[PATCH AUTOSEL 6.18] modpost: Handle malformed WMI GUID strings
From: Sasha Levin <sashal@kernel.org>
Date: 2026-08-31 13:45:11
Also in:
linux-kbuild, linux-patches, lkml, platform-driver-x86, stable
Subsystem:
acpi wmi driver, documentation, kernel build + files below scripts/ (unless maintained elsewhere), the rest · Maintainers:
Armin Wolf, Jonathan Corbet, Nathan Chancellor, Nicolas Schier, Linus Torvalds
From: Armin Wolf <W_Armin@gmx.de> [ Upstream commit 3429ae7b2f02a4a6ad40d36ee06641d433d75a1b ] Some WMI GUIDs found inside binary MOF files contain both uppercase and lowercase characters. Blindly copying such GUIDs will prevent the associated WMI driver from loading automatically because the WMI GUID found inside WMI device ids always contains uppercase characters. Avoid this issue by always converting WMI GUID strings to uppercase. Also verify that the WMI GUID string actually looks like a valid GUID. Signed-off-by: Armin Wolf <W_Armin@gmx.de> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> Link: https://patch.msgid.link/20260610203453.816254-10-W_Armin@gmx.de Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- LLM Generated explanations, may be completely bogus: The background git searches finished. They didn’t turn up the modpost WMI GUID commit in this 6.18.44 tree — it’s still only a candidate. The closest related in-tree commit is `97b726eb1dc2b` (msi-wmi-platform lowercase GUID typo), which lines up with the modpost fix but doesn’t replace it. That doesn’t change the earlier conclusion: backport **YES** for 6.18.y. .../wmi/driver-development-guide.rst | 2 +- scripts/mod/file2alias.c | 28 ++++++++++++++++++- 2 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/Documentation/wmi/driver-development-guide.rst b/Documentation/wmi/driver-development-guide.rst
index 5680303ae314e..ae577a290afc3 100644
--- a/Documentation/wmi/driver-development-guide.rst
+++ b/Documentation/wmi/driver-development-guide.rst@@ -54,7 +54,7 @@ to matching WMI devices using a struct wmi_device_id table: :: static const struct wmi_device_id foo_id_table[] = { - /* Only use uppercase letters! */ + /* Using only uppercase letters is recommended */ { "936DA01F-9ABD-4D9D-80C7-02AF85C822A8", NULL }, { } };
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 4e99393a35f15..20e542a888c49 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c@@ -1253,6 +1253,8 @@ static void do_tee_entry(struct module *mod, void *symval) static void do_wmi_entry(struct module *mod, void *symval) { DEF_FIELD_ADDR(symval, wmi_device_id, guid_string); + char result[sizeof(*guid_string)]; + int i; if (strlen(*guid_string) != UUID_STRING_LEN) { warn("Invalid WMI device id 'wmi:%s' in '%s'\n",
@@ -1260,7 +1262,31 @@ static void do_wmi_entry(struct module *mod, void *symval) return; } - module_alias_printf(mod, false, WMI_MODULE_PREFIX "%s", *guid_string); + for (i = 0; i < UUID_STRING_LEN; i++) { + char value = (*guid_string)[i]; + bool valid = false; + + if (i == 8 || i == 13 || i == 18 || i == 23) { + if (value == '-') + valid = true; + } else { + if (isxdigit(value)) + valid = true; + } + + if (!valid) { + warn("Invalid character %c inside WMI GUID string '%s' in '%s'\n", + value, *guid_string, mod->name); + return; + } + + /* Some GUIDs from BMOF definitions contain lowercase characters */ + result[i] = toupper(value); + } + + result[i] = '\0'; + + module_alias_printf(mod, false, WMI_MODULE_PREFIX "%s", result); } /* Looks like: mhi:S */
--
2.53.0