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Merge tag 'efi-for-3.9-rc2' into x86/urgent
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EFI changes for v3.9-rc2,

  * Make the EFI variable code more paranoid about running out of
    space in NVRAM, since this is the root cause of the recent issue
    where machines refuse to boot - from Matthew Garrett.

  * Some efivarfs patches that fix regressions introduced in v3.9-rc1.

Signed-off-by: H. Peter Anvin <[email protected]>
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H. Peter Anvin committed Mar 7, 2013
2 parents 60f583d + feff5dc commit cc67708
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Showing 2 changed files with 155 additions and 34 deletions.
130 changes: 96 additions & 34 deletions drivers/firmware/efivars.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -426,6 +426,44 @@ get_var_data(struct efivars *efivars, struct efi_variable *var)
return status;
}

static efi_status_t
check_var_size_locked(struct efivars *efivars, u32 attributes,
unsigned long size)
{
u64 storage_size, remaining_size, max_size;
efi_status_t status;
const struct efivar_operations *fops = efivars->ops;

if (!efivars->ops->query_variable_info)
return EFI_UNSUPPORTED;

status = fops->query_variable_info(attributes, &storage_size,
&remaining_size, &max_size);

if (status != EFI_SUCCESS)
return status;

if (!storage_size || size > remaining_size || size > max_size ||
(remaining_size - size) < (storage_size / 2))
return EFI_OUT_OF_RESOURCES;

return status;
}


static efi_status_t
check_var_size(struct efivars *efivars, u32 attributes, unsigned long size)
{
efi_status_t status;
unsigned long flags;

spin_lock_irqsave(&efivars->lock, flags);
status = check_var_size_locked(efivars, attributes, size);
spin_unlock_irqrestore(&efivars->lock, flags);

return status;
}

static ssize_t
efivar_guid_read(struct efivar_entry *entry, char *buf)
{
Expand Down Expand Up @@ -547,11 +585,16 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
}

spin_lock_irq(&efivars->lock);
status = efivars->ops->set_variable(new_var->VariableName,
&new_var->VendorGuid,
new_var->Attributes,
new_var->DataSize,
new_var->Data);

status = check_var_size_locked(efivars, new_var->Attributes,
new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));

if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED)
status = efivars->ops->set_variable(new_var->VariableName,
&new_var->VendorGuid,
new_var->Attributes,
new_var->DataSize,
new_var->Data);

spin_unlock_irq(&efivars->lock);

Expand Down Expand Up @@ -702,8 +745,7 @@ static ssize_t efivarfs_file_write(struct file *file,
u32 attributes;
struct inode *inode = file->f_mapping->host;
unsigned long datasize = count - sizeof(attributes);
unsigned long newdatasize;
u64 storage_size, remaining_size, max_size;
unsigned long newdatasize, varsize;
ssize_t bytes = 0;

if (count < sizeof(attributes))
Expand All @@ -722,28 +764,18 @@ static ssize_t efivarfs_file_write(struct file *file,
* amounts of memory. Pick a default size of 64K if
* QueryVariableInfo() isn't supported by the firmware.
*/
spin_lock_irq(&efivars->lock);

if (!efivars->ops->query_variable_info)
status = EFI_UNSUPPORTED;
else {
const struct efivar_operations *fops = efivars->ops;
status = fops->query_variable_info(attributes, &storage_size,
&remaining_size, &max_size);
}

spin_unlock_irq(&efivars->lock);
varsize = datasize + utf16_strsize(var->var.VariableName, 1024);
status = check_var_size(efivars, attributes, varsize);

if (status != EFI_SUCCESS) {
if (status != EFI_UNSUPPORTED)
return efi_status_to_err(status);

remaining_size = 65536;
if (datasize > 65536)
return -ENOSPC;
}

if (datasize > remaining_size)
return -ENOSPC;

data = kmalloc(datasize, GFP_KERNEL);
if (!data)
return -ENOMEM;
Expand All @@ -765,6 +797,19 @@ static ssize_t efivarfs_file_write(struct file *file,
*/
spin_lock_irq(&efivars->lock);

/*
* Ensure that the available space hasn't shrunk below the safe level
*/

status = check_var_size_locked(efivars, attributes, varsize);

if (status != EFI_SUCCESS && status != EFI_UNSUPPORTED) {
spin_unlock_irq(&efivars->lock);
kfree(data);

return efi_status_to_err(status);
}

status = efivars->ops->set_variable(var->var.VariableName,
&var->var.VendorGuid,
attributes, datasize,
Expand Down Expand Up @@ -929,8 +974,8 @@ static bool efivarfs_valid_name(const char *str, int len)
if (len < GUID_LEN + 2)
return false;

/* GUID should be right after the first '-' */
if (s - 1 != strchr(str, '-'))
/* GUID must be preceded by a '-' */
if (*(s - 1) != '-')
return false;

/*
Expand Down Expand Up @@ -1118,15 +1163,22 @@ static struct dentry_operations efivarfs_d_ops = {

static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
{
struct dentry *d;
struct qstr q;
int err;

q.name = name;
q.len = strlen(name);

if (efivarfs_d_hash(NULL, NULL, &q))
return NULL;
err = efivarfs_d_hash(NULL, NULL, &q);
if (err)
return ERR_PTR(err);

d = d_alloc(parent, &q);
if (d)
return d;

return d_alloc(parent, &q);
return ERR_PTR(-ENOMEM);
}

static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
Expand All @@ -1136,6 +1188,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
struct efivar_entry *entry, *n;
struct efivars *efivars = &__efivars;
char *name;
int err = -ENOMEM;

efivarfs_sb = sb;

Expand Down Expand Up @@ -1186,8 +1239,10 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
goto fail_name;

dentry = efivarfs_alloc_dentry(root, name);
if (!dentry)
if (IS_ERR(dentry)) {
err = PTR_ERR(dentry);
goto fail_inode;
}

/* copied by the above to local storage in the dentry. */
kfree(name);
Expand All @@ -1214,7 +1269,7 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
fail_name:
kfree(name);
fail:
return -ENOMEM;
return err;
}

static struct dentry *efivarfs_mount(struct file_system_type *fs_type,
Expand Down Expand Up @@ -1345,7 +1400,6 @@ static int efi_pstore_write(enum pstore_type_id type,
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
struct efivars *efivars = psi->data;
int i, ret = 0;
u64 storage_space, remaining_space, max_variable_size;
efi_status_t status = EFI_NOT_FOUND;
unsigned long flags;

Expand All @@ -1365,11 +1419,11 @@ static int efi_pstore_write(enum pstore_type_id type,
* size: a size of logging data
* DUMP_NAME_LEN * 2: a maximum size of variable name
*/
status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
&storage_space,
&remaining_space,
&max_variable_size);
if (status || remaining_space < size + DUMP_NAME_LEN * 2) {

status = check_var_size_locked(efivars, PSTORE_EFI_ATTRIBUTES,
size + DUMP_NAME_LEN * 2);

if (status) {
spin_unlock_irqrestore(&efivars->lock, flags);
*id = part;
return -ENOSPC;
Expand Down Expand Up @@ -1544,6 +1598,14 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
return -EINVAL;
}

status = check_var_size_locked(efivars, new_var->Attributes,
new_var->DataSize + utf16_strsize(new_var->VariableName, 1024));

if (status && status != EFI_UNSUPPORTED) {
spin_unlock_irq(&efivars->lock);
return efi_status_to_err(status);
}

/* now *really* create the variable via EFI */
status = efivars->ops->set_variable(new_var->VariableName,
&new_var->VendorGuid,
Expand Down
59 changes: 59 additions & 0 deletions tools/testing/selftests/efivarfs/efivarfs.sh
View file
Original file line number Diff line number Diff line change
Expand Up @@ -125,6 +125,63 @@ test_open_unlink()
./open-unlink $file
}

# test that we can create a range of filenames
test_valid_filenames()
{
local attrs='\x07\x00\x00\x00'
local ret=0

local file_list="abc dump-type0-11-1-1362436005 1234 -"
for f in $file_list; do
local file=$efivarfs_mount/$f-$test_guid

printf "$attrs\x00" > $file

if [ ! -e $file ]; then
echo "$file could not be created" >&2
ret=1
else
rm $file
fi
done

exit $ret
}

test_invalid_filenames()
{
local attrs='\x07\x00\x00\x00'
local ret=0

local file_list="
-1234-1234-1234-123456789abc
foo
foo-bar
-foo-
foo-barbazba-foob-foob-foob-foobarbazfoo
foo-------------------------------------
-12345678-1234-1234-1234-123456789abc
a-12345678=1234-1234-1234-123456789abc
a-12345678-1234=1234-1234-123456789abc
a-12345678-1234-1234=1234-123456789abc
a-12345678-1234-1234-1234=123456789abc
1112345678-1234-1234-1234-123456789abc"

for f in $file_list; do
local file=$efivarfs_mount/$f

printf "$attrs\x00" 2>/dev/null > $file

if [ -e $file ]; then
echo "Creating $file should have failed" >&2
rm $file
ret=1
fi
done

exit $ret
}

check_prereqs

rc=0
Expand All @@ -135,5 +192,7 @@ run_test test_create_read
run_test test_delete
run_test test_zero_size_delete
run_test test_open_unlink
run_test test_valid_filenames
run_test test_invalid_filenames

exit $rc

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