From: Milan Broz Date: Mon, 20 Feb 2023 16:45:36 +0100 Subject: Try to avoid OOM killer on low-memory systems without swap. Benchmark for memory-hard KDF is tricky, seems that relying on maximum half of physical memory is not enough. Let's allow only free physical available space if there is no swap. This should not cause changes on normal systems, at least. Origin: https://gitlab.com/cryptsetup/cryptsetup/-/commit/899bad8c06957a94a198d1eaa293ed8db205f1de Bug: https://gitlab.com/cryptsetup/cryptsetup/-/issues/802 Bug-Debian: https://bugs.debian.org/1028250 --- lib/internal.h | 2 ++ lib/utils.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ lib/utils_pbkdf.c | 11 ++++++++++- tests/api-test-2.c | 12 ++++++++---- 4 files changed, 67 insertions(+), 5 deletions(-) diff --git a/lib/internal.h b/lib/internal.h index b5cb4e3..98095fa 100644 --- a/lib/internal.h +++ b/lib/internal.h @@ -168,6 +168,8 @@ int crypt_uuid_cmp(const char *dm_uuid, const char *hdr_uuid); size_t crypt_getpagesize(void); unsigned crypt_cpusonline(void); uint64_t crypt_getphysmemory_kb(void); +uint64_t crypt_getphysmemoryfree_kb(void); +bool crypt_swapavailable(void); int init_crypto(struct crypt_device *ctx); diff --git a/lib/utils.c b/lib/utils.c index bfcf60d..e9d5b5b 100644 --- a/lib/utils.c +++ b/lib/utils.c @@ -59,6 +59,53 @@ uint64_t crypt_getphysmemory_kb(void) return phys_memory_kb; } +uint64_t crypt_getphysmemoryfree_kb(void) +{ + long pagesize, phys_pages; + uint64_t phys_memoryfree_kb; + + pagesize = sysconf(_SC_PAGESIZE); + phys_pages = sysconf(_SC_AVPHYS_PAGES); + + if (pagesize < 0 || phys_pages < 0) + return 0; + + phys_memoryfree_kb = pagesize / 1024; + phys_memoryfree_kb *= phys_pages; + + return phys_memoryfree_kb; +} + +bool crypt_swapavailable(void) +{ + int fd; + ssize_t size; + char buf[4096], *p; + uint64_t total; + + if ((fd = open("/proc/meminfo", O_RDONLY)) < 0) + return true; + + size = read(fd, buf, sizeof(buf)); + close(fd); + if (size < 1) + return true; + + if (size < (ssize_t)sizeof(buf)) + buf[size] = 0; + else + buf[sizeof(buf) - 1] = 0; + + p = strstr(buf, "SwapTotal:"); + if (!p) + return true; + + if (sscanf(p, "SwapTotal: %" PRIu64 " kB", &total) != 1) + return true; + + return total > 0; +} + void crypt_process_priority(struct crypt_device *cd, int *priority, bool raise) { int _priority, new_priority; diff --git a/lib/utils_pbkdf.c b/lib/utils_pbkdf.c index 4d7e18d..d8f41c7 100644 --- a/lib/utils_pbkdf.c +++ b/lib/utils_pbkdf.c @@ -63,7 +63,7 @@ const struct crypt_pbkdf_type *crypt_get_pbkdf_type_params(const char *pbkdf_typ static uint32_t adjusted_phys_memory(void) { - uint64_t memory_kb = crypt_getphysmemory_kb(); + uint64_t free_kb, memory_kb = crypt_getphysmemory_kb(); /* Ignore bogus value */ if (memory_kb < (128 * 1024) || memory_kb > UINT32_MAX) @@ -75,6 +75,15 @@ static uint32_t adjusted_phys_memory(void) */ memory_kb /= 2; + /* + * Never use more that available free space on system without swap. + */ + if (!crypt_swapavailable()) { + free_kb = crypt_getphysmemoryfree_kb(); + if (free_kb > (64 * 1024) && free_kb < memory_kb) + return free_kb; + } + return memory_kb; } diff --git a/tests/api-test-2.c b/tests/api-test-2.c index 824ae65..923165c 100644 --- a/tests/api-test-2.c +++ b/tests/api-test-2.c @@ -2802,7 +2802,8 @@ static void Pbkdf(void) OK_(strcmp(pbkdf->type, default_luks2_pbkdf)); OK_(strcmp(pbkdf->hash, default_luks1_hash)); EQ_(pbkdf->time_ms, default_luks2_iter_time); - EQ_(pbkdf->max_memory_kb, adjusted_pbkdf_memory()); + GE_(pbkdf->max_memory_kb, 64 * 1024); + GE_(adjusted_pbkdf_memory(), pbkdf->max_memory_kb); EQ_(pbkdf->parallel_threads, _min(cpus_online(), default_luks2_parallel_threads)); // set and verify argon2 type OK_(crypt_set_pbkdf_type(cd, &argon2)); @@ -2827,7 +2828,8 @@ static void Pbkdf(void) OK_(strcmp(pbkdf->type, default_luks2_pbkdf)); OK_(strcmp(pbkdf->hash, default_luks1_hash)); EQ_(pbkdf->time_ms, default_luks2_iter_time); - EQ_(pbkdf->max_memory_kb, adjusted_pbkdf_memory()); + GE_(pbkdf->max_memory_kb, 64 * 1024); + GE_(adjusted_pbkdf_memory(), pbkdf->max_memory_kb); EQ_(pbkdf->parallel_threads, _min(cpus_online(), default_luks2_parallel_threads)); // try to pass illegal values argon2.parallel_threads = 0; @@ -2858,14 +2860,16 @@ static void Pbkdf(void) OK_(strcmp(pbkdf->type, default_luks2_pbkdf)); OK_(strcmp(pbkdf->hash, default_luks1_hash)); EQ_(pbkdf->time_ms, default_luks2_iter_time); - EQ_(pbkdf->max_memory_kb, adjusted_pbkdf_memory()); + GE_(pbkdf->max_memory_kb, 64 * 1024); + GE_(adjusted_pbkdf_memory(), pbkdf->max_memory_kb); EQ_(pbkdf->parallel_threads, _min(cpus_online(), default_luks2_parallel_threads)); crypt_set_iteration_time(cd, 1); OK_(crypt_load(cd, CRYPT_LUKS, NULL)); OK_(strcmp(pbkdf->type, default_luks2_pbkdf)); OK_(strcmp(pbkdf->hash, default_luks1_hash)); EQ_(pbkdf->time_ms, 1); - EQ_(pbkdf->max_memory_kb, adjusted_pbkdf_memory()); + GE_(pbkdf->max_memory_kb, 64 * 1024); + GE_(adjusted_pbkdf_memory(), pbkdf->max_memory_kb); EQ_(pbkdf->parallel_threads, _min(cpus_online(), default_luks2_parallel_threads)); CRYPT_FREE(cd);