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-   -   Wipe buffer even if vamlloc fails (http://www.linux-archive.org/device-mapper-development/499237-wipe-buffer-even-if-vamlloc-fails.html)

Milan Broz 03-09-2011 03:51 PM

Wipe buffer even if vamlloc fails
 
We can honor secure data flag even when allocation
of local buffer fails but user params is valid.

Signed-off-by: Milan Broz <mbroz@redhat.com>
---
drivers/md/dm-ioctl.c | 13 +++++++++----
1 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 516def2..4cacdad 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1504,6 +1504,7 @@ static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
{
struct dm_ioctl tmp, *dmi;
+ int secure_data;

if (copy_from_user(&tmp, user, sizeof(tmp) - sizeof(tmp.data)))
return -EFAULT;
@@ -1511,23 +1512,27 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data)))
return -EINVAL;

+ secure_data = tmp.flags & DM_SECURE_DATA_FLAG;
+
dmi = vmalloc(tmp.data_size);
- if (!dmi)
+ if (!dmi) {
+ if (secure_data && clear_user(user, tmp.data_size))
+ return -EFAULT;
return -ENOMEM;
+ }

if (copy_from_user(dmi, user, tmp.data_size))
goto bad;

/* Wipe the user buffer so we do not return it to userspace */
- if ((tmp.flags & DM_SECURE_DATA_FLAG) &&
- clear_user(user, tmp.data_size))
+ if (secure_data && clear_user(user, tmp.data_size))
goto bad;

*param = dmi;
return 0;

bad:
- if (tmp.flags & DM_SECURE_DATA_FLAG)
+ if (secure_data)
memset(dmi, 0, tmp.data_size);
vfree(dmi);
return -EFAULT;
--
1.7.2.3

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