From patchwork Wed Jul 3 18:31:10 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 809469 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2EA5018F2F6; Wed, 3 Jul 2024 18:31:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031494; cv=none; b=Znul9YsaGNnEz9ZUMuKG6/pYV30vM1HZlnwh/6hB6SI8ltCaMX/ExV3ieYaRrLmV+9L10tYlvUHibNziCsooe5AAF64HnwLGXyRPEAnoRlUaqT/9Ls7Fuo8N3S1EBSHxJ0N/AcldXg9gd4DZIxa36Mq1hl1ZmnbGQW1I50YRB0w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031494; c=relaxed/simple; bh=1Fpcy4ervknPwQxb/YDArXHc3RHBD5XelXB4z6hmiQI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BfrlFNEeEgG+aEeghstHy1XvcjHzct9LKbbasRtT5rX4HIwdJytL+l3rLvOp9vqJeGFCdbEYNpttvrc58sXitPY4UXf6vS+KZP5AODihDXQSjwnk5tQOa5QvrlVFYfjh2W8wx3GfZ3f8ehZFDbDH1mvR27QDBgoLDehnBbXI3GY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=olZfhcJB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="olZfhcJB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC01EC4AF0C; Wed, 3 Jul 2024 18:31:32 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="olZfhcJB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1720031492; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=d0Pby7OxE/1C+lYdUs8thNDbc8OeW5PLCiKIriM529Y=; b=olZfhcJBtdERpEzYierYBXSZcHY9wW3m4JgKW8osiVG1AtnVWrzjpmmfQjWLR/l3PO2gER AnSmT31iGX7v3oRkau/HpTo/Qjpf7que5DvirgjpRGybm+jP8V2OQLE+Lx2kIowK8T/Lyw QBKBbw3t+v195NYDmXiZ2K2gDY+2EoI= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 5b4494b4 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Wed, 3 Jul 2024 18:31:32 +0000 (UTC) From: "Jason A. Donenfeld" To: linux-kernel@vger.kernel.org, patches@lists.linux.dev, tglx@linutronix.de Cc: "Jason A. Donenfeld" , linux-crypto@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, Greg Kroah-Hartman , Adhemerval Zanella Netto , Carlos O'Donell , Florian Weimer , Arnd Bergmann , Jann Horn , Christian Brauner , David Hildenbrand , linux-mm@kvack.org Subject: [PATCH v20 1/5] mm: add VM_DROPPABLE for designating always lazily freeable mappings Date: Wed, 3 Jul 2024 20:31:10 +0200 Message-ID: <20240703183115.1075219-2-Jason@zx2c4.com> In-Reply-To: <20240703183115.1075219-1-Jason@zx2c4.com> References: <20240703183115.1075219-1-Jason@zx2c4.com> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The vDSO getrandom() implementation works with a buffer allocated with a new system call that has certain requirements: - It shouldn't be written to core dumps. * Easy: VM_DONTDUMP. - It should be zeroed on fork. * Easy: VM_WIPEONFORK. - It shouldn't be written to swap. * Uh-oh: mlock is rlimited. * Uh-oh: mlock isn't inherited by forks. It turns out that the vDSO getrandom() function has three really nice characteristics that we can exploit to solve this problem: 1) Due to being wiped during fork(), the vDSO code is already robust to having the contents of the pages it reads zeroed out midway through the function's execution. 2) In the absolute worst case of whatever contingency we're coding for, we have the option to fallback to the getrandom() syscall, and everything is fine. 3) The buffers the function uses are only ever useful for a maximum of 60 seconds -- a sort of cache, rather than a long term allocation. These characteristics mean that we can introduce VM_DROPPABLE, which has the following semantics: a) It never is written out to swap. b) Under memory pressure, mm can just drop the pages (so that they're zero when read back again). c) It is inherited by fork. d) It doesn't count against the mlock budget, since nothing is locked. This is fairly simple to implement, with the one snag that we have to use 64-bit VM_* flags, but this shouldn't be a problem, since the only consumers will probably be 64-bit anyway. This way, allocations used by vDSO getrandom() can use: VM_DROPPABLE | VM_DONTDUMP | VM_WIPEONFORK | VM_NORESERVE And there will be no problem with using memory when not in use, not wiping on fork(), coredumps, or writing out to swap. When this functionality is exposed via vgetrandom_alloc() later in this series, a userspace selftest is added that verifies this is working as intended. Cc: linux-mm@kvack.org Signed-off-by: Jason A. Donenfeld --- fs/proc/task_mmu.c | 3 +++ include/linux/mm.h | 8 ++++++++ include/trace/events/mmflags.h | 7 +++++++ mm/Kconfig | 3 +++ mm/mprotect.c | 2 +- mm/rmap.c | 16 +++++++++++++--- 6 files changed, 35 insertions(+), 4 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 71e5039d940d..b3bd8432f869 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -709,6 +709,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) #endif #ifdef CONFIG_64BIT [ilog2(VM_SEALED)] = "sl", +#endif +#ifdef CONFIG_NEED_VM_DROPPABLE + [ilog2(VM_DROPPABLE)] = "dp", #endif }; size_t i; diff --git a/include/linux/mm.h b/include/linux/mm.h index eb7c96d24ac0..92454a0272ce 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -321,12 +321,14 @@ extern unsigned int kobjsize(const void *objp); #define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_5 37 /* bit only usable on 64-bit architectures */ +#define VM_HIGH_ARCH_BIT_6 38 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0) #define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1) #define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2) #define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3) #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) #define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5) +#define VM_HIGH_ARCH_6 BIT(VM_HIGH_ARCH_BIT_6) #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ #ifdef CONFIG_ARCH_HAS_PKEYS @@ -357,6 +359,12 @@ extern unsigned int kobjsize(const void *objp); # define VM_SHADOW_STACK VM_NONE #endif +#ifdef CONFIG_NEED_VM_DROPPABLE +# define VM_DROPPABLE VM_HIGH_ARCH_6 +#else +# define VM_DROPPABLE VM_NONE +#endif + #if defined(CONFIG_X86) # define VM_PAT VM_ARCH_1 /* PAT reserves whole VMA at once (x86) */ #elif defined(CONFIG_PPC) diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index e46d6e82765e..fab7848df50a 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -165,6 +165,12 @@ IF_HAVE_PG_ARCH_X(arch_3) # define IF_HAVE_UFFD_MINOR(flag, name) #endif +#ifdef CONFIG_NEED_VM_DROPPABLE +# define IF_HAVE_VM_DROPPABLE(flag, name) {flag, name}, +#else +# define IF_HAVE_VM_DROPPABLE(flag, name) +#endif + #define __def_vmaflag_names \ {VM_READ, "read" }, \ {VM_WRITE, "write" }, \ @@ -197,6 +203,7 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty" ) \ {VM_MIXEDMAP, "mixedmap" }, \ {VM_HUGEPAGE, "hugepage" }, \ {VM_NOHUGEPAGE, "nohugepage" }, \ +IF_HAVE_VM_DROPPABLE(VM_DROPPABLE, "droppable" ) \ {VM_MERGEABLE, "mergeable" } \ #define show_vma_flags(flags) \ diff --git a/mm/Kconfig b/mm/Kconfig index b4cb45255a54..6cd65ea4b3ad 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1056,6 +1056,9 @@ config ARCH_USES_HIGH_VMA_FLAGS bool config ARCH_HAS_PKEYS bool +config NEED_VM_DROPPABLE + select ARCH_USES_HIGH_VMA_FLAGS + bool config ARCH_USES_PG_ARCH_X bool diff --git a/mm/mprotect.c b/mm/mprotect.c index 8c6cd8825273..57b8dad9adcc 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -623,7 +623,7 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb, may_expand_vm(mm, oldflags, nrpages)) return -ENOMEM; if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_HUGETLB| - VM_SHARED|VM_NORESERVE))) { + VM_SHARED|VM_NORESERVE|VM_DROPPABLE))) { charged = nrpages; if (security_vm_enough_memory_mm(mm, charged)) return -ENOMEM; diff --git a/mm/rmap.c b/mm/rmap.c index e8fc5ecb59b2..56d7535d5cf6 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1397,7 +1397,10 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma, VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio); VM_BUG_ON_VMA(address < vma->vm_start || address + (nr << PAGE_SHIFT) > vma->vm_end, vma); - __folio_set_swapbacked(folio); + /* VM_DROPPABLE mappings don't swap; instead they're just dropped when + * under memory pressure. */ + if (!(vma->vm_flags & VM_DROPPABLE)) + __folio_set_swapbacked(folio); __folio_set_anon(folio, vma, address, true); if (likely(!folio_test_large(folio))) { @@ -1841,7 +1844,11 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, * plus the rmap(s) (dropped by discard:). */ if (ref_count == 1 + map_count && - !folio_test_dirty(folio)) { + (!folio_test_dirty(folio) || + /* Unlike MADV_FREE mappings, VM_DROPPABLE + * ones can be dropped even if they've + * been dirtied. */ + (vma->vm_flags & VM_DROPPABLE))) { dec_mm_counter(mm, MM_ANONPAGES); goto discard; } @@ -1851,7 +1858,10 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, * discarded. Remap the page to page table. */ set_pte_at(mm, address, pvmw.pte, pteval); - folio_set_swapbacked(folio); + /* Unlike MADV_FREE mappings, VM_DROPPABLE ones + * never get swap backed on failure to drop. */ + if (!(vma->vm_flags & VM_DROPPABLE)) + folio_set_swapbacked(folio); ret = false; page_vma_mapped_walk_done(&pvmw); break; From patchwork Wed Jul 3 18:31:12 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 809468 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 55ED6187543; Wed, 3 Jul 2024 18:31:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031513; cv=none; b=ZlLIsPRH4WDLRLyB+3fkb71tuxEGPDY/ZhuMrcpSpmq3oTAWMsGmKHij5dbn0RQ82BRdyfl+k+sIS/SAS62ROffr0yZkaaX6dC8eRhkFW7ApSe09o0pXW/MCque/x68F+O8crf0t0jQ3oPgnBbFoRm3parWNmwn7kFj1Usmt65I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031513; c=relaxed/simple; bh=mlKrlZsM2kxxH+2KQS5wVbypnk5Nt1Pj/gYe5SLqVyc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nB4/b+WLg9hBC3Ppmvz5R8Ak236U+R53uoPG0LwsPFuJMtbLimzllnlPzLk9OFzbjZlXJHFjYrq7GaYi/gZaQdei6tLrh30NlZW+teFV8eVVoaprcAk8Et84D2BQGPlcOid7Dx+zj1NpE91774yweegiozLq3TZpmDYT33FrjS0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=l2KVI/Q1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="l2KVI/Q1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A276CC32781; Wed, 3 Jul 2024 18:31:51 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="l2KVI/Q1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1720031510; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oTGFstFNiRrivg7s+0hzqneNA0GxmnYcJcWIVfMpi9Q=; b=l2KVI/Q1PfUrSRtHhsE7tPhNKAjeLKQgSySG8N5E/9FDRzwhUWCstSy1ua3aBaceHarLSG CtN955DzrLjxjsusgWBspKRLwos0LAcwTdnZztYJLKc1vIkL15MQK72sFzlljYXItZ0DZI qPPdFvLSjW5f+wEdH7O3Nw2sV+WV3ak= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 6853b275 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Wed, 3 Jul 2024 18:31:49 +0000 (UTC) From: "Jason A. Donenfeld" To: linux-kernel@vger.kernel.org, patches@lists.linux.dev, tglx@linutronix.de Cc: "Jason A. Donenfeld" , linux-crypto@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, Greg Kroah-Hartman , Adhemerval Zanella Netto , Carlos O'Donell , Florian Weimer , Arnd Bergmann , Jann Horn , Christian Brauner , David Hildenbrand , Geert Uytterhoeven Subject: [PATCH v20 3/5] arch: allocate vgetrandom_alloc() syscall number Date: Wed, 3 Jul 2024 20:31:12 +0200 Message-ID: <20240703183115.1075219-4-Jason@zx2c4.com> In-Reply-To: <20240703183115.1075219-1-Jason@zx2c4.com> References: <20240703183115.1075219-1-Jason@zx2c4.com> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add vgetrandom_alloc() as syscall 463 (or 573 on alpha) by adding it to all of the various syscall.tbl and unistd.h files. Acked-by: Geert Uytterhoeven Signed-off-by: Jason A. Donenfeld --- arch/alpha/kernel/syscalls/syscall.tbl | 1 + arch/arm/tools/syscall.tbl | 1 + arch/arm64/include/asm/unistd.h | 2 +- arch/arm64/include/asm/unistd32.h | 2 ++ arch/m68k/kernel/syscalls/syscall.tbl | 1 + arch/microblaze/kernel/syscalls/syscall.tbl | 1 + arch/mips/kernel/syscalls/syscall_n32.tbl | 1 + arch/mips/kernel/syscalls/syscall_n64.tbl | 1 + arch/mips/kernel/syscalls/syscall_o32.tbl | 1 + arch/parisc/kernel/syscalls/syscall.tbl | 1 + arch/powerpc/kernel/syscalls/syscall.tbl | 1 + arch/s390/kernel/syscalls/syscall.tbl | 1 + arch/sh/kernel/syscalls/syscall.tbl | 1 + arch/sparc/kernel/syscalls/syscall.tbl | 1 + arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + arch/xtensa/kernel/syscalls/syscall.tbl | 1 + include/uapi/asm-generic/unistd.h | 5 ++++- tools/include/uapi/asm-generic/unistd.h | 5 ++++- tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl | 1 + tools/perf/arch/powerpc/entry/syscalls/syscall.tbl | 1 + tools/perf/arch/s390/entry/syscalls/syscall.tbl | 1 + tools/perf/arch/x86/entry/syscalls/syscall_64.tbl | 1 + 23 files changed, 30 insertions(+), 3 deletions(-) diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl index 74720667fe09..8c38193bf86a 100644 --- a/arch/alpha/kernel/syscalls/syscall.tbl +++ b/arch/alpha/kernel/syscalls/syscall.tbl @@ -502,3 +502,4 @@ 570 common lsm_set_self_attr sys_lsm_set_self_attr 571 common lsm_list_modules sys_lsm_list_modules 572 common mseal sys_mseal +573 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl index 2ed7d229c8f9..118e41178905 100644 --- a/arch/arm/tools/syscall.tbl +++ b/arch/arm/tools/syscall.tbl @@ -476,3 +476,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h index 1346579f802f..6067f617273f 100644 --- a/arch/arm64/include/asm/unistd.h +++ b/arch/arm64/include/asm/unistd.h @@ -39,7 +39,7 @@ #define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE + 5) #define __ARM_NR_COMPAT_END (__ARM_NR_COMPAT_BASE + 0x800) -#define __NR_compat_syscalls 463 +#define __NR_compat_syscalls 464 #endif #define __ARCH_WANT_SYS_CLONE diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h index 1386e8e751f2..f7a45c1788b3 100644 --- a/arch/arm64/include/asm/unistd32.h +++ b/arch/arm64/include/asm/unistd32.h @@ -931,6 +931,8 @@ __SYSCALL(__NR_lsm_set_self_attr, sys_lsm_set_self_attr) __SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules) #define __NR_mseal 462 __SYSCALL(__NR_mseal, sys_mseal) +#define __NR_vgetrandom_alloc 463 +__SYSCALL(__NR_vgetrandom_alloc, sys_vgetrandom_alloc) /* * Please add new compat syscalls above this comment and update diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl index 22a3cbd4c602..bd919d1a8231 100644 --- a/arch/m68k/kernel/syscalls/syscall.tbl +++ b/arch/m68k/kernel/syscalls/syscall.tbl @@ -462,3 +462,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl index 2b81a6bd78b2..d3d3c017a5bb 100644 --- a/arch/microblaze/kernel/syscalls/syscall.tbl +++ b/arch/microblaze/kernel/syscalls/syscall.tbl @@ -468,3 +468,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl index 953f5b7dc723..502cedc0f84d 100644 --- a/arch/mips/kernel/syscalls/syscall_n32.tbl +++ b/arch/mips/kernel/syscalls/syscall_n32.tbl @@ -401,3 +401,4 @@ 460 n32 lsm_set_self_attr sys_lsm_set_self_attr 461 n32 lsm_list_modules sys_lsm_list_modules 462 n32 mseal sys_mseal +463 n32 vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl index 1464c6be6eb3..33710f855c46 100644 --- a/arch/mips/kernel/syscalls/syscall_n64.tbl +++ b/arch/mips/kernel/syscalls/syscall_n64.tbl @@ -377,3 +377,4 @@ 460 n64 lsm_set_self_attr sys_lsm_set_self_attr 461 n64 lsm_list_modules sys_lsm_list_modules 462 n64 mseal sys_mseal +463 n64 vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl index 2439a2491cff..f342d3f26396 100644 --- a/arch/mips/kernel/syscalls/syscall_o32.tbl +++ b/arch/mips/kernel/syscalls/syscall_o32.tbl @@ -450,3 +450,4 @@ 460 o32 lsm_set_self_attr sys_lsm_set_self_attr 461 o32 lsm_list_modules sys_lsm_list_modules 462 o32 mseal sys_mseal +463 o32 vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl index 66dc406b12e4..cddae8bc6fd5 100644 --- a/arch/parisc/kernel/syscalls/syscall.tbl +++ b/arch/parisc/kernel/syscalls/syscall.tbl @@ -461,3 +461,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl index ebae8415dfbb..5c01ec49f510 100644 --- a/arch/powerpc/kernel/syscalls/syscall.tbl +++ b/arch/powerpc/kernel/syscalls/syscall.tbl @@ -553,3 +553,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl index 01071182763e..f5abf7e496ee 100644 --- a/arch/s390/kernel/syscalls/syscall.tbl +++ b/arch/s390/kernel/syscalls/syscall.tbl @@ -465,3 +465,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl index c55fd7696d40..b911231478ee 100644 --- a/arch/sh/kernel/syscalls/syscall.tbl +++ b/arch/sh/kernel/syscalls/syscall.tbl @@ -466,3 +466,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl index cfdfb3707c16..7578d0dee5b1 100644 --- a/arch/sparc/kernel/syscalls/syscall.tbl +++ b/arch/sparc/kernel/syscalls/syscall.tbl @@ -508,3 +508,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index d6ebcab1d8b2..c4fc7c4f65c3 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -467,3 +467,4 @@ 460 i386 lsm_set_self_attr sys_lsm_set_self_attr 461 i386 lsm_list_modules sys_lsm_list_modules 462 i386 mseal sys_mseal +463 i386 vgetrandom_alloc sys_vgetrandom_alloc diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index a396f6e6ab5b..441443ba2ae6 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -384,6 +384,7 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc # # Due to a historical design error, certain syscalls are numbered differently diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl index 67083fc1b2f5..b9f64edd0b18 100644 --- a/arch/xtensa/kernel/syscalls/syscall.tbl +++ b/arch/xtensa/kernel/syscalls/syscall.tbl @@ -433,3 +433,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index d4cc26932ff4..57371c90dc13 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -845,8 +845,11 @@ __SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules) #define __NR_mseal 462 __SYSCALL(__NR_mseal, sys_mseal) +#define __NR_vgetrandom_alloc 463 +__SYSCALL(__NR_vgetrandom_alloc, sys_vgetrandom_alloc) + #undef __NR_syscalls -#define __NR_syscalls 463 +#define __NR_syscalls 464 /* * 32 bit systems traditionally used different diff --git a/tools/include/uapi/asm-generic/unistd.h b/tools/include/uapi/asm-generic/unistd.h index d983c48a3b6a..e94210483f60 100644 --- a/tools/include/uapi/asm-generic/unistd.h +++ b/tools/include/uapi/asm-generic/unistd.h @@ -845,8 +845,11 @@ __SYSCALL(__NR_lsm_list_modules, sys_lsm_list_modules) #define __NR_mseal 462 __SYSCALL(__NR_mseal, sys_mseal) +#define __NR_vgetrandom_alloc 463 +__SYSCALL(__NR_vgetrandom_alloc, sys_vgetrandom_alloc) + #undef __NR_syscalls -#define __NR_syscalls 463 +#define __NR_syscalls 464 /* * 32 bit systems traditionally used different diff --git a/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl b/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl index 1464c6be6eb3..33710f855c46 100644 --- a/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl +++ b/tools/perf/arch/mips/entry/syscalls/syscall_n64.tbl @@ -377,3 +377,4 @@ 460 n64 lsm_set_self_attr sys_lsm_set_self_attr 461 n64 lsm_list_modules sys_lsm_list_modules 462 n64 mseal sys_mseal +463 n64 vgetrandom_alloc sys_vgetrandom_alloc diff --git a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl index 3656f1ca7a21..b1c3ae68014c 100644 --- a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl +++ b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl @@ -549,3 +549,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc diff --git a/tools/perf/arch/s390/entry/syscalls/syscall.tbl b/tools/perf/arch/s390/entry/syscalls/syscall.tbl index bd0fee24ad10..1188429316c1 100644 --- a/tools/perf/arch/s390/entry/syscalls/syscall.tbl +++ b/tools/perf/arch/s390/entry/syscalls/syscall.tbl @@ -465,3 +465,4 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc sys_vgetrandom_alloc diff --git a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl index a396f6e6ab5b..441443ba2ae6 100644 --- a/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl +++ b/tools/perf/arch/x86/entry/syscalls/syscall_64.tbl @@ -384,6 +384,7 @@ 460 common lsm_set_self_attr sys_lsm_set_self_attr 461 common lsm_list_modules sys_lsm_list_modules 462 common mseal sys_mseal +463 common vgetrandom_alloc sys_vgetrandom_alloc # # Due to a historical design error, certain syscalls are numbered differently From patchwork Wed Jul 3 18:31:14 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 809467 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DAA3D18509A; Wed, 3 Jul 2024 18:32:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031531; cv=none; b=E5RfCwRwsj5FlZTCE/N7+CdsJUE4Px6u/bXMrKbu9NwddS51oSeG/PVaneRc2epjWIiQJqrM/TJjtrHcA6PZHHLAvDxzCAAur5zr9boAMURMVzvGIhh7HdbmVWydbz1/T/NOX+Y5vYeIezp3pkHb/SL4O+9mE3EeHpz5m43ptTM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720031531; c=relaxed/simple; bh=WlO1c69z+1VfvDEtT0E66MNBJIGlQPl6anecoB6uI4o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=U/OjuwceSLv6NBQJ0GiO6V+Hn1b3ITcifqpWffJXro06zDss80tXwr0ZeC4tLgOnHIT4To/fLgsfr+34x+1nqe9sCUL+TSa5Ot/QBI62iDMMK31f7uEuWFhubfWfh5SColmvWBRsjMn44BTzPVCgvsfVD8280fd444acygM3LHE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=G4R7hq0t; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="G4R7hq0t" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C80FC4AF0A; Wed, 3 Jul 2024 18:32:09 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="G4R7hq0t" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1720031528; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BBqqEC/LRLHybwsJOCYGax29ShdUGaaeOYWEFD/HOFs=; b=G4R7hq0thZPEZ/FmGDeg2uqARvZtlxyJ/Dg4S9VShEWNU5nzZE9qOHMOJRauOpXO2kEN4r SeG+BcSIXs4Ye6Lb85WpRoMQdb1KFYr1eacbn5bhUcvfwz+uOha6+1dg0fbp8pfl7v1xXI WgnYX3ndLgAK24lZfWTxCkYnjkyRQVg= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 35a51631 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Wed, 3 Jul 2024 18:32:07 +0000 (UTC) From: "Jason A. Donenfeld" To: linux-kernel@vger.kernel.org, patches@lists.linux.dev, tglx@linutronix.de Cc: "Jason A. Donenfeld" , linux-crypto@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, Greg Kroah-Hartman , Adhemerval Zanella Netto , Carlos O'Donell , Florian Weimer , Arnd Bergmann , Jann Horn , Christian Brauner , David Hildenbrand , Samuel Neves Subject: [PATCH v20 5/5] x86: vdso: Wire up getrandom() vDSO implementation Date: Wed, 3 Jul 2024 20:31:14 +0200 Message-ID: <20240703183115.1075219-6-Jason@zx2c4.com> In-Reply-To: <20240703183115.1075219-1-Jason@zx2c4.com> References: <20240703183115.1075219-1-Jason@zx2c4.com> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Hook up the generic vDSO implementation to the x86 vDSO data page. Since the existing vDSO infrastructure is heavily based on the timekeeping functionality, which works over arrays of bases, a new macro is introduced for vvars that are not arrays. The vDSO function requires a ChaCha20 implementation that does not write to the stack, yet can still do an entire ChaCha20 permutation, so provide this using SSE2, since this is userland code that must work on all x86-64 processors. There's a simple test for this code as well. Reviewed-by: Thomas Gleixner Reviewed-by: Samuel Neves # for vgetrandom-chacha.S Signed-off-by: Jason A. Donenfeld --- MAINTAINERS | 2 + arch/x86/Kconfig | 1 + arch/x86/entry/vdso/Makefile | 3 +- arch/x86/entry/vdso/vdso.lds.S | 2 + arch/x86/entry/vdso/vgetrandom-chacha.S | 178 ++++++++++++++++++ arch/x86/entry/vdso/vgetrandom.c | 17 ++ arch/x86/include/asm/vdso/getrandom.h | 55 ++++++ arch/x86/include/asm/vdso/vsyscall.h | 2 + arch/x86/include/asm/vvar.h | 16 ++ tools/testing/selftests/vDSO/.gitignore | 1 + tools/testing/selftests/vDSO/Makefile | 15 ++ .../testing/selftests/vDSO/vdso_test_chacha.c | 43 +++++ 12 files changed, 334 insertions(+), 1 deletion(-) create mode 100644 arch/x86/entry/vdso/vgetrandom-chacha.S create mode 100644 arch/x86/entry/vdso/vgetrandom.c create mode 100644 arch/x86/include/asm/vdso/getrandom.h create mode 100644 tools/testing/selftests/vDSO/vdso_test_chacha.c diff --git a/MAINTAINERS b/MAINTAINERS index 798158329ad8..00cf0362482b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18749,6 +18749,8 @@ F: drivers/char/random.c F: drivers/virt/vmgenid.c F: include/vdso/getrandom.h F: lib/vdso/getrandom.c +F: arch/x86/entry/vdso/vgetrandom* +F: arch/x86/include/asm/vdso/getrandom* RAPIDIO SUBSYSTEM M: Matt Porter diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 1d7122a1883e..9c98b7a88cc2 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -287,6 +287,7 @@ config X86 select HAVE_UNSTABLE_SCHED_CLOCK select HAVE_USER_RETURN_NOTIFIER select HAVE_GENERIC_VDSO + select VDSO_GETRANDOM if X86_64 select HOTPLUG_PARALLEL if SMP && X86_64 select HOTPLUG_SMT if SMP select HOTPLUG_SPLIT_STARTUP if SMP && X86_32 diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 215a1b202a91..c9216ac4fb1e 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -7,7 +7,7 @@ include $(srctree)/lib/vdso/Makefile # Files to link into the vDSO: -vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o +vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vgetrandom.o vgetrandom-chacha.o vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o vobjs32-y += vdso32/vclock_gettime.o vdso32/vgetcpu.o vobjs-$(CONFIG_X86_SGX) += vsgx.o @@ -73,6 +73,7 @@ CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg CFLAGS_REMOVE_vgetcpu.o = -pg CFLAGS_REMOVE_vdso32/vgetcpu.o = -pg CFLAGS_REMOVE_vsgx.o = -pg +CFLAGS_REMOVE_vgetrandom.o = -pg # # X32 processes use x32 vDSO to access 64bit kernel data. diff --git a/arch/x86/entry/vdso/vdso.lds.S b/arch/x86/entry/vdso/vdso.lds.S index e8c60ae7a7c8..0bab5f4af6d1 100644 --- a/arch/x86/entry/vdso/vdso.lds.S +++ b/arch/x86/entry/vdso/vdso.lds.S @@ -30,6 +30,8 @@ VERSION { #ifdef CONFIG_X86_SGX __vdso_sgx_enter_enclave; #endif + getrandom; + __vdso_getrandom; local: *; }; } diff --git a/arch/x86/entry/vdso/vgetrandom-chacha.S b/arch/x86/entry/vdso/vgetrandom-chacha.S new file mode 100644 index 000000000000..bcba5639b8ee --- /dev/null +++ b/arch/x86/entry/vdso/vgetrandom-chacha.S @@ -0,0 +1,178 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022-2024 Jason A. Donenfeld . All Rights Reserved. + */ + +#include +#include + +.section .rodata, "a" +.align 16 +CONSTANTS: .octa 0x6b20657479622d323320646e61707865 +.text + +/* + * Very basic SSE2 implementation of ChaCha20. Produces a given positive number + * of blocks of output with a nonce of 0, taking an input key and 8-byte + * counter. Importantly does not spill to the stack. Its arguments are: + * + * rdi: output bytes + * rsi: 32-byte key input + * rdx: 8-byte counter input/output + * rcx: number of 64-byte blocks to write to output + */ +SYM_FUNC_START(__arch_chacha20_blocks_nostack) + +.set output, %rdi +.set key, %rsi +.set counter, %rdx +.set nblocks, %rcx +.set i, %al +/* xmm registers are *not* callee-save. */ +.set temp, %xmm0 +.set state0, %xmm1 +.set state1, %xmm2 +.set state2, %xmm3 +.set state3, %xmm4 +.set copy0, %xmm5 +.set copy1, %xmm6 +.set copy2, %xmm7 +.set copy3, %xmm8 +.set one, %xmm9 + + /* copy0 = "expand 32-byte k" */ + movaps CONSTANTS(%rip),copy0 + /* copy1,copy2 = key */ + movups 0x00(key),copy1 + movups 0x10(key),copy2 + /* copy3 = counter || zero nonce */ + movq 0x00(counter),copy3 + /* one = 1 || 0 */ + movq $1,%rax + movq %rax,one + +.Lblock: + /* state0,state1,state2,state3 = copy0,copy1,copy2,copy3 */ + movdqa copy0,state0 + movdqa copy1,state1 + movdqa copy2,state2 + movdqa copy3,state3 + + movb $10,i +.Lpermute: + /* state0 += state1, state3 = rotl32(state3 ^ state0, 16) */ + paddd state1,state0 + pxor state0,state3 + movdqa state3,temp + pslld $16,temp + psrld $16,state3 + por temp,state3 + + /* state2 += state3, state1 = rotl32(state1 ^ state2, 12) */ + paddd state3,state2 + pxor state2,state1 + movdqa state1,temp + pslld $12,temp + psrld $20,state1 + por temp,state1 + + /* state0 += state1, state3 = rotl32(state3 ^ state0, 8) */ + paddd state1,state0 + pxor state0,state3 + movdqa state3,temp + pslld $8,temp + psrld $24,state3 + por temp,state3 + + /* state2 += state3, state1 = rotl32(state1 ^ state2, 7) */ + paddd state3,state2 + pxor state2,state1 + movdqa state1,temp + pslld $7,temp + psrld $25,state1 + por temp,state1 + + /* state1[0,1,2,3] = state1[1,2,3,0] */ + pshufd $0x39,state1,state1 + /* state2[0,1,2,3] = state2[2,3,0,1] */ + pshufd $0x4e,state2,state2 + /* state3[0,1,2,3] = state3[3,0,1,2] */ + pshufd $0x93,state3,state3 + + /* state0 += state1, state3 = rotl32(state3 ^ state0, 16) */ + paddd state1,state0 + pxor state0,state3 + movdqa state3,temp + pslld $16,temp + psrld $16,state3 + por temp,state3 + + /* state2 += state3, state1 = rotl32(state1 ^ state2, 12) */ + paddd state3,state2 + pxor state2,state1 + movdqa state1,temp + pslld $12,temp + psrld $20,state1 + por temp,state1 + + /* state0 += state1, state3 = rotl32(state3 ^ state0, 8) */ + paddd state1,state0 + pxor state0,state3 + movdqa state3,temp + pslld $8,temp + psrld $24,state3 + por temp,state3 + + /* state2 += state3, state1 = rotl32(state1 ^ state2, 7) */ + paddd state3,state2 + pxor state2,state1 + movdqa state1,temp + pslld $7,temp + psrld $25,state1 + por temp,state1 + + /* state1[0,1,2,3] = state1[3,0,1,2] */ + pshufd $0x93,state1,state1 + /* state2[0,1,2,3] = state2[2,3,0,1] */ + pshufd $0x4e,state2,state2 + /* state3[0,1,2,3] = state3[1,2,3,0] */ + pshufd $0x39,state3,state3 + + decb i + jnz .Lpermute + + /* output0 = state0 + copy0 */ + paddd copy0,state0 + movups state0,0x00(output) + /* output1 = state1 + copy1 */ + paddd copy1,state1 + movups state1,0x10(output) + /* output2 = state2 + copy2 */ + paddd copy2,state2 + movups state2,0x20(output) + /* output3 = state3 + copy3 */ + paddd copy3,state3 + movups state3,0x30(output) + + /* ++copy3.counter */ + paddq one,copy3 + + /* output += 64, --nblocks */ + addq $64,output + decq nblocks + jnz .Lblock + + /* counter = copy3.counter */ + movq copy3,0x00(counter) + + /* Zero out the potentially sensitive regs, in case nothing uses these again. */ + pxor state0,state0 + pxor state1,state1 + pxor state2,state2 + pxor state3,state3 + pxor copy1,copy1 + pxor copy2,copy2 + pxor temp,temp + + ret +SYM_FUNC_END(__arch_chacha20_blocks_nostack) diff --git a/arch/x86/entry/vdso/vgetrandom.c b/arch/x86/entry/vdso/vgetrandom.c new file mode 100644 index 000000000000..52d3c7faae2e --- /dev/null +++ b/arch/x86/entry/vdso/vgetrandom.c @@ -0,0 +1,17 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2022-2024 Jason A. Donenfeld . All Rights Reserved. + */ +#include + +#include "../../../../lib/vdso/getrandom.c" + +ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len); + +ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len) +{ + return __cvdso_getrandom(buffer, len, flags, opaque_state, opaque_len); +} + +ssize_t getrandom(void *, size_t, unsigned int, void *, size_t) + __attribute__((weak, alias("__vdso_getrandom"))); diff --git a/arch/x86/include/asm/vdso/getrandom.h b/arch/x86/include/asm/vdso/getrandom.h new file mode 100644 index 000000000000..b96e674cafde --- /dev/null +++ b/arch/x86/include/asm/vdso/getrandom.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2022-2024 Jason A. Donenfeld . All Rights Reserved. + */ +#ifndef __ASM_VDSO_GETRANDOM_H +#define __ASM_VDSO_GETRANDOM_H + +#ifndef __ASSEMBLY__ + +#include +#include + +/** + * getrandom_syscall - Invoke the getrandom() syscall. + * @buffer: Destination buffer to fill with random bytes. + * @len: Size of @buffer in bytes. + * @flags: Zero or more GRND_* flags. + * Returns: The number of random bytes written to @buffer, or a negative value indicating an error. + */ +static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags) +{ + long ret; + + asm ("syscall" : "=a" (ret) : + "0" (__NR_getrandom), "D" (buffer), "S" (len), "d" (flags) : + "rcx", "r11", "memory"); + + return ret; +} + +#define __vdso_rng_data (VVAR(_vdso_rng_data)) + +static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void) +{ + if (IS_ENABLED(CONFIG_TIME_NS) && __vdso_data->clock_mode == VDSO_CLOCKMODE_TIMENS) + return (void *)&__vdso_rng_data + ((void *)&__timens_vdso_data - (void *)&__vdso_data); + return &__vdso_rng_data; +} + +/** + * __arch_chacha20_blocks_nostack - Generate ChaCha20 stream without using the stack. + * @dst_bytes: Destination buffer to hold @nblocks * 64 bytes of output. + * @key: 32-byte input key. + * @counter: 8-byte counter, read on input and updated on return. + * @nblocks: Number of blocks to generate. + * + * Generates a given positive number of blocks of ChaCha20 output with nonce=0, and does not write + * to any stack or memory outside of the parameters passed to it, in order to mitigate stack data + * leaking into forked child processes. + */ +extern void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks); + +#endif /* !__ASSEMBLY__ */ + +#endif /* __ASM_VDSO_GETRANDOM_H */ diff --git a/arch/x86/include/asm/vdso/vsyscall.h b/arch/x86/include/asm/vdso/vsyscall.h index be199a9b2676..71c56586a22f 100644 --- a/arch/x86/include/asm/vdso/vsyscall.h +++ b/arch/x86/include/asm/vdso/vsyscall.h @@ -11,6 +11,8 @@ #include DEFINE_VVAR(struct vdso_data, _vdso_data); +DEFINE_VVAR_SINGLE(struct vdso_rng_data, _vdso_rng_data); + /* * Update the vDSO data page to keep in sync with kernel timekeeping. */ diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h index 183e98e49ab9..9d9af37f7cab 100644 --- a/arch/x86/include/asm/vvar.h +++ b/arch/x86/include/asm/vvar.h @@ -26,6 +26,8 @@ */ #define DECLARE_VVAR(offset, type, name) \ EMIT_VVAR(name, offset) +#define DECLARE_VVAR_SINGLE(offset, type, name) \ + EMIT_VVAR(name, offset) #else @@ -37,6 +39,10 @@ extern char __vvar_page; extern type timens_ ## name[CS_BASES] \ __attribute__((visibility("hidden"))); \ +#define DECLARE_VVAR_SINGLE(offset, type, name) \ + extern type vvar_ ## name \ + __attribute__((visibility("hidden"))); \ + #define VVAR(name) (vvar_ ## name) #define TIMENS(name) (timens_ ## name) @@ -44,12 +50,22 @@ extern char __vvar_page; type name[CS_BASES] \ __attribute__((section(".vvar_" #name), aligned(16))) __visible +#define DEFINE_VVAR_SINGLE(type, name) \ + type name \ + __attribute__((section(".vvar_" #name), aligned(16))) __visible + #endif /* DECLARE_VVAR(offset, type, name) */ DECLARE_VVAR(128, struct vdso_data, _vdso_data) +#if !defined(_SINGLE_DATA) +#define _SINGLE_DATA +DECLARE_VVAR_SINGLE(640, struct vdso_rng_data, _vdso_rng_data) +#endif + #undef DECLARE_VVAR +#undef DECLARE_VVAR_SINGLE #endif diff --git a/tools/testing/selftests/vDSO/.gitignore b/tools/testing/selftests/vDSO/.gitignore index 7dbfdec53f3d..30d5c8f0e5c7 100644 --- a/tools/testing/selftests/vDSO/.gitignore +++ b/tools/testing/selftests/vDSO/.gitignore @@ -7,3 +7,4 @@ vdso_test_gettimeofday vdso_test_getcpu vdso_standalone_test_x86 vdso_test_getrandom +vdso_test_chacha diff --git a/tools/testing/selftests/vDSO/Makefile b/tools/testing/selftests/vDSO/Makefile index fd7c29d9814b..f828e0a9d498 100644 --- a/tools/testing/selftests/vDSO/Makefile +++ b/tools/testing/selftests/vDSO/Makefile @@ -3,6 +3,7 @@ include ../lib.mk uname_M := $(shell uname -m 2>/dev/null || echo not) ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/) +SODIUM := $(shell pkg-config --libs libsodium 2>/dev/null) TEST_GEN_PROGS := $(OUTPUT)/vdso_test_gettimeofday $(OUTPUT)/vdso_test_getcpu TEST_GEN_PROGS += $(OUTPUT)/vdso_test_abi @@ -12,10 +13,18 @@ TEST_GEN_PROGS += $(OUTPUT)/vdso_standalone_test_x86 endif TEST_GEN_PROGS += $(OUTPUT)/vdso_test_correctness TEST_GEN_PROGS += $(OUTPUT)/vdso_test_getrandom +ifeq ($(uname_M),x86_64) +ifneq ($(SODIUM),) +TEST_GEN_PROGS += $(OUTPUT)/vdso_test_chacha +endif +endif CFLAGS := -std=gnu99 CFLAGS_vdso_standalone_test_x86 := -nostdlib -fno-asynchronous-unwind-tables -fno-stack-protector CFLAGS_vdso_test_getrandom := -isystem $(top_srcdir)/tools/include -isystem $(top_srcdir)/include/uapi +CFLAGS_vdso_test_chacha := $(SODIUM) -idirafter $(top_srcdir)/include -idirafter \ + $(top_srcdir)/arch/$(ARCH)/include -idirafter include \ + -D__ASSEMBLY__ -DBULID_VDSO -DCONFIG_FUNCTION_ALIGNMENT=0 -Wa,--noexecstack LDFLAGS_vdso_test_correctness := -ldl ifeq ($(CONFIG_X86_32),y) LDLIBS += -lgcc_s @@ -37,3 +46,9 @@ $(OUTPUT)/vdso_test_correctness: vdso_test_correctness.c $(LDFLAGS_vdso_test_correctness) $(OUTPUT)/vdso_test_getrandom: CFLAGS += $(CFLAGS_vdso_test_getrandom) $(OUTPUT)/vdso_test_getrandom: parse_vdso.c +$(OUTPUT)/vdso_test_chacha: CFLAGS += $(CFLAGS_vdso_test_chacha) +$(OUTPUT)/vdso_test_chacha: $(top_srcdir)/arch/$(ARCH)/entry/vdso/vgetrandom-chacha.S +$(OUTPUT)/vdso_test_chacha: include/asm/rwonce.h +include/asm/rwonce.h: + mkdir -p include/asm + touch $@ diff --git a/tools/testing/selftests/vDSO/vdso_test_chacha.c b/tools/testing/selftests/vDSO/vdso_test_chacha.c new file mode 100644 index 000000000000..e38f44e5f803 --- /dev/null +++ b/tools/testing/selftests/vDSO/vdso_test_chacha.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2022-2024 Jason A. Donenfeld . All Rights Reserved. + */ + +#include +#include +#include +#include +#include "../kselftest.h" + +extern void __arch_chacha20_blocks_nostack(uint8_t *dst_bytes, const uint8_t *key, uint32_t *counter, size_t nblocks); + +int main(int argc, char *argv[]) +{ + enum { TRIALS = 1000, BLOCKS = 128, BLOCK_SIZE = 64 }; + static const uint8_t nonce[8] = { 0 }; + uint32_t counter[2]; + uint8_t key[32]; + uint8_t output1[BLOCK_SIZE * BLOCKS], output2[BLOCK_SIZE * BLOCKS]; + + ksft_print_header(); + ksft_set_plan(1); + + for (unsigned int trial = 0; trial < TRIALS; ++trial) { + if (getrandom(key, sizeof(key), 0) != sizeof(key)) { + printf("getrandom() failed!\n"); + return KSFT_SKIP; + } + crypto_stream_chacha20(output1, sizeof(output1), nonce, key); + for (unsigned int split = 0; split < BLOCKS; ++split) { + memset(output2, 'X', sizeof(output2)); + memset(counter, 0, sizeof(counter)); + if (split) + __arch_chacha20_blocks_nostack(output2, key, counter, split); + __arch_chacha20_blocks_nostack(output2 + split * BLOCK_SIZE, key, counter, BLOCKS - split); + if (memcmp(output1, output2, sizeof(output1))) + return KSFT_FAIL; + } + } + ksft_test_result_pass("chacha: PASS\n"); + return KSFT_PASS; +}