From: Matt Fleming <matt@codeblueprint.co.uk>
To: Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"H . Peter Anvin" <hpa@zytor.com>
Cc: Jeremy Compostella <jeremy.compostella@intel.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org,
Matt Fleming <matt@codeblueprint.co.uk>,
Arnd Bergmann <arnd@arndb.de>
Subject: [PATCH 2/5] efibc: Fix excessive stack footprint warning
Date: Fri, 6 May 2016 22:39:28 +0100 [thread overview]
Message-ID: <1462570771-13324-3-git-send-email-matt@codeblueprint.co.uk> (raw)
In-Reply-To: <1462570771-13324-1-git-send-email-matt@codeblueprint.co.uk>
From: Jeremy Compostella <jeremy.compostella@intel.com>
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>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[ Updated changelog to include gcc error ]
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
---
drivers/firmware/efi/efibc.c | 34 +++++++++++++++++++++++-----------
1 file changed, 23 insertions(+), 11 deletions(-)
diff --git a/drivers/firmware/efi/efibc.c b/drivers/firmware/efi/efibc.c
index 2e0c7ccd9d9e..8dd0c7085e59 100644
--- a/drivers/firmware/efi/efibc.c
+++ b/drivers/firmware/efi/efibc.c
@@ -17,6 +17,7 @@
#include <linux/efi.h>
#include <linux/module.h>
#include <linux/reboot.h>
+#include <linux/slab.h>
static void efibc_str_to_str16(const char *str, efi_char16_t *str16)
{
@@ -28,41 +29,52 @@ static void efibc_str_to_str16(const char *str, efi_char16_t *str16)
str16[i] = '\0';
}
-static void efibc_set_variable(const char *name, const char *value)
+static int efibc_set_variable(const char *name, const char *value)
{
int ret;
efi_guid_t guid = LINUX_EFI_LOADER_ENTRY_GUID;
- struct efivar_entry entry;
+ struct efivar_entry *entry;
size_t size = (strlen(value) + 1) * sizeof(efi_char16_t);
- if (size > sizeof(entry.var.Data))
+ if (size > sizeof(entry->var.Data)) {
pr_err("value is too large");
+ return -EINVAL;
+ }
- efibc_str_to_str16(name, entry.var.VariableName);
- efibc_str_to_str16(value, (efi_char16_t *)entry.var.Data);
- memcpy(&entry.var.VendorGuid, &guid, sizeof(guid));
+ entry = kmalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry) {
+ pr_err("failed to allocate efivar entry");
+ return -ENOMEM;
+ }
- ret = efivar_entry_set(&entry,
+ efibc_str_to_str16(name, entry->var.VariableName);
+ efibc_str_to_str16(value, (efi_char16_t *)entry->var.Data);
+ memcpy(&entry->var.VendorGuid, &guid, sizeof(guid));
+
+ ret = efivar_entry_set(entry,
EFI_VARIABLE_NON_VOLATILE
| EFI_VARIABLE_BOOTSERVICE_ACCESS
| EFI_VARIABLE_RUNTIME_ACCESS,
- size, entry.var.Data, NULL);
+ size, entry->var.Data, NULL);
if (ret)
pr_err("failed to set %s EFI variable: 0x%x\n",
name, ret);
+
+ kfree(entry);
+ return ret;
}
static int efibc_reboot_notifier_call(struct notifier_block *notifier,
unsigned long event, void *data)
{
const char *reason = "shutdown";
+ int ret;
if (event == SYS_RESTART)
reason = "reboot";
- efibc_set_variable("LoaderEntryRebootReason", reason);
-
- if (!data)
+ ret = efibc_set_variable("LoaderEntryRebootReason", reason);
+ if (ret || !data)
return NOTIFY_DONE;
efibc_set_variable("LoaderEntryOneShot", (char *)data);
--
2.7.3
next prev parent reply other threads:[~2016-05-06 21:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-06 21:39 [GIT PULL 0/5] EFI changes for v4.7 Matt Fleming
2016-05-06 21:39 ` [PATCH 1/5] efi/capsule: Make efi_capsule_pending() lockless Matt Fleming
2016-05-07 6:33 ` [tip:efi/core] " tip-bot for Matt Fleming
2016-05-06 21:39 ` Matt Fleming [this message]
2016-05-07 6:34 ` [tip:efi/core] efibc: Fix excessive stack footprint warning tip-bot for Jeremy Compostella
2016-05-09 23:41 ` [PATCH 2/5] " Elliott, Robert (Persistent Memory)
2016-05-10 8:40 ` Compostella, Jeremy
2016-05-11 12:43 ` Matt Fleming
2016-05-11 15:16 ` Compostella, Jeremy
2016-05-14 19:20 ` Matt Fleming
2016-05-06 21:39 ` [PATCH 3/5] efi/capsule: Move 'capsule' to the stack in efi_capsule_supported() Matt Fleming
2016-05-07 6:34 ` [tip:efi/core] " tip-bot for Matt Fleming
2016-05-06 21:39 ` [PATCH 4/5] efi: Merge boolean flag arguments Matt Fleming
2016-05-07 6:34 ` [tip:efi/core] " tip-bot for Julia Lawall
2016-05-06 21:39 ` [PATCH 5/5] efivarfs: Make efivarfs_file_ioctl static Matt Fleming
2016-05-07 6:35 ` [tip:efi/core] efivarfs: Make efivarfs_file_ioctl() static tip-bot for Peter Jones
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