* [PATCH AUTOSEL 4.20 102/304] firmware/efi: Add NULL pointer checks in efivars API functions
[not found] <20190128154341.47195-1-sashal@kernel.org>
@ 2019-01-28 15:40 ` Sasha Levin
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From: Sasha Levin @ 2019-01-28 15:40 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Arend van Spriel, Ard Biesheuvel, Andy Lutomirski,
Bhupesh Sharma, Borislav Petkov, Dave Hansen, Eric Snowberg,
Hans de Goede, Joe Perches, Julien Thierry, Linus Torvalds,
Marc Zyngier, Matt Fleming, Nathan Chancellor, Peter Zijlstra,
Sai Praneeth Prakhya, Sedat Dilek, Thomas Gleixner, YiFei Zhu
From: Arend van Spriel <arend.vanspriel@broadcom.com>
[ Upstream commit ab2180a15ce54739fed381efb4cb12e78dfb1561 ]
Since commit:
ce2e6db554fa ("brcmfmac: Add support for getting nvram contents from EFI variables")
we have a device driver accessing the efivars API. Several functions in
the efivars API assume __efivars is set, i.e., that they will be accessed
only after efivars_register() has been called. However, the following NULL
pointer access was reported calling efivar_entry_size() from the brcmfmac
device driver:
Unable to handle kernel NULL pointer dereference at virtual address 00000008
pgd = 60bfa5f1
[00000008] *pgd=00000000
Internal error: Oops: 5 [#1] SMP ARM
...
Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
Workqueue: events request_firmware_work_func
PC is at efivar_entry_size+0x28/0x90
LR is at brcmf_fw_complete_request+0x3f8/0x8d4 [brcmfmac]
pc : [<c0c40718>] lr : [<bf2a3ef4>] psr: a00d0113
sp : ede7fe28 ip : ee983410 fp : c1787f30
r10: 00000000 r9 : 00000000 r8 : bf2b2258
r7 : ee983000 r6 : c1604c48 r5 : ede7fe88 r4 : edf337c0
r3 : 00000000 r2 : 00000000 r1 : ede7fe88 r0 : c17712c8
Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none
Control: 10c5387d Table: ad16804a DAC: 00000051
Disassembly showed that the local static variable __efivars is NULL,
which is not entirely unexpected given that it is a non-EFI platform.
So add a NULL pointer check to efivar_entry_size(), and to related
functions while at it. In efivars_register() a couple of sanity checks
are added as well.
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eric Snowberg <eric.snowberg@oracle.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Julien Thierry <julien.thierry@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20181129171230.18699-9-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/firmware/efi/vars.c | 99 +++++++++++++++++++++++++++++--------
1 file changed, 78 insertions(+), 21 deletions(-)
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 9336ffdf6e2c..fceaafd67ec6 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -318,7 +318,12 @@ EXPORT_SYMBOL_GPL(efivar_variable_is_removable);
static efi_status_t
check_var_size(u32 attributes, unsigned long size)
{
- const struct efivar_operations *fops = __efivars->ops;
+ const struct efivar_operations *fops;
+
+ if (!__efivars)
+ return EFI_UNSUPPORTED;
+
+ fops = __efivars->ops;
if (!fops->query_variable_store)
return EFI_UNSUPPORTED;
@@ -329,7 +334,12 @@ check_var_size(u32 attributes, unsigned long size)
static efi_status_t
check_var_size_nonblocking(u32 attributes, unsigned long size)
{
- const struct efivar_operations *fops = __efivars->ops;
+ const struct efivar_operations *fops;
+
+ if (!__efivars)
+ return EFI_UNSUPPORTED;
+
+ fops = __efivars->ops;
if (!fops->query_variable_store)
return EFI_UNSUPPORTED;
@@ -429,13 +439,18 @@ static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
void *data, bool duplicates, struct list_head *head)
{
- const struct efivar_operations *ops = __efivars->ops;
+ const struct efivar_operations *ops;
unsigned long variable_name_size = 1024;
efi_char16_t *variable_name;
efi_status_t status;
efi_guid_t vendor_guid;
int err = 0;
+ if (!__efivars)
+ return -EFAULT;
+
+ ops = __efivars->ops;
+
variable_name = kzalloc(variable_name_size, GFP_KERNEL);
if (!variable_name) {
printk(KERN_ERR "efivars: Memory allocation failed.\n");
@@ -583,12 +598,14 @@ static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
*/
int __efivar_entry_delete(struct efivar_entry *entry)
{
- const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
- status = ops->set_variable(entry->var.VariableName,
- &entry->var.VendorGuid,
- 0, 0, NULL);
+ if (!__efivars)
+ return -EINVAL;
+
+ status = __efivars->ops->set_variable(entry->var.VariableName,
+ &entry->var.VendorGuid,
+ 0, 0, NULL);
return efi_status_to_err(status);
}
@@ -607,12 +624,17 @@ EXPORT_SYMBOL_GPL(__efivar_entry_delete);
*/
int efivar_entry_delete(struct efivar_entry *entry)
{
- const struct efivar_operations *ops = __efivars->ops;
+ const struct efivar_operations *ops;
efi_status_t status;
if (down_interruptible(&efivars_lock))
return -EINTR;
+ if (!__efivars) {
+ up(&efivars_lock);
+ return -EINVAL;
+ }
+ ops = __efivars->ops;
status = ops->set_variable(entry->var.VariableName,
&entry->var.VendorGuid,
0, 0, NULL);
@@ -650,13 +672,19 @@ EXPORT_SYMBOL_GPL(efivar_entry_delete);
int efivar_entry_set(struct efivar_entry *entry, u32 attributes,
unsigned long size, void *data, struct list_head *head)
{
- const struct efivar_operations *ops = __efivars->ops;
+ const struct efivar_operations *ops;
efi_status_t status;
efi_char16_t *name = entry->var.VariableName;
efi_guid_t vendor = entry->var.VendorGuid;
if (down_interruptible(&efivars_lock))
return -EINTR;
+
+ if (!__efivars) {
+ up(&efivars_lock);
+ return -EINVAL;
+ }
+ ops = __efivars->ops;
if (head && efivar_entry_find(name, vendor, head, false)) {
up(&efivars_lock);
return -EEXIST;
@@ -687,12 +715,17 @@ static int
efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor,
u32 attributes, unsigned long size, void *data)
{
- const struct efivar_operations *ops = __efivars->ops;
+ const struct efivar_operations *ops;
efi_status_t status;
if (down_trylock(&efivars_lock))
return -EBUSY;
+ if (!__efivars) {
+ up(&efivars_lock);
+ return -EINVAL;
+ }
+
status = check_var_size_nonblocking(attributes,
size + ucs2_strsize(name, 1024));
if (status != EFI_SUCCESS) {
@@ -700,6 +733,7 @@ efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor,
return -ENOSPC;
}
+ ops = __efivars->ops;
status = ops->set_variable_nonblocking(name, &vendor, attributes,
size, data);
@@ -727,9 +761,13 @@ efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor,
int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes,
bool block, unsigned long size, void *data)
{
- const struct efivar_operations *ops = __efivars->ops;
+ const struct efivar_operations *ops;
efi_status_t status;
+ if (!__efivars)
+ return -EINVAL;
+
+ ops = __efivars->ops;
if (!ops->query_variable_store)
return -ENOSYS;
@@ -829,13 +867,18 @@ EXPORT_SYMBOL_GPL(efivar_entry_find);
*/
int efivar_entry_size(struct efivar_entry *entry, unsigned long *size)
{
- const struct efivar_operations *ops = __efivars->ops;
+ const struct efivar_operations *ops;
efi_status_t status;
*size = 0;
if (down_interruptible(&efivars_lock))
return -EINTR;
+ if (!__efivars) {
+ up(&efivars_lock);
+ return -EINVAL;
+ }
+ ops = __efivars->ops;
status = ops->get_variable(entry->var.VariableName,
&entry->var.VendorGuid, NULL, size, NULL);
up(&efivars_lock);
@@ -861,12 +904,14 @@ EXPORT_SYMBOL_GPL(efivar_entry_size);
int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
unsigned long *size, void *data)
{
- const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
- status = ops->get_variable(entry->var.VariableName,
- &entry->var.VendorGuid,
- attributes, size, data);
+ if (!__efivars)
+ return -EINVAL;
+
+ status = __efivars->ops->get_variable(entry->var.VariableName,
+ &entry->var.VendorGuid,
+ attributes, size, data);
return efi_status_to_err(status);
}
@@ -882,14 +927,19 @@ EXPORT_SYMBOL_GPL(__efivar_entry_get);
int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
unsigned long *size, void *data)
{
- const struct efivar_operations *ops = __efivars->ops;
efi_status_t status;
if (down_interruptible(&efivars_lock))
return -EINTR;
- status = ops->get_variable(entry->var.VariableName,
- &entry->var.VendorGuid,
- attributes, size, data);
+
+ if (!__efivars) {
+ up(&efivars_lock);
+ return -EINVAL;
+ }
+
+ status = __efivars->ops->get_variable(entry->var.VariableName,
+ &entry->var.VendorGuid,
+ attributes, size, data);
up(&efivars_lock);
return efi_status_to_err(status);
@@ -921,7 +971,7 @@ EXPORT_SYMBOL_GPL(efivar_entry_get);
int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
unsigned long *size, void *data, bool *set)
{
- const struct efivar_operations *ops = __efivars->ops;
+ const struct efivar_operations *ops;
efi_char16_t *name = entry->var.VariableName;
efi_guid_t *vendor = &entry->var.VendorGuid;
efi_status_t status;
@@ -940,6 +990,11 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
if (down_interruptible(&efivars_lock))
return -EINTR;
+ if (!__efivars) {
+ err = -EINVAL;
+ goto out;
+ }
+
/*
* Ensure that the available space hasn't shrunk below the safe level
*/
@@ -956,6 +1011,8 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
}
}
+ ops = __efivars->ops;
+
status = ops->set_variable(name, vendor, attributes, *size, data);
if (status != EFI_SUCCESS) {
err = efi_status_to_err(status);
--
2.19.1
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2019-01-28 15:40 ` [PATCH AUTOSEL 4.20 102/304] firmware/efi: Add NULL pointer checks in efivars API functions Sasha Levin
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