From aa25270cb22f5f7ca2b18c288d4e15bbc6eb239e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= Date: Fri, 25 Sep 2020 17:16:06 +0200 Subject: [PATCH] sysusers: look at login.defs when setting the default range to allocate users Also, even if login.defs are not present, don't start allocating at 1, but at SYSTEM_UID_MIN. Fixes #9769. The test is adjusted. Actually, it was busted before, because sysusers would never use SYSTEM_GID_MIN, so if SYSTEM_GID_MIN was different than SYSTEM_UID_MIN, the tests would fail. On all "normal" systems the two are equal, so we didn't notice. Since sysusers now always uses the minimum of the two, we only need to substitute one value. --- meson.build | 1 + src/shared/user-record.c | 13 +++-- src/shared/user-record.h | 1 + src/sysusers/sysusers.c | 22 ++++++-- src/test/test-user-record.c | 48 ++++++++++++++++++ test/test-sysusers.sh.in | 59 ++++++++++++++++++++-- test/test-sysusers/test-10.expected-group | 2 +- test/test-sysusers/test-10.expected-passwd | 2 +- test/test-sysusers/test-13.expected-group | 2 +- test/test-sysusers/test-13.expected-passwd | 2 +- test/test-sysusers/test-14.expected-passwd | 2 +- test/test-sysusers/test-2.expected-group | 2 +- test/test-sysusers/test-2.expected-passwd | 2 +- test/test-sysusers/test-2.input | 2 +- test/test-sysusers/test-6.expected-group | 2 +- test/test-sysusers/test-6.expected-passwd | 2 +- test/test-sysusers/test-8.expected-passwd | 2 +- test/test-sysusers/test-9.expected-passwd | 2 +- 18 files changed, 143 insertions(+), 25 deletions(-) diff --git a/meson.build b/meson.build index 3bec86db81..23cf3e528a 100644 --- a/meson.build +++ b/meson.build @@ -1467,6 +1467,7 @@ foreach term : ['analyze', have = get_option(term) name = 'ENABLE_' + term.underscorify().to_upper() conf.set10(name, have) + substs.set10(name, have) endforeach enable_sysusers = conf.get('ENABLE_SYSUSERS') == 1 diff --git a/src/shared/user-record.c b/src/shared/user-record.c index 3ba78d455f..7e7b28eb55 100644 --- a/src/shared/user-record.c +++ b/src/shared/user-record.c @@ -37,21 +37,24 @@ static int parse_alloc_uid(const char *path, const char *name, const char *t, ui *ret_uid = uid; return 0; } +#endif -static int read_login_defs(UGIDAllocationRange *ret_defs, const char *path) { - _cleanup_fclose_ FILE *f = NULL; +int read_login_defs(UGIDAllocationRange *ret_defs, const char *path, const char *root) { UGIDAllocationRange defs = { .system_alloc_uid_min = SYSTEM_ALLOC_UID_MIN, .system_uid_max = SYSTEM_UID_MAX, .system_alloc_gid_min = SYSTEM_ALLOC_GID_MIN, .system_gid_max = SYSTEM_GID_MAX, }; + +#if ENABLE_COMPAT_MUTABLE_UID_BOUNDARIES + _cleanup_fclose_ FILE *f = NULL; int r; if (!path) path = "/etc/login.defs"; - r = fopen_unlocked(path, "re", &f); + r = chase_symlinks_and_fopen_unlocked(path, root, CHASE_PREFIX_ROOT, "re", &f, NULL); if (r == -ENOENT) goto assign; if (r < 0) @@ -88,11 +91,11 @@ static int read_login_defs(UGIDAllocationRange *ret_defs, const char *path) { defs.system_alloc_gid_min = MIN(defs.system_gid_max - 1, (gid_t) SYSTEM_ALLOC_GID_MIN); /* Look at sys_gid_max to make sure sys_gid_min..sys_gid_max remains a valid range. */ } +#endif *ret_defs = defs; return 0; } -#endif const UGIDAllocationRange *acquire_ugid_allocation_range(void) { #if ENABLE_COMPAT_MUTABLE_UID_BOUNDARIES @@ -114,7 +117,7 @@ const UGIDAllocationRange *acquire_ugid_allocation_range(void) { static thread_local bool initialized = false; if (!initialized) { - (void) read_login_defs(&defs, NULL); + (void) read_login_defs(&defs, NULL, NULL); initialized = true; } #endif diff --git a/src/shared/user-record.h b/src/shared/user-record.h index 1f87eff6d5..2e74b910c2 100644 --- a/src/shared/user-record.h +++ b/src/shared/user-record.h @@ -43,6 +43,7 @@ typedef struct UGIDAllocationRange { gid_t system_gid_max; } UGIDAllocationRange; +int read_login_defs(UGIDAllocationRange *ret_defs, const char *path, const char *root); const UGIDAllocationRange *acquire_ugid_allocation_range(void); typedef enum UserDisposition { diff --git a/src/sysusers/sysusers.c b/src/sysusers/sysusers.c index 7349e9fcb9..987950d602 100644 --- a/src/sysusers/sysusers.c +++ b/src/sysusers/sysusers.c @@ -26,6 +26,7 @@ #include "strv.h" #include "tmpfile-util-label.h" #include "uid-range.h" +#include "user-record.h" #include "user-util.h" #include "utf8.h" #include "util.h" @@ -1949,10 +1950,25 @@ static int run(int argc, char *argv[]) { return log_error_errno(errno, "Failed to set SYSTEMD_NSS_BYPASS_SYNTHETIC environment variable: %m"); if (!uid_range) { - /* Default to default range of 1..SYSTEM_UID_MAX */ - r = uid_range_add(&uid_range, &n_uid_range, 1, SYSTEM_UID_MAX); + /* Default to default range of SYSTEMD_UID_MIN..SYSTEM_UID_MAX. */ + UGIDAllocationRange defs; + + r = read_login_defs(&defs, NULL, arg_root); if (r < 0) - return log_oom(); + return log_error_errno(r, "Failed to read %s%s: %m", + strempty(arg_root), "/etc/login.defs"); + + /* We pick a range that very conservative: we look at compiled-in maximum and the value in + * /etc/login.defs. That way the uids/gids which we allocate will be interpreted correctly, + * even if /etc/login.defs is removed later. (The bottom bound doesn't matter much, since + * it's only used during allocation, so we use the configured value directly). */ + uid_t begin = defs.system_alloc_uid_min, + end = MIN3((uid_t) SYSTEM_UID_MAX, defs.system_uid_max, defs.system_gid_max); + if (begin < end) { + r = uid_range_add(&uid_range, &n_uid_range, begin, end - begin + 1); + if (r < 0) + return log_oom(); + } } r = add_implicit(); diff --git a/src/test/test-user-record.c b/src/test/test-user-record.c index fcab61d694..d623706648 100644 --- a/src/test/test-user-record.c +++ b/src/test/test-user-record.c @@ -3,10 +3,55 @@ #include #include +#include "fd-util.h" +#include "fileio.h" #include "format-util.h" +#include "fs-util.h" +#include "tmpfile-util.h" #include "tests.h" #include "user-record.h" +static void test_read_login_defs(const char *path) { + log_info("/* %s(\"%s\") */", __func__, path ?: ""); + + _cleanup_(unlink_tempfilep) char name[] = "/tmp/test-user-record.XXXXXX"; + _cleanup_fclose_ FILE *f = NULL; + if (!path) { + assert_se(fmkostemp_safe(name, "r+", &f) == 0); + fprintf(f, + "SYS_UID_MIN "UID_FMT"\n" + "SYS_UID_MAX "UID_FMT"\n" + "SYS_GID_MIN "GID_FMT"\n" + "SYS_GID_MAX "GID_FMT"\n", + SYSTEM_ALLOC_UID_MIN + 5, + SYSTEM_UID_MAX + 5, + SYSTEM_ALLOC_GID_MIN + 5, + SYSTEM_GID_MAX + 5); + assert_se(fflush_and_check(f) >= 0); + } + + UGIDAllocationRange defs; + assert_se(read_login_defs(&defs, path ?: name, NULL) >= 0); + + log_info("system_alloc_uid_min="UID_FMT, defs.system_alloc_uid_min); + log_info("system_uid_max="UID_FMT, defs.system_uid_max); + log_info("system_alloc_gid_min="GID_FMT, defs.system_alloc_gid_min); + log_info("system_gid_max="GID_FMT, defs.system_gid_max); + + if (!path) { + uid_t offset = ENABLE_COMPAT_MUTABLE_UID_BOUNDARIES ? 5 : 0; + assert_se(defs.system_alloc_uid_min == SYSTEM_ALLOC_UID_MIN + offset); + assert_se(defs.system_uid_max == SYSTEM_UID_MAX + offset); + assert_se(defs.system_alloc_gid_min == SYSTEM_ALLOC_GID_MIN + offset); + assert_se(defs.system_gid_max == SYSTEM_GID_MAX + offset); + } else if (streq(path, "/dev/null")) { + assert_se(defs.system_alloc_uid_min == SYSTEM_ALLOC_UID_MIN); + assert_se(defs.system_uid_max == SYSTEM_UID_MAX); + assert_se(defs.system_alloc_gid_min == SYSTEM_ALLOC_GID_MIN); + assert_se(defs.system_gid_max == SYSTEM_GID_MAX); + } +} + static void test_acquire_ugid_allocation_range(void) { log_info("/* %s */", __func__); @@ -48,6 +93,9 @@ static void test_gid_is_system(void) { int main(int argc, char *argv[]) { test_setup_logging(LOG_DEBUG); + test_read_login_defs("/dev/null"); + test_read_login_defs("/etc/login.defs"); + test_read_login_defs(NULL); test_acquire_ugid_allocation_range(); test_uid_is_system(); test_gid_is_system(); diff --git a/test/test-sysusers.sh.in b/test/test-sysusers.sh.in index 39d238c1f7..6e133cc841 100755 --- a/test/test-sysusers.sh.in +++ b/test/test-sysusers.sh.in @@ -20,19 +20,22 @@ prepare_testdir() { return 0 } +[ @SYSTEM_UID_MAX@ -lt @SYSTEM_GID_MAX@ ] && system_guid_max=@SYSTEM_UID_MAX@ || system_guid_max=@SYSTEM_GID_MAX@ + preprocess() { - sed -e "s/SYSTEM_UID_MAX/@SYSTEM_UID_MAX@/g" \ - -e "s/SYSTEM_GID_MAX/@SYSTEM_GID_MAX@/g" \ - -e "s#NOLOGIN#@NOLOGIN@#g" "$1" + m=${2:-$system_guid_max} + + sed -e "s/SYSTEM_UGID_MAX/$m/g; + s#NOLOGIN#@NOLOGIN@#g" "$1" } compare() { - if ! diff -u $TESTDIR/etc/passwd <(preprocess $1.expected-passwd); then + if ! diff -u $TESTDIR/etc/passwd <(preprocess $1.expected-passwd $3); then echo "**** Unexpected output for $f $2" exit 1 fi - if ! diff -u $TESTDIR/etc/group <(preprocess $1.expected-group); then + if ! diff -u $TESTDIR/etc/group <(preprocess $1.expected-group $3); then echo "**** Unexpected output for $f $2" exit 1 fi @@ -97,6 +100,52 @@ compare $SOURCE/inline "(--inline --replace=…)" rm -f $TESTDIR/etc/sysusers.d/* $TESTDIR/usr/lib/sysusers.d/* +cat >$TESTDIR/etc/login.defs <