79fbf5f7381d907485767c00 Mon Sep 17 00:00:00 2001 From: Adrian Huang Date: Thu, 17 Dec 2020 13:26:48 +0800 Subject: x86/mm: Refine mmap syscall implementation It is unnecessary to use the local variable 'error' in the mmap syscall implementation function - just return -EINVAL directly and get rid of the local variable altogether. [ bp: Massage commit message. ] Signed-off-by: Adrian Huang Signed-off-by: Borislav Petkov Reviewed-by: Christoph Hellwig Link: https://lkml.kernel.org/r/20201217052648.24656-1-adrianhuang0701@gmail.com --- arch/x86/kernel/sys_x86_64.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index 504fa5425bce..660b78827638 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -90,14 +90,10 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, unsigned long, prot, unsigned long, flags, unsigned long, fd, unsigned long, off) { - long error; - error = -EINVAL; if (off & ~PAGE_MASK) - goto out; + return -EINVAL; - error = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT); -out: - return error; + return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT); } static void find_start_end(unsigned long addr, unsigned long flags, -- cgit From b86cb29287be07041b81f5611e37ae9ffabff876 Mon Sep 17 00:00:00 2001 From: Tom Rix Date: Thu, 14 Jan 2021 13:28:27 -0800 Subject: x86: Remove definition of DEBUG Defining DEBUG should only be done in development. So remove it. Signed-off-by: Tom Rix Signed-off-by: Borislav Petkov Acked-by: Steven Rostedt (VMware) Link: https://lkml.kernel.org/r/20210114212827.47584-1-trix@redhat.com --- arch/x86/kernel/cpu/mtrr/generic.c | 1 - arch/x86/kernel/cpu/mtrr/mtrr.c | 2 -- arch/x86/kernel/pci-iommu_table.c | 3 --- 3 files changed, 6 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index 23ad8e953dfb..2cf4465d5693 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -3,7 +3,6 @@ * This only handles 32bit MTRR on 32bit hosts. This is strictly wrong * because MTRRs can span up to 40 bits (36bits on most modern x86) */ -#define DEBUG #include #include diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c index 61eb26edc6d2..28c8a23aa42e 100644 --- a/arch/x86/kernel/cpu/mtrr/mtrr.c +++ b/arch/x86/kernel/cpu/mtrr/mtrr.c @@ -31,8 +31,6 @@ System Programming Guide; Section 9.11. (1997 edition - PPro). */ -#define DEBUG - #include /* FIXME: kvm_para.h needs this */ #include diff --git a/arch/x86/kernel/pci-iommu_table.c b/arch/x86/kernel/pci-iommu_table.c index 2e9006c1e240..42e92ec62973 100644 --- a/arch/x86/kernel/pci-iommu_table.c +++ b/arch/x86/kernel/pci-iommu_table.c @@ -4,9 +4,6 @@ #include #include - -#define DEBUG 1 - static struct iommu_table_entry * __init find_dependents_of(struct iommu_table_entry *start, struct iommu_table_entry *finish, -- cgit From 8ece53ef7f428ee3f8eab936268b1a3fe2725e6b Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Tue, 19 Jan 2021 09:40:55 -0800 Subject: x86/vm86/32: Remove VM86_SCREEN_BITMAP support The implementation was rather buggy. It unconditionally marked PTEs read-only, even for VM_SHARED mappings. I'm not sure whether this is actually a problem, but it certainly seems unwise. More importantly, it released the mmap lock before flushing the TLB, which could allow a racing CoW operation to falsely believe that the underlying memory was not writable. I can't find any users at all of this mechanism, so just remove it. Signed-off-by: Andy Lutomirski Signed-off-by: Borislav Petkov Acked-by: Stas Sergeev Link: https://lkml.kernel.org/r/f3086de0babcab36f69949b5780bde851f719bc8.1611078018.git.luto@kernel.org --- arch/x86/kernel/vm86_32.c | 62 +++++++++++------------------------------------ 1 file changed, 14 insertions(+), 48 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c index 764573de3996..e5a7a10a0164 100644 --- a/arch/x86/kernel/vm86_32.c +++ b/arch/x86/kernel/vm86_32.c @@ -134,7 +134,11 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval) unsafe_put_user(regs->ds, &user->regs.ds, Efault_end); unsafe_put_user(regs->fs, &user->regs.fs, Efault_end); unsafe_put_user(regs->gs, &user->regs.gs, Efault_end); - unsafe_put_user(vm86->screen_bitmap, &user->screen_bitmap, Efault_end); + + /* + * Don't write screen_bitmap in case some user had a value there + * and expected it to remain unchanged. + */ user_access_end(); @@ -160,49 +164,6 @@ Efault: do_exit(SIGSEGV); } -static void mark_screen_rdonly(struct mm_struct *mm) -{ - struct vm_area_struct *vma; - spinlock_t *ptl; - pgd_t *pgd; - p4d_t *p4d; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - int i; - - mmap_write_lock(mm); - pgd = pgd_offset(mm, 0xA0000); - if (pgd_none_or_clear_bad(pgd)) - goto out; - p4d = p4d_offset(pgd, 0xA0000); - if (p4d_none_or_clear_bad(p4d)) - goto out; - pud = pud_offset(p4d, 0xA0000); - if (pud_none_or_clear_bad(pud)) - goto out; - pmd = pmd_offset(pud, 0xA0000); - - if (pmd_trans_huge(*pmd)) { - vma = find_vma(mm, 0xA0000); - split_huge_pmd(vma, pmd, 0xA0000); - } - if (pmd_none_or_clear_bad(pmd)) - goto out; - pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); - for (i = 0; i < 32; i++) { - if (pte_present(*pte)) - set_pte(pte, pte_wrprotect(*pte)); - pte++; - } - pte_unmap_unlock(pte, ptl); -out: - mmap_write_unlock(mm); - flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, PAGE_SHIFT, false); -} - - - static int do_vm86_irq_handling(int subfunction, int irqnumber); static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus); @@ -282,6 +243,15 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus) offsetof(struct vm86_struct, int_revectored))) return -EFAULT; + + /* VM86_SCREEN_BITMAP had numerous bugs and appears to have no users. */ + if (v.flags & VM86_SCREEN_BITMAP) { + char comm[TASK_COMM_LEN]; + + pr_info_once("vm86: '%s' uses VM86_SCREEN_BITMAP, which is no longer supported\n", get_task_comm(comm, current)); + return -EINVAL; + } + memset(&vm86regs, 0, sizeof(vm86regs)); vm86regs.pt.bx = v.regs.ebx; @@ -302,7 +272,6 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus) vm86regs.gs = v.regs.gs; vm86->flags = v.flags; - vm86->screen_bitmap = v.screen_bitmap; vm86->cpu_type = v.cpu_type; if (copy_from_user(&vm86->int_revectored, @@ -370,9 +339,6 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus) update_task_stack(tsk); preempt_enable(); - if (vm86->flags & VM86_SCREEN_BITMAP) - mark_screen_rdonly(tsk->mm); - memcpy((struct kernel_vm86_regs *)regs, &vm86regs, sizeof(vm86regs)); return regs->ax; } -- cgit From f22fecaf39c30acce701ffc3e9875020ba31f1f5 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 3 Feb 2021 10:09:58 -0800 Subject: x86/ptrace: Clean up PTRACE_GETREGS/PTRACE_PUTREGS regset selection MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit task_user_regset_view() has nonsensical semantics, but those semantics appear to be relied on by existing users of PTRACE_GETREGSET and PTRACE_SETREGSET. (See added comments below for details.) It shouldn't be used for PTRACE_GETREGS or PTRACE_SETREGS, though. A native 64-bit ptrace() call and an x32 ptrace() call using GETREGS or SETREGS wants the 64-bit regset views, and a 32-bit ptrace() call (native or compat) should use the 32-bit regset. task_user_regset_view() almost does this except that it will malfunction if a ptracer is itself ptraced and the outer ptracer modifies CS on entry to a ptrace() syscall. Hopefully that has never happened. (The compat ptrace() code already hardcoded the 32-bit regset, so this change has no effect on that path.) Improve the situation and deobfuscate the code by hardcoding the 64-bit view in the x32 ptrace() and selecting the view based on the kernel config in the native ptrace(). I tried to figure out the history behind this API. I naïvely assumed that PTRAGE_GETREGSET and PTRACE_SETREGSET were ancient APIs that predated compat, but no. They were introduced by 2225a122ae26 ("ptrace: Add support for generic PTRACE_GETREGSET/PTRACE_SETREGSET") in 2010, and they are simply a poor design. ELF core dumps have the ELF e_machine field and a bunch of register sets in ELF notes, and the pair (e_machine, NT_XXX) indicates the format of the regset blob. But the new PTRACE_GET/SETREGSET API coopted the NT_XXX numbering without any way to specify which e_machine was in effect. This is especially bad on x86, where a process can freely switch between 32-bit and 64-bit mode, and, in fact, the PTRAGE_SETREGSET call itself can cause this switch to happen. Oops. Signed-off-by: Andy Lutomirski Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/9daa791d0c7eaebd59c5bc2b2af1b0e7bebe707d.1612375698.git.luto@kernel.org --- arch/x86/kernel/ptrace.c | 46 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 38 insertions(+), 8 deletions(-) (limited to 'arch/x86/kernel') diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index bedca011459c..87a4143aa7d7 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -704,6 +704,9 @@ void ptrace_disable(struct task_struct *child) #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION static const struct user_regset_view user_x86_32_view; /* Initialized below. */ #endif +#ifdef CONFIG_X86_64 +static const struct user_regset_view user_x86_64_view; /* Initialized below. */ +#endif long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data) @@ -711,6 +714,14 @@ long arch_ptrace(struct task_struct *child, long request, int ret; unsigned long __user *datap = (unsigned long __user *)data; +#ifdef CONFIG_X86_64 + /* This is native 64-bit ptrace() */ + const struct user_regset_view *regset_view = &user_x86_64_view; +#else + /* This is native 32-bit ptrace() */ + const struct user_regset_view *regset_view = &user_x86_32_view; +#endif + switch (request) { /* read the word at location addr in the USER area. */ case PTRACE_PEEKUSR: { @@ -749,28 +760,28 @@ long arch_ptrace(struct task_struct *child, long request, case PTRACE_GETREGS: /* Get all gp regs from the child. */ return copy_regset_to_user(child, - task_user_regset_view(current), + regset_view, REGSET_GENERAL, 0, sizeof(struct user_regs_struct), datap); case PTRACE_SETREGS: /* Set all gp regs in the child. */ return copy_regset_from_user(child, - task_user_regset_view(current), + regset_view, REGSET_GENERAL, 0, sizeof(struct user_regs_struct), datap); case PTRACE_GETFPREGS: /* Get the child FPU state. */ return copy_regset_to_user(child, - task_user_regset_view(current), + regset_view, REGSET_FP, 0, sizeof(struct user_i387_struct), datap); case PTRACE_SETFPREGS: /* Set the child FPU state. */ return copy_regset_from_user(child, - task_user_regset_view(current), + regset_view, REGSET_FP, 0, sizeof(struct user_i387_struct), datap); @@ -1152,28 +1163,28 @@ static long x32_arch_ptrace(struct task_struct *child, case PTRACE_GETREGS: /* Get all gp regs from the child. */ return copy_regset_to_user(child, - task_user_regset_view(current), + &user_x86_64_view, REGSET_GENERAL, 0, sizeof(struct user_regs_struct), datap); case PTRACE_SETREGS: /* Set all gp regs in the child. */ return copy_regset_from_user(child, - task_user_regset_view(current), + &user_x86_64_view, REGSET_GENERAL, 0, sizeof(struct user_regs_struct), datap); case PTRACE_GETFPREGS: /* Get the child FPU state. */ return copy_regset_to_user(child, - task_user_regset_view(current), + &user_x86_64_view, REGSET_FP, 0, sizeof(struct user_i387_struct), datap); case PTRACE_SETFPREGS: /* Set the child FPU state. */ return copy_regset_from_user(child, - task_user_regset_view(current), + &user_x86_64_view, REGSET_FP, 0, sizeof(struct user_i387_struct), datap); @@ -1309,6 +1320,25 @@ void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask) xstate_fx_sw_bytes[USER_XSTATE_XCR0_WORD] = xstate_mask; } +/* + * This is used by the core dump code to decide which regset to dump. The + * core dump code writes out the resulting .e_machine and the corresponding + * regsets. This is suboptimal if the task is messing around with its CS.L + * field, but at worst the core dump will end up missing some information. + * + * Unfortunately, it is also used by the broken PTRACE_GETREGSET and + * PTRACE_SETREGSET APIs. These APIs look at the .regsets field but have + * no way to make sure that the e_machine they use matches the caller's + * expectations. The result is that the data format returned by + * PTRACE_GETREGSET depends on the returned CS field (and even the offset + * of the returned CS field depends on its value!) and the data format + * accepted by PTRACE_SETREGSET is determined by the old CS value. The + * upshot is that it is basically impossible to use these APIs correctly. + * + * The best way to fix it in the long run would probably be to add new + * improved ptrace() APIs to read and write registers reliably, possibly by + * allowing userspace to select the ELF e_machine variant that they expect. + */ const struct user_regset_view *task_user_regset_view(struct task_struct *task) { #ifdef CONFIG_IA32_EMULATION -- cgit