From: Jeff Xu jeffxu@google.com

This patch enables PKEY_ENFORCE_API for the mprotect and mprotect_pkey syscalls.

Signed-off-by: Jeff Xujeffxu@google.com --- mm/mprotect.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/mm/mprotect.c b/mm/mprotect.c index 8a68fdca8487..1378be50567d 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -727,9 +727,13 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,

/* * pkey==-1 when doing a legacy mprotect() + * syscall==true if this is called by syscall from userspace. + * Note: this is always true for now, added as a reminder in case that + * do_mprotect_pkey is called directly by kernel in the future. + * Also it is consistent with __do_munmap(). */ static int do_mprotect_pkey(unsigned long start, size_t len, - unsigned long prot, int pkey) + unsigned long prot, int pkey, bool syscall) { unsigned long nstart, end, tmp, reqprot; struct vm_area_struct *vma, *prev; @@ -794,6 +798,21 @@ static int do_mprotect_pkey(unsigned long start, size_t len, } }

+ /* + * When called by syscall from userspace, check if the calling + * thread has the PKEY permission to modify the memory mapping. + */ + if (syscall && + arch_check_pkey_enforce_api(current->mm, start, end) < 0) { + char comm[TASK_COMM_LEN]; + + pr_warn_ratelimited( + "munmap was denied on PKEY_ENFORCE_API memory, pid=%d '%s'\n", + task_pid_nr(current), get_task_comm(comm, current)); + error = -EACCES; + goto out; + } + prev = vma_prev(&vmi); if (start > vma->vm_start) prev = vma; @@ -878,7 +897,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len, SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, unsigned long, prot) { - return do_mprotect_pkey(start, len, prot, -1); + return do_mprotect_pkey(start, len, prot, -1, true); }

#ifdef CONFIG_ARCH_HAS_PKEYS @@ -886,7 +905,7 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len, unsigned long, prot, int, pkey) { - return do_mprotect_pkey(start, len, prot, pkey); + return do_mprotect_pkey(start, len, prot, pkey, true); }

SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)

From: Jeff Xu jeffxu@google.com

Add selftest for pkey_enforce_api for mprotect.

Signed-off-by: Jeff Xujeffxu@google.com --- tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/pkey_enforce_api.c | 875 ++++++++++++++++++ 2 files changed, 876 insertions(+) create mode 100644 tools/testing/selftests/mm/pkey_enforce_api.c

diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index 23af4633f0f4..93437a394128 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -71,6 +71,7 @@ CAN_BUILD_X86_64 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_64bit_pr CAN_BUILD_WITH_NOPIE := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_program.c -no-pie)

VMTARGETS := protection_keys +VMTARGETS += pkey_enforce_api BINARIES_32 := $(VMTARGETS:%=%_32) BINARIES_64 := $(VMTARGETS:%=%_64)

diff --git a/tools/testing/selftests/mm/pkey_enforce_api.c b/tools/testing/selftests/mm/pkey_enforce_api.c new file mode 100644 index 000000000000..23663c89bc9c --- /dev/null +++ b/tools/testing/selftests/mm/pkey_enforce_api.c @@ -0,0 +1,875 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Tests pkey_enforce_api + * + * Compile like this: + * gcc -mxsave -o pkey_enforce_api -O2 -g -std=gnu99 -pthread -Wall pkey_enforce_api.c \ + * -lrt -ldl -lm + * gcc -mxsave -m32 -o pkey_enforce_api_32 -O2 -g -std=gnu99 -pthread -Wall pkey_enforce_api.c \ + * -lrt -ldl -lm + */ +#define _GNU_SOURCE +#define __SANE_USERSPACE_TYPES__ +#include <errno.h> +#include <linux/elf.h> +#include <linux/futex.h> +#include <pthread.h> +#include <time.h> +#include <sys/time.h> +#include <sys/syscall.h> +#include <string.h> +#include <stdio.h> +#include <stdint.h> +#include <stdbool.h> +#include <signal.h> +#include <assert.h> +#include <stdlib.h> +#include <ucontext.h> +#include <sys/mman.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <unistd.h> +#include <sys/ptrace.h> +#include <setjmp.h> +#include "../kselftest.h" +#include <sys/prctl.h> + +#if defined(__i386__) || defined(__x86_64__) /* arch */ + +#define dprintf0(args...) +#define dprintf1(args...) +#define dprintf2(args...) +#define dprintf3(args...) +#define dprintf4(args...) + +#ifndef u16 +#define u16 __u16 +#endif + +#ifndef u32 +#define u32 __u32 +#endif + +#ifndef u64 +#define u64 __u64 +#endif + +#ifndef PTR_ERR_ENOTSUP +#define PTR_ERR_ENOTSUP ((void *)-ENOTSUP) +#endif + +int read_ptr(int *ptr) +{ + return *ptr; +} + +void expected_pkey_fault(int pkey) +{ +} + +#include "pkey-x86.h" + +#ifndef PKEY_ENFORCE_API +#define PKEY_ENFORCE_API 1 +#endif + +#define PKEY_MASK (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE) + +#define LOG_TEST_ENTER(x) \ + { \ + printf("%s, enforce=%d\n", __func__, x); \ + } +static inline u64 set_pkey_bits(u64 reg, int pkey, u64 flags) +{ + u32 shift = pkey_bit_position(pkey); + /* mask out bits from pkey in old value */ + reg &= ~((u64)PKEY_MASK << shift); + /* OR in new bits for pkey */ + reg |= (flags & PKEY_MASK) << shift; + return reg; +} + +static inline u64 get_pkey_bits(u64 reg, int pkey) +{ + u32 shift = pkey_bit_position(pkey); + /* + * shift down the relevant bits to the lowest two, then + * mask off all the other higher bits + */ + return ((reg >> shift) & PKEY_MASK); +} + +static u32 get_pkey(int pkey) +{ + return (u32)get_pkey_bits(__read_pkey_reg(), pkey); +} + +static void set_pkey(int pkey, unsigned long pkey_value) +{ + u32 mask = (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE); + u64 new_pkey_reg; + + assert(!(pkey_value & ~mask)); + new_pkey_reg = set_pkey_bits(__read_pkey_reg(), pkey, pkey_value); + __write_pkey_reg(new_pkey_reg); +} + +void pkey_disable_set(int pkey, int value) +{ + int pkey_new; + + assert(value & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE)); + + pkey_new = get_pkey(pkey); + pkey_new |= value; + set_pkey(pkey, pkey_new); +} + +void pkey_disable_clear(int pkey, int value) +{ + int pkey_new; + + assert(value & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE)); + + pkey_new = get_pkey(pkey); + pkey_new &= ~value; + + set_pkey(pkey, pkey_new); +} + +void pkey_write_allow(int pkey) +{ + pkey_disable_clear(pkey, PKEY_DISABLE_WRITE); +} +void pkey_write_deny(int pkey) +{ + pkey_disable_set(pkey, PKEY_DISABLE_WRITE); +} +void pkey_access_allow(int pkey) +{ + pkey_disable_clear(pkey, PKEY_DISABLE_ACCESS); +} +void pkey_access_deny(int pkey) +{ + pkey_disable_set(pkey, PKEY_DISABLE_ACCESS); +} + +int sys_mprotect(void *ptr, size_t size, unsigned long prot) +{ + int sret; + + errno = 0; + sret = syscall(SYS_mprotect, ptr, size, prot); + return sret; +} + +int sys_mprotect_pkey(void *ptr, size_t size, unsigned long orig_prot, + unsigned long pkey) +{ + int sret; + + errno = 0; + sret = syscall(SYS_mprotect_key, ptr, size, orig_prot, pkey); + return sret; +} + +int sys_pkey_alloc(unsigned long flags, unsigned long init_val) +{ + int ret = syscall(SYS_pkey_alloc, flags, init_val); + return ret; +} + +int sys_pkey_free(unsigned long pkey) +{ + int ret = syscall(SYS_pkey_free, pkey); + return ret; +} + +bool can_create_pkey(void) +{ + int pkey; + + pkey = sys_pkey_alloc(0, 0); + if (pkey <= 0) + return false; + + sys_pkey_free(pkey); + return true; +} + +static inline int is_pkeys_supported(void) +{ + /* check if the cpu supports pkeys */ + if (!cpu_has_pkeys() || !can_create_pkey()) + return 0; + return 1; +} + +int pkey_alloc_with_check(bool enforce) +{ + int pkey; + + if (enforce) + pkey = sys_pkey_alloc(PKEY_ENFORCE_API, 0); + else + pkey = sys_pkey_alloc(0, 0); + + assert(pkey > 0); + return pkey; +} + +void *addr1 = (void *)0x5000000; +void *addr2 = (void *)0x5001000; +void *addr3 = (void *)0x5002000; +void *addr4 = (void *)0x5003000; + +void setup_single_address_with_pkey(bool enforce, int size, int *pkeyOut, + void **ptrOut) +{ + int pkey; + void *ptr; + int ret; + + pkey = pkey_alloc_with_check(enforce); + + ptr = mmap(NULL, size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + assert(ptr != (void *)-1); + + // assign pkey to the memory. + ret = sys_mprotect_pkey((void *)ptr, size, PROT_READ, pkey); + assert(!ret); + + *pkeyOut = pkey; + *ptrOut = ptr; +} + +void setup_single_fixed_address_with_pkey(bool enforce, int size, int *pkeyOut, + void **ptrOut) +{ + int pkey; + void *ptr; + int ret; + + pkey = pkey_alloc_with_check(enforce); + + ptr = mmap(addr1, size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + assert(ptr == (void *)addr1); + + // assign pkey to the memory. + ret = sys_mprotect_pkey((void *)ptr, size, PROT_READ, pkey); + assert(!ret); + + *pkeyOut = pkey; + *ptrOut = ptr; +} + +void clean_single_address_with_pkey(int pkey, void *ptr, int size) +{ + int ret; + + ret = munmap(ptr, size); + assert(!ret); + + ret = sys_pkey_free(pkey); + assert(ret == 0); +} + +void setup_two_continues_fixed_address_with_pkey(bool enforce, int size, + int *pkeyOut, void **ptrOut, + void **ptr2Out) +{ + void *ptr; + void *ptr2; + int pkey; + int ret; + + pkey = pkey_alloc_with_check(enforce); + + ptr = mmap(addr1, size, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + assert(ptr == addr1); + + ptr2 = mmap(addr2, size, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + assert(ptr2 == addr2); + + // assign pkey to both addresses in the same call (merged) + ret = sys_mprotect_pkey(ptr, size * 2, + PROT_READ | PROT_WRITE | PROT_EXEC, pkey); + assert(!ret); + *pkeyOut = pkey; + *ptrOut = ptr; + *ptr2Out = ptr2; +} + +void clean_two_address_with_pkey(int size, int pkey, void *ptr, void *ptr2) +{ + int ret; + + ret = munmap(ptr, size); + assert(!ret); + + ret = munmap(ptr2, size); + assert(!ret); + + ret = sys_pkey_free(pkey); + assert(ret == 0); +} + +// pkey_alloc with flags. +void test_pkey_alloc(bool enforce) +{ + int ret; + + LOG_TEST_ENTER(enforce); + + ret = sys_pkey_alloc(0, 0); + assert(ret > 0); + ret = sys_pkey_free(ret); + assert(ret == 0); + + if (enforce) { + ret = sys_pkey_alloc(PKEY_ENFORCE_API, 0); + assert(ret > 0); + ret = sys_pkey_free(ret); + assert(ret == 0); + + // invalid flag. + ret = sys_pkey_alloc(0x4, 0); + assert(ret != 0); + } +} + +// mmap one address. +// assign pkey on the address. +// mprotect is denied when no-writeable PKRU in enforce mode. +void test_mprotect_single_address(bool enforce) +{ + int pkey; + int ret; + void *ptr; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_single_fixed_address_with_pkey(enforce, size, &pkey, &ptr); + + // disable write access. + pkey_write_deny(pkey); + + ret = sys_mprotect_pkey(ptr, size, PROT_READ | PROT_WRITE, pkey); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + ret = sys_mprotect(ptr, size, PROT_READ | PROT_WRITE); + if (enforce) + assert(ret < 0); + else + assert(ret == 0); + + pkey_write_allow(pkey); + + ret = sys_mprotect_pkey(ptr, size, PROT_READ, pkey); + assert(!ret); + + ret = sys_mprotect(ptr, size, PROT_READ); + assert(ret == 0); + + clean_single_address_with_pkey(pkey, ptr, size); +} + +// mmap two address (continuous two pages). +// assign PKEY to them with one mprotect_pkey call (merged address). +// mprotect is denied when non-writeable PKRU in enforce mode. +void test_mprotect_two_address_merge(bool enforce) +{ + int pkey; + int ret; + void *ptr; + void *ptr2; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_two_continues_fixed_address_with_pkey(enforce, size, &pkey, &ptr, + &ptr2); + + // disable write. + pkey_write_deny(pkey); + + // modify the protection on both addresses (merged). + ret = sys_mprotect(ptr, size * 2, PROT_READ | PROT_WRITE | PROT_EXEC); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + ret = sys_mprotect_pkey(ptr, size * 2, + PROT_READ | PROT_WRITE | PROT_EXEC, pkey); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + // modify the protection on both addresses (merged). + ret = sys_mprotect(ptr, size * 2, PROT_READ | PROT_WRITE | PROT_EXEC); + assert(!ret); + + ret = sys_mprotect_pkey(ptr, size * 2, + PROT_READ | PROT_WRITE | PROT_EXEC, pkey); + assert(!ret); + + clean_two_address_with_pkey(size, pkey, ptr, ptr2); +} + +void setup_two_continues_fixed_address_protect_second_with_pkey( + bool enforce, int size, int *pkeyOut, void **ptrOut, void **ptr2Out) +{ + void *ptr; + void *ptr2; + int pkey; + int ret; + + LOG_TEST_ENTER(enforce); + + pkey = pkey_alloc_with_check(enforce); + + // mmap two addresses (continuous two pages). + ptr = mmap(addr1, size, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + assert(ptr == addr1); + + ptr2 = mmap(addr2, size, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + assert(ptr2 == addr2); + + // assign pkey to the second page. + ret = sys_mprotect_pkey(addr2, size, PROT_READ | PROT_WRITE | PROT_EXEC, + pkey); + assert(!ret); + + *pkeyOut = pkey; + *ptrOut = ptr; + *ptr2Out = ptr2; +} + +// mmap two address (continuous two pages). +// assign PKEY to the second address. +// mprotect on the second address is denied properly. +// mprotect on both addresses (merged) is denied properly. +void test_mprotect_two_address_deny_second(bool enforce) +{ + int pkey; + int ret; + void *ptr; + void *ptr2; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_two_continues_fixed_address_protect_second_with_pkey( + enforce, size, &pkey, &ptr, &ptr2); + + // disable write through pkey. + pkey_write_deny(pkey); + + // modify the first addr is allowed. + ret = sys_mprotect(ptr, size, PROT_READ | PROT_WRITE | PROT_EXEC); + assert(!ret); + + // modify the second mmap is protected by pkey. + ret = sys_mprotect(ptr2, size, PROT_READ | PROT_WRITE | PROT_EXEC); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + // mprotect both addresses (merged). + ret = sys_mprotect_pkey(ptr, size * 2, + PROT_READ | PROT_WRITE | PROT_EXEC, pkey); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + ret = sys_mprotect(ptr, size * 2, PROT_READ | PROT_WRITE | PROT_EXEC); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + ret = sys_mprotect_pkey(ptr, size * 2, PROT_READ, pkey); + assert(!ret); + + ret = sys_mprotect(ptr, size * 2, PROT_READ); + assert(!ret); + + clean_two_address_with_pkey(size, pkey, ptr, ptr2); +} + +void setup_4pages_fixed_protect_second_page(bool enforce, int size, + int *pkeyOut, void **ptrOut, + void **ptr2Out, void **ptr3Out) +{ + int pkey; + int ret; + void *ptr; + + pkey = pkey_alloc_with_check(enforce); + + // allocate 4 pages. + ptr = mmap(addr1, size * 4, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + assert(ptr == addr1); + + // assign pkey to the second address. + ret = sys_mprotect_pkey(addr2, size, PROT_READ | PROT_WRITE | PROT_EXEC, + pkey); + assert(!ret); + + *pkeyOut = pkey; + *ptrOut = ptr; + *ptr2Out = addr2; + *ptr3Out = addr3; +} + +// mmap one address with 4 pages. +// assign PKEY to the second page only. +// mprotect on the first page is allowed. +// mprotect on the second page is protected in enforce mode. +// mprotect on memory range that includes the second pages is protected. +void test_mprotect_vma_middle_addr(bool enforce) +{ + int pkey; + int ret; + void *ptr, *ptr2, *ptr3; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_4pages_fixed_protect_second_page(enforce, size, &pkey, &ptr, + &ptr2, &ptr3); + + // disable write through pkey. + pkey_write_deny(pkey); + + // modify to the first page is allowed. + ret = sys_mprotect(ptr, size, PROT_READ | PROT_WRITE | PROT_EXEC); + assert(!ret); + + // modify to the third page is allowed. + ret = sys_mprotect(ptr3, size, PROT_READ | PROT_WRITE | PROT_EXEC); + assert(!ret); + + // modify to the second page is protected by pkey. + ret = sys_mprotect(ptr2, size, PROT_READ | PROT_WRITE | PROT_EXEC); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + // modify to memory range that includes the second page is protected. + ret = sys_mprotect_pkey(ptr, size * 4, + PROT_READ | PROT_WRITE | PROT_EXEC, pkey); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + ret = sys_mprotect(ptr, size * 4, PROT_READ | PROT_WRITE | PROT_EXEC); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + ret = sys_mprotect(addr2, size, PROT_READ | PROT_WRITE | PROT_EXEC); + assert(!ret); + + ret = sys_mprotect_pkey(ptr, size * 4, + PROT_READ | PROT_WRITE | PROT_EXEC, pkey); + assert(!ret); + + clean_single_address_with_pkey(pkey, ptr, size * 4); +} + +// mmap one address with 4 pages. +// assign PKEY to the second page only. +// mprotect on the second page, but size is unaligned. +void test_mprotect_unaligned(bool enforce) +{ + int pkey; + int ret; + void *ptr, *ptr2, *ptr3; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_4pages_fixed_protect_second_page(enforce, size, &pkey, &ptr, + &ptr2, &ptr3); + + // disable write through pkey. + pkey_write_deny(pkey); + + // modify to the first page is allowed. + ret = sys_mprotect(ptr, size, PROT_READ | PROT_WRITE | PROT_EXEC); + assert(!ret); + + // modify to the second page is protected by pkey. + ret = sys_mprotect(ptr2, size - 1, PROT_READ | PROT_WRITE | PROT_EXEC); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + ret = sys_mprotect(addr2, size - 1, PROT_READ | PROT_WRITE | PROT_EXEC); + assert(!ret); + + clean_single_address_with_pkey(pkey, ptr, size * 4); +} + +// mmap one address with 4 pages. +// assign PKEY to the second page only. +// mprotect on the second page, but size is unaligned. +void test_mprotect_unaligned2(bool enforce) +{ + int pkey; + int ret; + void *ptr, *ptr2, *ptr3; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_4pages_fixed_protect_second_page(enforce, size, &pkey, &ptr, + &ptr2, &ptr3); + + // disable write through pkey. + pkey_write_deny(pkey); + + // modify to the first page is allowed. + ret = sys_mprotect(ptr, size, PROT_READ | PROT_WRITE | PROT_EXEC); + assert(!ret); + + // modify to the second page is protected by pkey. + ret = sys_mprotect(ptr2, size + 1, PROT_READ | PROT_WRITE | PROT_EXEC); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + ret = sys_mprotect(addr2, size + 1, PROT_READ | PROT_WRITE | PROT_EXEC); + assert(!ret); + + clean_single_address_with_pkey(pkey, ptr, size * 4); +} + +void setup_address_with_gap_two_pkeys(bool enforce, int size, int *pkeyOut, + int *pkey2Out, void **ptrOut, + void **ptr2Out) +{ + int pkey, pkey2; + void *ptr, *ptr2; + int ret; + + pkey = pkey_alloc_with_check(enforce); + pkey2 = pkey_alloc_with_check(enforce); + + ptr = mmap(addr1, size, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + assert(ptr == (void *)addr1); + + ptr2 = mmap(addr3, size, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + assert(ptr2 == (void *)addr3); + + // assign pkey to the memory. + ret = sys_mprotect_pkey((void *)ptr, size, PROT_READ, pkey); + assert(!ret); + + // assign pkey to the memory. + ret = sys_mprotect_pkey((void *)ptr2, size, PROT_READ, pkey2); + assert(!ret); + + *pkeyOut = pkey; + *ptrOut = ptr; + + *pkey2Out = pkey2; + *ptr2Out = ptr2; +} + +void clean_address_with_pag_two_pkeys(int pkey, void *ptr, int pkey2, + void *ptr2, int size) +{ + int ret; + + ret = munmap(ptr, size); + assert(!ret); + + ret = sys_pkey_free(pkey); + assert(ret == 0); + + ret = munmap(ptr2, size); + assert(!ret); + + ret = sys_pkey_free(pkey2); + assert(ret == 0); +} + +// mmap two addresses, with a page gap between two. +// assign pkeys on both address. +// disable access to the second address. +// mprotect from start of address1 to the end of address 2, +// because there is a gap in the memory range, mprotect will fail. +void test_mprotect_gapped_address_with_two_pkeys(bool enforce) +{ + int pkey, pkey2; + int ret; + void *ptr, *ptr2; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_address_with_gap_two_pkeys(enforce, size, &pkey, &pkey2, &ptr, + &ptr2); + + // disable write access. + pkey_write_deny(pkey2); + + ret = sys_mprotect_pkey(ptr, size * 3, PROT_READ | PROT_WRITE, pkey); + assert(ret < 0); + + ret = sys_mprotect(ptr, size * 3, PROT_READ | PROT_WRITE); + assert(ret < 0); + + pkey_write_allow(pkey2); + + ret = sys_mprotect_pkey(ptr, size * 3, PROT_READ, pkey); + assert(ret < 0); + + ret = sys_mprotect(ptr, size * 3, PROT_READ); + assert(ret < 0); + + clean_address_with_pag_two_pkeys(pkey, ptr, pkey2, ptr2, size); +} + +struct thread_info { + int pkey; + void *addr; + int size; + bool enforce; +}; + +void *thread_mprotect(void *arg) +{ + struct thread_info *tinfo = arg; + void *ptr = tinfo->addr; + int size = tinfo->size; + bool enforce = tinfo->enforce; + int pkey = tinfo->pkey; + int ret; + + // disable write access. + pkey_write_deny(pkey); + ret = sys_mprotect_pkey(ptr, size, PROT_READ | PROT_WRITE, pkey); + + if (enforce) + assert(ret < 0); + else + assert(!ret); + + ret = sys_mprotect(ptr, size, PROT_READ | PROT_WRITE); + if (enforce) + assert(ret < 0); + else + assert(ret == 0); + + pkey_write_allow(pkey); + + ret = sys_mprotect_pkey(ptr, size, PROT_READ, pkey); + assert(!ret); + + ret = sys_mprotect(ptr, size, PROT_READ); + assert(ret == 0); + return NULL; +} + +// mmap one address. +// assign pkey on the address. +// in child thread, mprotect is denied when no-writeable PKRU in enforce mode. +void test_mprotect_child_thread(bool enforce) +{ + int pkey; + int ret; + void *ptr; + int size = PAGE_SIZE; + pthread_t thread; + struct thread_info tinfo; + + LOG_TEST_ENTER(enforce); + + setup_single_fixed_address_with_pkey(enforce, size, &pkey, &ptr); + tinfo.size = size; + tinfo.addr = ptr; + tinfo.enforce = enforce; + tinfo.pkey = pkey; + + ret = pthread_create(&thread, NULL, thread_mprotect, (void *)&tinfo); + assert(ret == 0); + pthread_join(thread, NULL); + + clean_single_address_with_pkey(pkey, ptr, size); +} + +void test_enforce_api(void) +{ + for (int i = 0; i < 2; i++) { + bool enforce = (i == 1); + + test_pkey_alloc(enforce); + + test_mprotect_single_address(enforce); + test_mprotect_two_address_merge(enforce); + test_mprotect_two_address_deny_second(enforce); + test_mprotect_vma_middle_addr(enforce); + test_mprotect_unaligned(enforce); + test_mprotect_unaligned2(enforce); + test_mprotect_child_thread(enforce); + test_mprotect_gapped_address_with_two_pkeys(enforce); + } +} + +int main(void) +{ + int pkeys_supported = is_pkeys_supported(); + + printf("pid: %d\n", getpid()); + printf("has pkeys: %d\n", pkeys_supported); + if (!pkeys_supported) { + printf("PKEY not supported, skip the test.\n"); + exit(0); + } + + test_enforce_api(); + printf("done (all tests OK)\n"); + return 0; +} +#else /* arch */ +int main(void) +{ + printf("SKIP: not supported arch\n"); + return 0; +} +#endif /* arch */

From: Jeff Xu jeffxu@google.com

Add selftest for pkey_enforce_api for mprotect

Signed-off-by: Jeff Xujeffxu@google.com --- tools/testing/selftests/mm/pkey_enforce_api.c | 437 ++++++++++++++++++ 1 file changed, 437 insertions(+)

diff --git a/tools/testing/selftests/mm/pkey_enforce_api.c b/tools/testing/selftests/mm/pkey_enforce_api.c index 23663c89bc9c..92aa29248e1f 100644 --- a/tools/testing/selftests/mm/pkey_enforce_api.c +++ b/tools/testing/selftests/mm/pkey_enforce_api.c @@ -833,6 +833,429 @@ void test_mprotect_child_thread(bool enforce) clean_single_address_with_pkey(pkey, ptr, size); }

+// mmap one address with one page. +// assign PKEY to the address. +// munmap on the address is protected. +void test_munmap_single_address(bool enforce) +{ + int pkey; + int ret; + void *ptr; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_single_address_with_pkey(enforce, size, &pkey, &ptr); + + // disable write access. + pkey_write_deny(pkey); + + ret = munmap(ptr, size); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + if (enforce) { + ret = munmap(ptr, size); + assert(!ret); + } + + clean_single_address_with_pkey(pkey, ptr, size); +} + +// mmap two address (continuous two pages). +// assign PKEY to them with one mprotect_pkey call (merged address). +// munmap two address in one call (merged address). +void test_munmap_two_address_merge(bool enforce) +{ + int pkey; + int ret; + void *ptr; + void *ptr2; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_two_continues_fixed_address_with_pkey(enforce, size, &pkey, &ptr, + &ptr2); + + // disable write. + pkey_write_deny(pkey); + + // munmap on both addresses with one call (merged). + ret = munmap(ptr, size * 2); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + if (enforce) { + ret = munmap(ptr, size * 2); + assert(!ret); + } + + ret = sys_pkey_free(pkey); + assert(ret == 0); +} + +// mmap two address (continuous two pages). +// assign PKEY to the second address. +// munmap on the second address is protected. +void test_munmap_two_address_deny_second(bool enforce) +{ + int pkey; + int ret; + void *ptr; + void *ptr2; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_two_continues_fixed_address_protect_second_with_pkey( + enforce, size, &pkey, &ptr, &ptr2); + + // disable write through pkey. + pkey_write_deny(pkey); + + ret = munmap(ptr2, size); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + ret = munmap(ptr, size); + assert(!ret); + + pkey_write_allow(pkey); + + if (enforce) { + ret = munmap(ptr2, size); + assert(!ret); + } + + ret = sys_pkey_free(pkey); + assert(ret == 0); +} + +// mmap two address (continuous two pages). +// assign PKEY to the second address. +// munmap on the range that includes the second address. +void test_munmap_two_address_deny_range(bool enforce) +{ + int pkey; + int ret; + void *ptr; + void *ptr2; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_two_continues_fixed_address_protect_second_with_pkey( + enforce, size, &pkey, &ptr, &ptr2); + + // disable write through pkey. + pkey_write_deny(pkey); + + ret = munmap(ptr, size * 2); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + if (enforce) { + ret = munmap(ptr, size * 2); + assert(!ret); + } + + ret = sys_pkey_free(pkey); + assert(ret == 0); +} + +// mmap one address with 4 pages. +// assign PKEY to the second page only. +// munmap on memory range that includes the second pages is protected. +void test_munmap_vma_middle_addr(bool enforce) +{ + int pkey; + int ret; + void *ptr, *ptr2, *ptr3; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_4pages_fixed_protect_second_page(enforce, size, &pkey, &ptr, + &ptr2, &ptr3); + + // disable write through pkey. + pkey_write_deny(pkey); + + // munmap support merge, we are going to make sure we don't regress. + ret = munmap(addr1, size * 4); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + if (enforce) { + ret = munmap(ptr, size * 4); + assert(!ret); + } + + ret = sys_pkey_free(pkey); + assert(ret == 0); +} + +// mmap one address with 4 pages. +// assign PKEY to the second page only. +// munmap from 2nd page. +void test_munmap_shrink(bool enforce) +{ + int pkey; + int ret; + void *ptr, *ptr2, *ptr3; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_4pages_fixed_protect_second_page(enforce, size, &pkey, &ptr, + &ptr2, &ptr3); + + // disable write through pkey. + pkey_write_deny(pkey); + + // munmap support merge, we are going to make sure we don't regress. + ret = munmap(ptr2, size * 3); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + if (enforce) { + ret = munmap(ptr2, size * 3); + assert(!ret); + } + + ret = munmap(ptr, size); + assert(!ret); + + ret = sys_pkey_free(pkey); + assert(ret == 0); +} + +// mmap one address with 4 pages. +// assign PKEY to the second page only. +// munmap from 2nd page but size is less than one page +void test_munmap_unaligned(bool enforce) +{ + int pkey; + int ret; + void *ptr, *ptr2, *ptr3; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_4pages_fixed_protect_second_page(enforce, size, &pkey, &ptr, + &ptr2, &ptr3); + + // disable write through pkey. + pkey_write_deny(pkey); + + // munmap support merge, we are going to make sure we don't regress. + ret = munmap(ptr2, size - 1); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + if (enforce) { + ret = munmap(ptr2, size - 1); + assert(!ret); + } + + ret = munmap(ptr, size * 4); + assert(!ret); + + ret = sys_pkey_free(pkey); + assert(ret == 0); +} + +// mmap one address with 4 pages. +// assign PKEY to the second page only. +// munmap from 2nd page but size is less than one page +void test_munmap_unaligned2(bool enforce) +{ + int pkey; + int ret; + void *ptr, *ptr2, *ptr3; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_4pages_fixed_protect_second_page(enforce, size, &pkey, &ptr, + &ptr2, &ptr3); + + // disable write through pkey. + pkey_write_deny(pkey); + + // munmap support merge, we are going to make sure we don't regress. + ret = munmap(ptr2, size + 1); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + if (enforce) { + ret = munmap(ptr2, size + 1); + assert(!ret); + } + + ret = munmap(ptr, size * 4); + assert(!ret); + + ret = sys_pkey_free(pkey); + assert(ret == 0); +} + +// mmap one address with one page. +// assign PKEY to the address. +// munmap on the address but with size of 4 pages(should OK). +void test_munmap_outbound_addr(bool enforce) +{ + int pkey; + int ret; + void *ptr; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_single_fixed_address_with_pkey(enforce, size, &pkey, &ptr); + + // disable write through pkey. + pkey_write_deny(pkey); + + // Interesting enough, this is allowed, even the other 3 pages are not allocated. + ret = munmap(addr1, size * 4); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey); + + if (enforce) { + ret = munmap(addr1, size * 4); + assert(!ret); + } + + clean_single_address_with_pkey(pkey, ptr, size); +} +// mmap two addresses, with a page gap between two. +// assign pkeys on both address. +// disable access to the second address. +// munmap from start of address1 to the end of address 2, +// because there is a gap in the memory range, mprotect will fail. +void test_munmap_gapped_address_with_two_pkeys(bool enforce) +{ + int pkey, pkey2; + int ret; + void *ptr, *ptr2; + int size = PAGE_SIZE; + + LOG_TEST_ENTER(enforce); + + setup_address_with_gap_two_pkeys(enforce, size, &pkey, &pkey2, &ptr, + &ptr2); + + // disable write access. + pkey_write_deny(pkey2); + + // Interesting enough, this is allowed, even there is a gap beween address 1 and 2. + ret = munmap(addr1, size * 3); + if (enforce) + assert(ret < 0); + else + assert(!ret); + + pkey_write_allow(pkey2); + if (enforce) { + ret = munmap(addr1, size * 3); + assert(!ret); + } +} + +// use write-deny pkey and see if program can exit properly. +// This is manual test, run it at end if needed. +void test_exit_munmap_disable_write(void) +{ + int pkey; + int ret; + void *ptr; + int size = PAGE_SIZE; + + pkey = sys_pkey_alloc(PKEY_ENFORCE_API, 0); + assert(pkey > 0); + + // allocate 1 page. + ptr = mmap(addr1, size, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + assert(ptr == addr1); + + // assign pkey to the first address. + ret = sys_mprotect_pkey(ptr, size, PROT_READ | PROT_WRITE | PROT_EXEC, + pkey); + assert(!ret); + + // disable write through pkey. + pkey_write_deny(pkey); + + ret = munmap(ptr, size); + assert(ret < 0); +} + +// use disable-all pkey and see if program can exit properly. +// This is manual test, run it at end if needed. +void test_exit_munmap_disable_all(void) +{ + int pkey; + int ret; + void *ptr; + int size = PAGE_SIZE; + + pkey = sys_pkey_alloc(PKEY_ENFORCE_API, 0); + assert(pkey > 0); + + // allocate 1 page. + ptr = mmap(addr2, size, PROT_READ, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + assert(ptr == addr2); + + // assign pkey to the first address. + ret = sys_mprotect_pkey(ptr, size, PROT_READ | PROT_WRITE | PROT_EXEC, + pkey); + assert(!ret); + + // disable write through pkey. + pkey_access_deny(pkey); + + ret = munmap(addr1, size); + assert(ret < 0); +} + void test_enforce_api(void) { for (int i = 0; i < 2; i++) { @@ -848,7 +1271,21 @@ void test_enforce_api(void) test_mprotect_unaligned2(enforce); test_mprotect_child_thread(enforce); test_mprotect_gapped_address_with_two_pkeys(enforce); + + test_munmap_single_address(enforce); + test_munmap_two_address_merge(enforce); + test_munmap_two_address_deny_second(enforce); + test_munmap_two_address_deny_range(enforce); + test_munmap_vma_middle_addr(enforce); + test_munmap_outbound_addr(enforce); + test_munmap_shrink(enforce); + test_munmap_unaligned(enforce); + test_munmap_unaligned2(enforce); + test_munmap_gapped_address_with_two_pkeys(enforce); } + + test_exit_munmap_disable_write(); + test_exit_munmap_disable_all(); }

int main(void)