From: andrey.konovalov@linux.dev To: Marco Elver <elver@google.com>, Alexander Potapenko <glider@google.com>, Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Konovalov <andreyknvl@gmail.com>, Dmitry Vyukov <dvyukov@google.com>, Andrey Ryabinin <ryabinin.a.a@gmail.com>, kasan-dev@googlegroups.com, linux-mm@kvack.org, Vincenzo Frascino <vincenzo.frascino@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com>, linux-arm-kernel@lists.infradead.org, Peter Collingbourne <pcc@google.com>, Evgenii Stepanov <eugenis@google.com>, linux-kernel@vger.kernel.org, Andrey Konovalov <andreyknvl@google.com> Subject: [PATCH mm v3 31/38] kasan, arm64: don't tag executable vmalloc allocations Date: Mon, 13 Dec 2021 22:54:27 +0100 [thread overview] Message-ID: <4a5ec956a2666c1f967c9789534a8ac4d4fe26f9.1639432170.git.andreyknvl@google.com> (raw) In-Reply-To: <cover.1639432170.git.andreyknvl@google.com> From: Andrey Konovalov <andreyknvl@google.com> Besides asking vmalloc memory to be executable via the prot argument of __vmalloc_node_range() (see the previous patch), the kernel can skip that bit and instead mark memory as executable via set_memory_x(). Once tag-based KASAN modes start tagging vmalloc allocations, executing code from such allocations will lead to the PC register getting a tag, which is not tolerated by the kernel. Generic kernel code typically allocates memory via module_alloc() if it intends to mark memory as executable. (On arm64 module_alloc() uses __vmalloc_node_range() without setting the executable bit). Thus, reset pointer tags of pointers returned from module_alloc(). However, on arm64 there's an exception: the eBPF subsystem. Instead of using module_alloc(), it uses vmalloc() (via bpf_jit_alloc_exec()) to allocate its JIT region. Thus, reset pointer tags of pointers returned from bpf_jit_alloc_exec(). Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- Changes v2->v3: - Add this patch. --- arch/arm64/kernel/module.c | 3 ++- arch/arm64/net/bpf_jit_comp.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c index d3a1fa818348..f2d4bb14bfab 100644 --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -63,7 +63,8 @@ void *module_alloc(unsigned long size) return NULL; } - return p; + /* Memory is intended to be executable, reset the pointer tag. */ + return kasan_reset_tag(p); } enum aarch64_reloc_op { diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 07aad85848fa..381a67922c2d 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1147,7 +1147,8 @@ u64 bpf_jit_alloc_exec_limit(void) void *bpf_jit_alloc_exec(unsigned long size) { - return vmalloc(size); + /* Memory is intended to be executable, reset the pointer tag. */ + return kasan_reset_tag(vmalloc(size)); } void bpf_jit_free_exec(void *addr) -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: andrey.konovalov@linux.dev To: Marco Elver <elver@google.com>, Alexander Potapenko <glider@google.com>, Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Konovalov <andreyknvl@gmail.com>, Dmitry Vyukov <dvyukov@google.com>, Andrey Ryabinin <ryabinin.a.a@gmail.com>, kasan-dev@googlegroups.com, linux-mm@kvack.org, Vincenzo Frascino <vincenzo.frascino@arm.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Mark Rutland <mark.rutland@arm.com>, linux-arm-kernel@lists.infradead.org, Peter Collingbourne <pcc@google.com>, Evgenii Stepanov <eugenis@google.com>, linux-kernel@vger.kernel.org, Andrey Konovalov <andreyknvl@google.com> Subject: [PATCH mm v3 31/38] kasan, arm64: don't tag executable vmalloc allocations Date: Mon, 13 Dec 2021 22:54:27 +0100 [thread overview] Message-ID: <4a5ec956a2666c1f967c9789534a8ac4d4fe26f9.1639432170.git.andreyknvl@google.com> (raw) In-Reply-To: <cover.1639432170.git.andreyknvl@google.com> From: Andrey Konovalov <andreyknvl@google.com> Besides asking vmalloc memory to be executable via the prot argument of __vmalloc_node_range() (see the previous patch), the kernel can skip that bit and instead mark memory as executable via set_memory_x(). Once tag-based KASAN modes start tagging vmalloc allocations, executing code from such allocations will lead to the PC register getting a tag, which is not tolerated by the kernel. Generic kernel code typically allocates memory via module_alloc() if it intends to mark memory as executable. (On arm64 module_alloc() uses __vmalloc_node_range() without setting the executable bit). Thus, reset pointer tags of pointers returned from module_alloc(). However, on arm64 there's an exception: the eBPF subsystem. Instead of using module_alloc(), it uses vmalloc() (via bpf_jit_alloc_exec()) to allocate its JIT region. Thus, reset pointer tags of pointers returned from bpf_jit_alloc_exec(). Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- Changes v2->v3: - Add this patch. --- arch/arm64/kernel/module.c | 3 ++- arch/arm64/net/bpf_jit_comp.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c index d3a1fa818348..f2d4bb14bfab 100644 --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -63,7 +63,8 @@ void *module_alloc(unsigned long size) return NULL; } - return p; + /* Memory is intended to be executable, reset the pointer tag. */ + return kasan_reset_tag(p); } enum aarch64_reloc_op { diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 07aad85848fa..381a67922c2d 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1147,7 +1147,8 @@ u64 bpf_jit_alloc_exec_limit(void) void *bpf_jit_alloc_exec(unsigned long size) { - return vmalloc(size); + /* Memory is intended to be executable, reset the pointer tag. */ + return kasan_reset_tag(vmalloc(size)); } void bpf_jit_free_exec(void *addr) -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-12-13 21:55 UTC|newest] Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-12-13 21:51 [PATCH mm v3 00/38] kasan, vmalloc, arm64: add vmalloc tagging support for SW/HW_TAGS andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-13 21:51 ` [PATCH mm v3 01/38] kasan, page_alloc: deduplicate should_skip_kasan_poison andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-13 21:51 ` [PATCH mm v3 02/38] kasan, page_alloc: move tag_clear_highpage out of kernel_init_free_pages andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-13 21:51 ` [PATCH mm v3 03/38] kasan, page_alloc: merge kasan_free_pages into free_pages_prepare andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-13 21:51 ` [PATCH mm v3 04/38] kasan, page_alloc: simplify kasan_poison_pages call site andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-16 12:54 ` Alexander Potapenko 2021-12-16 12:54 ` Alexander Potapenko 2021-12-13 21:51 ` [PATCH mm v3 05/38] kasan, page_alloc: init memory of skipped pages on free andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-13 21:51 ` [PATCH mm v3 06/38] kasan: drop skip_kasan_poison variable in free_pages_prepare andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-13 21:51 ` [PATCH mm v3 07/38] mm: clarify __GFP_ZEROTAGS comment andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-13 21:51 ` [PATCH mm v3 08/38] kasan: only apply __GFP_ZEROTAGS when memory is zeroed andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-13 21:51 ` [PATCH mm v3 09/38] kasan, page_alloc: refactor init checks in post_alloc_hook andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-16 13:32 ` Alexander Potapenko 2021-12-16 13:32 ` Alexander Potapenko 2021-12-13 21:51 ` [PATCH mm v3 10/38] kasan, page_alloc: merge kasan_alloc_pages into post_alloc_hook andrey.konovalov 2021-12-13 21:51 ` andrey.konovalov 2021-12-13 21:53 ` [PATCH mm v3 11/38] kasan, page_alloc: combine tag_clear_highpage calls in post_alloc_hook andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-16 13:04 ` Alexander Potapenko 2021-12-16 13:04 ` Alexander Potapenko 2021-12-13 21:53 ` [PATCH mm v3 12/38] kasan, page_alloc: move SetPageSkipKASanPoison " andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-13 21:53 ` [PATCH mm v3 13/38] kasan, page_alloc: move kernel_init_free_pages " andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-16 11:00 ` Alexander Potapenko 2021-12-16 11:00 ` Alexander Potapenko 2021-12-13 21:53 ` [PATCH mm v3 14/38] kasan, page_alloc: simplify kasan_unpoison_pages call site andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-13 21:53 ` [PATCH mm v3 15/38] kasan: clean up metadata byte definitions andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-16 10:52 ` Alexander Potapenko 2021-12-16 10:52 ` Alexander Potapenko 2021-12-13 21:53 ` [PATCH mm v3 16/38] kasan: define KASAN_VMALLOC_INVALID for SW_TAGS andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-13 21:53 ` [PATCH mm v3 17/38] kasan, x86, arm64, s390: rename functions for modules shadow andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-13 21:53 ` [PATCH mm v3 18/38] kasan, vmalloc: drop outdated VM_KASAN comment andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-16 10:53 ` Alexander Potapenko 2021-12-16 10:53 ` Alexander Potapenko 2021-12-13 21:53 ` [PATCH mm v3 19/38] kasan: reorder vmalloc hooks andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-16 10:55 ` Alexander Potapenko 2021-12-16 10:55 ` Alexander Potapenko 2021-12-13 21:53 ` [PATCH mm v3 20/38] kasan: add wrappers for " andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-13 21:53 ` [PATCH mm v3 21/38] kasan, vmalloc: reset tags in vmalloc functions andrey.konovalov 2021-12-13 21:53 ` andrey.konovalov 2021-12-13 21:54 ` [PATCH mm v3 22/38] kasan, fork: reset pointer tags of vmapped stacks andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-13 21:54 ` [PATCH mm v3 23/38] kasan, arm64: " andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-13 21:59 ` Andrey Konovalov 2021-12-13 21:59 ` Andrey Konovalov 2021-12-14 13:25 ` Catalin Marinas 2021-12-14 13:25 ` Catalin Marinas 2021-12-13 21:54 ` [PATCH mm v3 24/38] kasan, vmalloc: add vmalloc tagging for SW_TAGS andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-13 21:54 ` [PATCH mm v3 25/38] kasan, vmalloc, arm64: mark vmalloc mappings as pgprot_tagged andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-14 17:11 ` Catalin Marinas 2021-12-14 17:11 ` Catalin Marinas 2021-12-14 18:27 ` Andrey Konovalov 2021-12-14 18:27 ` Andrey Konovalov 2021-12-14 19:27 ` Catalin Marinas 2021-12-14 19:27 ` Catalin Marinas 2021-12-20 21:38 ` Andrey Konovalov 2021-12-20 21:38 ` Andrey Konovalov 2021-12-13 21:54 ` [PATCH mm v3 26/38] kasan, vmalloc: don't unpoison VM_ALLOC pages before mapping andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-16 19:07 ` Alexander Potapenko 2021-12-16 19:07 ` Alexander Potapenko 2021-12-20 21:35 ` Andrey Konovalov 2021-12-20 21:35 ` Andrey Konovalov 2021-12-13 21:54 ` [PATCH mm v3 27/38] kasan, page_alloc: allow skipping unpoisoning for HW_TAGS andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-13 21:54 ` [PATCH mm v3 28/38] kasan, page_alloc: allow skipping memory init " andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-14 18:00 ` Marco Elver 2021-12-14 18:00 ` Marco Elver 2021-12-14 18:28 ` Andrey Konovalov 2021-12-14 18:28 ` Andrey Konovalov 2021-12-17 1:50 ` Kuan-Ying Lee 2021-12-17 1:50 ` Kuan-Ying Lee 2021-12-20 21:35 ` Andrey Konovalov 2021-12-20 21:35 ` Andrey Konovalov 2021-12-13 21:54 ` [PATCH mm v3 29/38] kasan, vmalloc: add vmalloc tagging " andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-14 19:55 ` Marco Elver 2021-12-14 19:55 ` Marco Elver 2021-12-14 22:08 ` Andrey Konovalov 2021-12-14 22:08 ` Andrey Konovalov 2021-12-14 21:03 ` Marco Elver 2021-12-14 21:03 ` Marco Elver 2021-12-13 21:54 ` [PATCH mm v3 30/38] kasan, vmalloc: don't tag executable vmalloc allocations andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-14 19:42 ` Andrey Konovalov 2021-12-14 19:42 ` Andrey Konovalov 2021-12-13 21:54 ` andrey.konovalov [this message] 2021-12-13 21:54 ` [PATCH mm v3 31/38] kasan, arm64: " andrey.konovalov 2021-12-13 21:59 ` Andrey Konovalov 2021-12-13 21:59 ` Andrey Konovalov 2021-12-17 13:45 ` Catalin Marinas 2021-12-17 13:45 ` Catalin Marinas 2021-12-13 21:54 ` [PATCH mm v3 32/38] kasan: mark kasan_arg_stacktrace as __initdata andrey.konovalov 2021-12-13 21:54 ` andrey.konovalov 2021-12-13 21:55 ` [PATCH mm v3 33/38] kasan: simplify kasan_init_hw_tags andrey.konovalov 2021-12-13 21:55 ` andrey.konovalov 2021-12-13 21:55 ` [PATCH mm v3 34/38] kasan: add kasan.vmalloc command line flag andrey.konovalov 2021-12-13 21:55 ` andrey.konovalov 2021-12-13 21:55 ` [PATCH mm v3 35/38] kasan: allow enabling KASAN_VMALLOC and SW/HW_TAGS andrey.konovalov 2021-12-13 21:55 ` andrey.konovalov 2021-12-13 21:55 ` [PATCH mm v3 36/38] arm64: select KASAN_VMALLOC for SW/HW_TAGS modes andrey.konovalov 2021-12-13 21:55 ` andrey.konovalov 2021-12-13 21:55 ` [PATCH mm v3 37/38] kasan: documentation updates andrey.konovalov 2021-12-13 21:55 ` andrey.konovalov 2021-12-13 21:55 ` [PATCH mm v3 38/38] kasan: improve vmalloc tests andrey.konovalov 2021-12-13 21:55 ` andrey.konovalov
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