From: Lennart Poettering Date: Mon, 10 May 2021 14:41:46 +0000 (+0200) Subject: sd-device: use strjoina() more again in sd_device_new_from_subsystem_sysname() X-Git-Tag: v249-rc1~180 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f5e775973a22e10e0813b56cb3e43d5d415979f7;p=thirdparty%2Fsystemd.git sd-device: use strjoina() more again in sd_device_new_from_subsystem_sysname() This reverts a major part of: e17c95af8e450caacde692875b30675cea75211f Using format strings for concatenating strings is pretty unefficient, and using PATH_MAX buffers unpretty as well. Let's revert to using strjoina() as before. However, to fix the fuzz issue at hand, let's explicitly verify the two input strings ensuring they are valid path names. This includes a length check (to 2K each), thus making things prettier, faster and using less memory again. --- diff --git a/src/libsystemd/sd-device/sd-device.c b/src/libsystemd/sd-device/sd-device.c index d0cba5b8600..363e4f2dd0a 100644 --- a/src/libsystemd/sd-device/sd-device.c +++ b/src/libsystemd/sd-device/sd-device.c @@ -244,71 +244,103 @@ _public_ int sd_device_new_from_devnum(sd_device **ret, char type, dev_t devnum) return sd_device_new_from_syspath(ret, syspath); } -_public_ int sd_device_new_from_subsystem_sysname(sd_device **ret, const char *subsystem, const char *sysname) { - char syspath[PATH_MAX], *name; +static int device_strjoin_new( + const char *a, + const char *b, + const char *c, + const char *d, + sd_device **ret) { + + const char *p; + int r; + + p = strjoina(a, b, c, d); + if (access(p, F_OK) < 0) + return IN_SET(errno, ENOENT, ENAMETOOLONG) ? 0 : -errno; /* If this sysfs is too long then it doesn't exist either */ + + r = sd_device_new_from_syspath(ret, p); + if (r < 0) + return r; + + return 1; +} + +_public_ int sd_device_new_from_subsystem_sysname( + sd_device **ret, + const char *subsystem, + const char *sysname) { + + const char *s; + char *name; + int r; assert_return(ret, -EINVAL); - assert_return(subsystem, -EINVAL); - assert_return(sysname, -EINVAL); - assert_return(strlen(sysname) < PATH_MAX - strlen("/sys/bus/"), -ENAMETOOLONG); + assert_return(path_is_normalized(subsystem), -EINVAL); + assert_return(path_is_normalized(sysname), -EINVAL); if (streq(subsystem, "subsystem")) { - if (snprintf_ok(syspath, sizeof syspath, "/sys/subsystem/%s", sysname) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); - - if (snprintf_ok(syspath, sizeof syspath, "/sys/bus/%s", sysname) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); - if (snprintf_ok(syspath, sizeof syspath, "/sys/class/%s", sysname) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); + FOREACH_STRING(s, "/sys/subsystem/", "/sys/bus/", "/sys/class/") { + r = device_strjoin_new(s, sysname, NULL, NULL, ret); + if (r < 0) + return r; + if (r > 0) + return 0; + } } else if (streq(subsystem, "module")) { - if (snprintf_ok(syspath, sizeof syspath, "/sys/module/%s", sysname) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); + + r = device_strjoin_new("/sys/module/", sysname, NULL, NULL, ret); + if (r < 0) + return r; + if (r > 0) + return 0; } else if (streq(subsystem, "drivers")) { - const char *subsys, *sep; + const char *sep; sep = strchr(sysname, ':'); if (sep && sep[1] != '\0') { /* Require ":" and something non-empty after that. */ - subsys = memdupa_suffix0(sysname, sep - sysname); + const char *subsys; - if (snprintf_ok(syspath, sizeof syspath, "/sys/subsystem/%s/drivers/%s", subsys, sep + 1) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); + subsys = memdupa_suffix0(sysname, sep - sysname); + sep++; - if (snprintf_ok(syspath, sizeof syspath, "/sys/bus/%s/drivers/%s", subsys, sep + 1) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); + FOREACH_STRING(s, "/sys/subsystem/", "/sys/bus/") { + r = device_strjoin_new(s, subsys, "/drivers/", sep, ret); + if (r < 0) + return r; + if (r > 0) + return 0; + } } } /* translate sysname back to sysfs filename */ name = strdupa(sysname); - for (size_t i = 0; name[i]; i++) if (name[i] == '/') name[i] = '!'; - if (snprintf_ok(syspath, sizeof syspath, "/sys/subsystem/%s/devices/%s", subsystem, name) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); - - if (snprintf_ok(syspath, sizeof syspath, "/sys/bus/%s/devices/%s", subsystem, name) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); + FOREACH_STRING(s, "/sys/subsystem/", "/sys/bus/") { + r = device_strjoin_new(s, subsystem, "/devices/", name, ret); + if (r < 0) + return r; + if (r > 0) + return 0; + } - if (snprintf_ok(syspath, sizeof syspath, "/sys/class/%s/%s", subsystem, name) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); + r = device_strjoin_new("/sys/class/", subsystem, "/", name, ret); + if (r < 0) + return r; + if (r > 0) + return 0; - if (snprintf_ok(syspath, sizeof syspath, "/sys/firmware/%s/%s", subsystem, sysname) && - access(syspath, F_OK) >= 0) - return sd_device_new_from_syspath(ret, syspath); + r = device_strjoin_new("/sys/firmware/", subsystem, "/", sysname, ret); + if (r < 0) + return r; + if (r > 0) + return 0; return -ENODEV; } diff --git a/src/test/test-udev-util.c b/src/test/test-udev-util.c index f34c5c27d30..b87a90f7661 100644 --- a/src/test/test-udev-util.c +++ b/src/test/test-udev-util.c @@ -252,7 +252,7 @@ static void test_udev_resolve_subsys_kernel(void) { test_udev_resolve_subsys_kernel_one("hoge", false, -EINVAL, NULL); test_udev_resolve_subsys_kernel_one("[hoge", false, -EINVAL, NULL); test_udev_resolve_subsys_kernel_one("[hoge/foo", false, -EINVAL, NULL); - test_udev_resolve_subsys_kernel_one("[hoge/]", false, -ENODEV, NULL); + test_udev_resolve_subsys_kernel_one("[hoge/]", false, -EINVAL, NULL); test_udev_resolve_subsys_kernel_one("[net/lo]", false, 0, "/sys/devices/virtual/net/lo"); test_udev_resolve_subsys_kernel_one("[net/lo]/", false, 0, "/sys/devices/virtual/net/lo");