From d0f5da9dd7d6d49af8fab1e3063c82bf74b811a9 Mon Sep 17 00:00:00 2001 From: Alexander Mikhalitsyn Date: Sun, 20 Apr 2025 20:20:20 +0200 Subject: [PATCH] test/zdtm/static/maps12: add madv guards test Test for madvise(MADV_GUARD_INSTALL). Signed-off-by: Alexander Mikhalitsyn --- test/zdtm/static/Makefile | 1 + test/zdtm/static/maps12.c | 350 +++++++++++++++++++++++++++++++++++ test/zdtm/static/maps12.desc | 1 + 3 files changed, 352 insertions(+) create mode 100644 test/zdtm/static/maps12.c create mode 100644 test/zdtm/static/maps12.desc diff --git a/test/zdtm/static/Makefile b/test/zdtm/static/Makefile index ab69f389e..e73f964be 100644 --- a/test/zdtm/static/Makefile +++ b/test/zdtm/static/Makefile @@ -315,6 +315,7 @@ TST_FILE = \ write_read02 \ write_read10 \ maps00 \ + maps12 \ link10 \ file_attr \ deleted_unix_sock \ diff --git a/test/zdtm/static/maps12.c b/test/zdtm/static/maps12.c new file mode 100644 index 000000000..b645595be --- /dev/null +++ b/test/zdtm/static/maps12.c @@ -0,0 +1,350 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "zdtmtst.h" + +const char *test_doc = "Test madvise(MADV_GUARD_INSTALL)"; +const char *test_author = "Alexander Mikhalitsyn "; +/* some parts of code were taken from Linux kernel's kselftest guard-pages.c + written by Lorenzo Stoakes */ + +char *filename; +int fd; +TEST_OPTION(filename, string, "file name", 1); + +#ifndef MADV_GUARD_INSTALL +#define MADV_GUARD_INSTALL 102 +#endif + +uint8_t *map_base; + +struct { + unsigned int pages_num; + bool filemap; +} vmas[] = { + { 2, false }, + { 2, false }, + { 2, false }, + { 2, true }, + { 2, true }, + { 2, true }, +}; + +struct { + bool guarded; + bool wipeonfork; +} pages[] = { + { false, false }, /* vmas[0] */ + { true, false }, + { true, false }, /* vmas[1] */ + { false, false }, + { false, false }, /* vmas[2] */ + { true, true }, + { true, false }, /* vmas[3] */ + { false, false }, + { true, false }, /* vmas[4] */ + { true, false }, + { false, false }, /* vmas[5] */ + { true, false }, +}; + +static volatile sig_atomic_t signal_jump_set; +static sigjmp_buf signal_jmp_buf; + +static void handle_sigsegv(int signo) +{ + if (!signal_jump_set) + return; + + siglongjmp(signal_jmp_buf, 1); +} + +static bool try_write_to_addr(uint8_t *ptr) +{ + bool failed; + + /* Tell signal handler to jump back here on fatal signal. */ + signal_jump_set = true; + /* If a fatal signal arose, we will jump back here and failed is set. */ + failed = sigsetjmp(signal_jmp_buf, 1) != 0; + + if (!failed) + *ptr = 'x'; + + signal_jump_set = false; + return !failed; +} + +static int setup_sigsegv_handler(void) +{ + uint8_t write_me; + + if (signal(SIGSEGV, handle_sigsegv) == SIG_ERR) { + pr_perror("setting SIGSEGV handler failed"); + return 1; + } + + /* ensure that try_write_to_addr() works properly */ + if (!try_write_to_addr(&write_me)) { + pr_err("Failed to write at valid addr. Buggy try_write_to_addr()?\n"); + return 1; + } + + if (try_write_to_addr(NULL)) { + pr_err("Failed to detect an invalid write. Buggy try_write_to_addr()?\n"); + return 1; + } + + return 0; +} + +static inline void *mmap_pages(void *addr_hint, unsigned int count, bool filemap) +{ + char *map; + + map = mmap(addr_hint, count * PAGE_SIZE, PROT_WRITE | PROT_READ, + MAP_PRIVATE | (filemap ? 0 : MAP_ANONYMOUS) | (addr_hint ? MAP_FIXED : 0), + filemap ? fd : -1, filemap ? ((off_t)addr_hint - (off_t)map_base) : 0); + if (map == MAP_FAILED || (addr_hint && (map != addr_hint))) + return MAP_FAILED; + + return map; +} + +static int __check_guards(const char *when, bool in_child) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(pages); i++) { + /* + * Skip pages that were never guarded, and also those + * that were, but have MADV_WIPEONFORK which means that + * guards were removed on fork. + */ + if (!pages[i].guarded || (in_child && pages[i].wipeonfork)) + continue; + + if (try_write_to_addr(&map_base[i * PAGE_SIZE])) { + pr_err("successful write to a guarded area %d %s C/R\n", + i, when); + return 1; + } + } + + return 0; +} + +static int check_guards(const char *when) +{ + int status; + pid_t pid; + + /* + * First of all, check that guards are on their places + * in a main test process. + */ + if (__check_guards(when, false)) { + return 1; + } + + /* + * Now, check that guards are on their places + * after fork(). This allows to ensure that + * combo MADV_WIPEONFORK + MADV_GUARD_INSTALL + * is restored properly too. + */ + + pid = test_fork(); + if (pid < 0) { + pr_perror("check_guards: fork failed"); + return 1; + } + + if (pid == 0) { + if (__check_guards(when, true)) { + pr_err("check_guards(\"%s\") failed in child\n", when); + exit(1); + } + + exit(0); + } + + if (waitpid(pid, &status, 0) != pid) { + pr_perror("check_guards: waitpid"); + return 1; + } + + if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { + pr_err("check_guards: process didn't exit cleanly: status=%d\n", status); + return 1; + } + + return 0; +} + +static void gen_pages_data(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(pages); i++) { + uint32_t crc; + + if (pages[i].guarded) + continue; + + crc = ~0; + datagen(&map_base[i * PAGE_SIZE], PAGE_SIZE, &crc); + } +} + +static int set_pages_madvs(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(pages); i++) { + if (pages[i].guarded) { + if (madvise(&map_base[i * PAGE_SIZE], PAGE_SIZE, + MADV_GUARD_INSTALL)) { + pr_perror("MADV_GUARD_INSTALL failed on page %d", i); + return 1; + } + } + + if (pages[i].wipeonfork) { + if (madvise(&map_base[i * PAGE_SIZE], PAGE_SIZE, + MADV_WIPEONFORK)) { + pr_perror("MADV_WIPEONFORK failed on page %d", i); + return 1; + } + } + } + + return 0; +} + +static int check_pages_data(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(pages); i++) { + uint32_t crc; + + if (pages[i].guarded) + continue; + + crc = ~0; + if (datachk(&map_base[i * PAGE_SIZE], PAGE_SIZE, &crc)) { + pr_err("Page %d is corrupted\n", i); + return 1; + } + } + + return 0; +} + +static int prepare_vmas(void) +{ + char *map; + int i, shift; + + shift = 0; + for (i = 0; i < ARRAY_SIZE(vmas); i++) { + map = mmap_pages(&map_base[shift * PAGE_SIZE], + vmas[i].pages_num, vmas[i].filemap); + if (map == MAP_FAILED) { + pr_err("mmap of [%d,%d] pages failed\n", + shift, shift + vmas[i].pages_num); + return 1; + } + + shift += vmas[i].pages_num; + } + + if (shift != ARRAY_SIZE(pages)) { + pr_err("Different number of pages in vmas and pages arrays.\n"); + return 1; + } + + return 0; +} + +int main(int argc, char **argv) +{ + unsigned int pages_num = ARRAY_SIZE(pages); + + test_init(argc, argv); + + fd = open(filename, O_TRUNC | O_CREAT | O_RDWR, 0600); + if (fd < 0) { + pr_perror("Unable to create a test file"); + return -1; + } + + if (ftruncate(fd, pages_num * PAGE_SIZE)) { + pr_perror("Unable to ftruncate a test file"); + return -1; + } + + if (setup_sigsegv_handler()) { + pr_err("setup_sigsegv_handler() failed\n"); + return 1; + } + + /* let's find a large enough area in address space */ + map_base = mmap_pages(NULL, pages_num, false); + if (map_base == MAP_FAILED) { + pr_err("mmap of %d pages failed\n", pages_num); + return 1; + } + + /* + * Now we know that we have a free vm address space area + * [map_base, map_base + pages_num * PAGE_SIZE). + * We can use (map_base) as a hint for our further mmaps. + */ + if (prepare_vmas()) { + pr_err("prepare_vmas() failed\n"); + return 1; + } + + /* fill non-guarded pages with data and preserve checksums */ + gen_pages_data(); + + if (set_pages_madvs()) { + pr_err("set_pages_madvs() failed\n"); + return 1; + } + + /* ensure that madvise(MADV_GUARD_INSTALL) works like expected */ + if (check_guards("before")) { + pr_err("check_guards(\"before\") failed\n"); + return 1; + } + + test_daemon(); + test_waitsig(); + + /* ensure that guards are at their places */ + if (check_guards("after")) { + fail("check_guards(\"after\") failed"); + return 1; + } + + /* check that non-guarded pages still contain original data */ + if (check_pages_data()) { + fail("check_pages_data() failed"); + return 1; + } + + pass(); + munmap(map_base, pages_num * PAGE_SIZE); + close(fd); + return 0; +} diff --git a/test/zdtm/static/maps12.desc b/test/zdtm/static/maps12.desc new file mode 100644 index 000000000..3f7627ff3 --- /dev/null +++ b/test/zdtm/static/maps12.desc @@ -0,0 +1 @@ +{'flavor': 'h', 'feature': 'pagemap_scan_guard_pages'}