efibc: Fix excessive stack footprint warning
GCC complains about a newly added file for the EFI Bootloader Control: drivers/firmware/efi/efibc.c: In function 'efibc_set_variable': drivers/firmware/efi/efibc.c:53:1: error: the frame size of 2272 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] The problem is the declaration of a local variable of type struct efivar_entry, which is by itself larger than the warning limit of 1024 bytes. Use dynamic memory allocation instead of stack memory for the entry object. This patch also fixes a potential buffer overflow. Reported-by: Ingo Molnar <mingo@kernel.org> Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com> [ Updated changelog to include GCC error ] Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1462570771-13324-3-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -17,6 +17,7 @@
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#include <linux/efi.h>
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#include <linux/module.h>
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#include <linux/reboot.h>
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#include <linux/slab.h>
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static void efibc_str_to_str16(const char *str, efi_char16_t *str16)
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{
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@ -28,41 +29,52 @@ static void efibc_str_to_str16(const char *str, efi_char16_t *str16)
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str16[i] = '\0';
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}
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static void efibc_set_variable(const char *name, const char *value)
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static int efibc_set_variable(const char *name, const char *value)
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{
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int ret;
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efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID;
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struct efivar_entry entry;
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struct efivar_entry *entry;
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size_t size = (strlen(value) + 1) * sizeof(efi_char16_t);
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if (size > sizeof(entry.var.Data))
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if (size > sizeof(entry->var.Data)) {
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pr_err("value is too large");
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return -EINVAL;
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}
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efibc_str_to_str16(name, entry.var.VariableName);
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efibc_str_to_str16(value, (efi_char16_t *)entry.var.Data);
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memcpy(&entry.var.VendorGuid, &guid, sizeof(guid));
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entry = kmalloc(sizeof(*entry), GFP_KERNEL);
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if (!entry) {
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pr_err("failed to allocate efivar entry");
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return -ENOMEM;
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}
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ret = efivar_entry_set(&entry,
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efibc_str_to_str16(name, entry->var.VariableName);
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efibc_str_to_str16(value, (efi_char16_t *)entry->var.Data);
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memcpy(&entry->var.VendorGuid, &guid, sizeof(guid));
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ret = efivar_entry_set(entry,
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EFI_VARIABLE_NON_VOLATILE
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| EFI_VARIABLE_BOOTSERVICE_ACCESS
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| EFI_VARIABLE_RUNTIME_ACCESS,
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size, entry.var.Data, NULL);
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size, entry->var.Data, NULL);
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if (ret)
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pr_err("failed to set %s EFI variable: 0x%x\n",
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name, ret);
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kfree(entry);
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return ret;
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}
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static int efibc_reboot_notifier_call(struct notifier_block *notifier,
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unsigned long event, void *data)
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{
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const char *reason = "shutdown";
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int ret;
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if (event == SYS_RESTART)
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reason = "reboot";
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efibc_set_variable("LoaderEntryRebootReason", reason);
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if (!data)
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ret = efibc_set_variable("LoaderEntryRebootReason", reason);
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if (ret || !data)
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return NOTIFY_DONE;
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efibc_set_variable("LoaderEntryOneShot", (char *)data);
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