From 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 2 Sep 2026 15:31:14 -0700 Subject: treewide: refresh kmalloc_obj() conversions This is another run of the Coccinelle script for converting kmalloc() family of allocations to kmalloc_obj() via the existing rules in scripts/coccinelle/api/kmalloc_objs.cocci This catches both the set of kmalloc() uses added since the first kmalloc_obj() conversions in v7.0 and adds a large group missed in the first pass due to Coccinelle not interacting well with the cleanup.h scoped_...() family of macros[1]. I worked around this with spatch's "--macro-file" argument to a file with all the scoped_...() macros mapped to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control flow indicator I could find. Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc, riscv, and s390 with no new warnings. Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1] Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2] Signed-off-by: Kees Cook --- lib/vdso/datastore.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+) create mode 100644 lib/vdso/datastore.c (limited to 'lib/vdso/datastore.c') diff --git a/lib/vdso/datastore.c b/lib/vdso/datastore.c new file mode 100644 index 000000000..1426bf4e0 --- /dev/null +++ b/lib/vdso/datastore.c @@ -0,0 +1,129 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include +#include +#include +#include +#include +#include + +static u8 vdso_initdata[VDSO_NR_PAGES * PAGE_SIZE] __aligned(PAGE_SIZE) __initdata = {}; + +#ifdef CONFIG_GENERIC_GETTIMEOFDAY +struct vdso_time_data *vdso_k_time_data __ro_after_init = + (void *)&vdso_initdata[VDSO_TIME_PAGE_OFFSET * PAGE_SIZE]; + +static_assert(sizeof(struct vdso_time_data) <= PAGE_SIZE); +#endif /* CONFIG_GENERIC_GETTIMEOFDAY */ + +#ifdef CONFIG_VDSO_GETRANDOM +struct vdso_rng_data *vdso_k_rng_data __ro_after_init = + (void *)&vdso_initdata[VDSO_RNG_PAGE_OFFSET * PAGE_SIZE]; + +static_assert(sizeof(struct vdso_rng_data) <= PAGE_SIZE); +#endif /* CONFIG_VDSO_GETRANDOM */ + +#ifdef CONFIG_ARCH_HAS_VDSO_ARCH_DATA +struct vdso_arch_data *vdso_k_arch_data __ro_after_init = + (void *)&vdso_initdata[VDSO_ARCH_PAGES_START * PAGE_SIZE]; +#endif /* CONFIG_ARCH_HAS_VDSO_ARCH_DATA */ + +static struct page *vdso_data_pages __ro_after_init; + +void __init vdso_setup_data_pages(void) +{ + unsigned int order = get_order(VDSO_NR_PAGES * PAGE_SIZE); + + /* + * Allocate the data pages dynamically. SPARC does not support mapping + * static pages to be mapped into userspace. + * It is also a requirement for mlockall() support. + * + * Do not use folios. In time namespaces the pages are mapped in a different order + * to userspace, which is not handled by the folio optimizations in finish_fault(). + */ + vdso_data_pages = alloc_pages(GFP_KERNEL, order); + if (!vdso_data_pages) + panic("Unable to allocate VDSO storage pages"); + + /* The pages are mapped one-by-one into userspace and each one needs to be refcounted. */ + split_page(vdso_data_pages, order); + + /* Move the data already written by other subsystems to the new pages */ + memcpy(page_address(vdso_data_pages), vdso_initdata, VDSO_NR_PAGES * PAGE_SIZE); + + if (IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY)) + vdso_k_time_data = page_address(vdso_data_pages + VDSO_TIME_PAGE_OFFSET); + + if (IS_ENABLED(CONFIG_VDSO_GETRANDOM)) + vdso_k_rng_data = page_address(vdso_data_pages + VDSO_RNG_PAGE_OFFSET); + + if (IS_ENABLED(CONFIG_ARCH_HAS_VDSO_ARCH_DATA)) + vdso_k_arch_data = page_address(vdso_data_pages + VDSO_ARCH_PAGES_START); +} + +static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, + struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct page *page, *timens_page; + + if (unlikely(vmf->flags & FAULT_FLAG_REMOTE)) + return VM_FAULT_SIGBUS; + + page = vdso_data_pages + vmf->pgoff; + timens_page = find_timens_vvar_page(vma); + + switch (vmf->pgoff) { + case VDSO_TIME_PAGE_OFFSET: + if (!IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY) || !timens_page) + break; + /* + * Fault in VVAR page too, since it will be accessed + * to get clock data anyway. + */ + unsigned long addr; + vm_fault_t err; + + addr = vmf->address + VDSO_TIMENS_PAGE_OFFSET * PAGE_SIZE; + err = vmf_insert_page(vma, addr, page); + if (unlikely(err & VM_FAULT_ERROR)) + return err; + page = timens_page; + break; + case VDSO_TIMENS_PAGE_OFFSET: + /* + * If a task belongs to a time namespace then a namespace + * specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and + * the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET + * offset. + * See also the comment near timens_setup_vdso_data(). + */ + if (!IS_ENABLED(CONFIG_TIME_NS) || !timens_page) + break; + page = vdso_data_pages + VDSO_TIME_PAGE_OFFSET; + break; + case VDSO_RNG_PAGE_OFFSET: + case VDSO_ARCH_PAGES_START ... VDSO_ARCH_PAGES_END: + break; + default: + return VM_FAULT_SIGBUS; + } + + get_page(page); + vmf->page = page; + return 0; +} + +const struct vm_special_mapping vdso_vvar_mapping = { + .name = "[vvar]", + .fault = vvar_fault, +}; + +struct vm_area_struct *vdso_install_vvar_mapping(struct mm_struct *mm, unsigned long addr) +{ + return _install_special_mapping(mm, addr, VDSO_NR_PAGES * PAGE_SIZE, + VM_READ | VM_MAYREAD | VM_DONTDUMP | + VM_MIXEDMAP | VM_SEALED_SYSMAP, + &vdso_vvar_mapping); +} -- cgit v1.3.1