[PATCH 3.10 135/250] ocfs2: do not write error flag to user structure we cannot copy from/to

From: Willy Tarreau
Date: Wed Jun 07 2017 - 19:15:28 EST


From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>

commit 2b462638e41ea62230297c21c4da9955937b7a3c upstream.

If we failed to copy from the structure, writing back the flags leaks 31
bits of kernel memory (the rest of the ir_flags field).

In any case, if we cannot copy from/to the structure, why should we
expect putting just the flags to work?

Also make sure ocfs2_info_handle_freeinode() returns the right error
code if the copy_to_user() fails.

Fixes: ddee5cdb70e6 ('Ocfs2: Add new OCFS2_IOC_INFO ioctl for ocfs2 v8.')
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Acked-by: Mark Fasheh <mfasheh@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
fs/ocfs2/ioctl.c | 129 +++++++++++++++++++------------------------------------
1 file changed, 43 insertions(+), 86 deletions(-)

diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index 0c60ef2..b9d1609 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -34,9 +34,8 @@
copy_to_user((typeof(a) __user *)b, &(a), sizeof(a))

/*
- * This call is void because we are already reporting an error that may
- * be -EFAULT. The error will be returned from the ioctl(2) call. It's
- * just a best-effort to tell userspace that this request caused the error.
+ * This is just a best-effort to tell userspace that this request
+ * caused the error.
*/
static inline void o2info_set_request_error(struct ocfs2_info_request *kreq,
struct ocfs2_info_request __user *req)
@@ -145,136 +144,105 @@ bail:
int ocfs2_info_handle_blocksize(struct inode *inode,
struct ocfs2_info_request __user *req)
{
- int status = -EFAULT;
struct ocfs2_info_blocksize oib;

if (o2info_from_user(oib, req))
- goto bail;
+ return -EFAULT;

oib.ib_blocksize = inode->i_sb->s_blocksize;

o2info_set_request_filled(&oib.ib_req);

if (o2info_to_user(oib, req))
- goto bail;
-
- status = 0;
-bail:
- if (status)
- o2info_set_request_error(&oib.ib_req, req);
+ return -EFAULT;

- return status;
+ return 0;
}

int ocfs2_info_handle_clustersize(struct inode *inode,
struct ocfs2_info_request __user *req)
{
- int status = -EFAULT;
struct ocfs2_info_clustersize oic;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

if (o2info_from_user(oic, req))
- goto bail;
+ return -EFAULT;

oic.ic_clustersize = osb->s_clustersize;

o2info_set_request_filled(&oic.ic_req);

if (o2info_to_user(oic, req))
- goto bail;
-
- status = 0;
-bail:
- if (status)
- o2info_set_request_error(&oic.ic_req, req);
+ return -EFAULT;

- return status;
+ return 0;
}

int ocfs2_info_handle_maxslots(struct inode *inode,
struct ocfs2_info_request __user *req)
{
- int status = -EFAULT;
struct ocfs2_info_maxslots oim;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

if (o2info_from_user(oim, req))
- goto bail;
+ return -EFAULT;

oim.im_max_slots = osb->max_slots;

o2info_set_request_filled(&oim.im_req);

if (o2info_to_user(oim, req))
- goto bail;
+ return -EFAULT;

- status = 0;
-bail:
- if (status)
- o2info_set_request_error(&oim.im_req, req);
-
- return status;
+ return 0;
}

int ocfs2_info_handle_label(struct inode *inode,
struct ocfs2_info_request __user *req)
{
- int status = -EFAULT;
struct ocfs2_info_label oil;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

if (o2info_from_user(oil, req))
- goto bail;
+ return -EFAULT;

memcpy(oil.il_label, osb->vol_label, OCFS2_MAX_VOL_LABEL_LEN);

o2info_set_request_filled(&oil.il_req);

if (o2info_to_user(oil, req))
- goto bail;
+ return -EFAULT;

- status = 0;
-bail:
- if (status)
- o2info_set_request_error(&oil.il_req, req);
-
- return status;
+ return 0;
}

int ocfs2_info_handle_uuid(struct inode *inode,
struct ocfs2_info_request __user *req)
{
- int status = -EFAULT;
struct ocfs2_info_uuid oiu;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

if (o2info_from_user(oiu, req))
- goto bail;
+ return -EFAULT;

memcpy(oiu.iu_uuid_str, osb->uuid_str, OCFS2_TEXT_UUID_LEN + 1);

o2info_set_request_filled(&oiu.iu_req);

if (o2info_to_user(oiu, req))
- goto bail;
-
- status = 0;
-bail:
- if (status)
- o2info_set_request_error(&oiu.iu_req, req);
+ return -EFAULT;

- return status;
+ return 0;
}

int ocfs2_info_handle_fs_features(struct inode *inode,
struct ocfs2_info_request __user *req)
{
- int status = -EFAULT;
struct ocfs2_info_fs_features oif;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

if (o2info_from_user(oif, req))
- goto bail;
+ return -EFAULT;

oif.if_compat_features = osb->s_feature_compat;
oif.if_incompat_features = osb->s_feature_incompat;
@@ -283,39 +251,28 @@ int ocfs2_info_handle_fs_features(struct inode *inode,
o2info_set_request_filled(&oif.if_req);

if (o2info_to_user(oif, req))
- goto bail;
+ return -EFAULT;

- status = 0;
-bail:
- if (status)
- o2info_set_request_error(&oif.if_req, req);
-
- return status;
+ return 0;
}

int ocfs2_info_handle_journal_size(struct inode *inode,
struct ocfs2_info_request __user *req)
{
- int status = -EFAULT;
struct ocfs2_info_journal_size oij;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

if (o2info_from_user(oij, req))
- goto bail;
+ return -EFAULT;

oij.ij_journal_size = osb->journal->j_inode->i_size;

o2info_set_request_filled(&oij.ij_req);

if (o2info_to_user(oij, req))
- goto bail;
+ return -EFAULT;

- status = 0;
-bail:
- if (status)
- o2info_set_request_error(&oij.ij_req, req);
-
- return status;
+ return 0;
}

int ocfs2_info_scan_inode_alloc(struct ocfs2_super *osb,
@@ -371,7 +328,7 @@ int ocfs2_info_handle_freeinode(struct inode *inode,
u32 i;
u64 blkno = -1;
char namebuf[40];
- int status = -EFAULT, type = INODE_ALLOC_SYSTEM_INODE;
+ int status, type = INODE_ALLOC_SYSTEM_INODE;
struct ocfs2_info_freeinode *oifi = NULL;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
struct inode *inode_alloc = NULL;
@@ -383,8 +340,10 @@ int ocfs2_info_handle_freeinode(struct inode *inode,
goto out_err;
}

- if (o2info_from_user(*oifi, req))
- goto bail;
+ if (o2info_from_user(*oifi, req)) {
+ status = -EFAULT;
+ goto out_free;
+ }

oifi->ifi_slotnum = osb->max_slots;

@@ -421,14 +380,16 @@ int ocfs2_info_handle_freeinode(struct inode *inode,

o2info_set_request_filled(&oifi->ifi_req);

- if (o2info_to_user(*oifi, req))
- goto bail;
+ if (o2info_to_user(*oifi, req)) {
+ status = -EFAULT;
+ goto out_free;
+ }

status = 0;
bail:
if (status)
o2info_set_request_error(&oifi->ifi_req, req);
-
+out_free:
kfree(oifi);
out_err:
return status;
@@ -655,7 +616,7 @@ int ocfs2_info_handle_freefrag(struct inode *inode,
{
u64 blkno = -1;
char namebuf[40];
- int status = -EFAULT, type = GLOBAL_BITMAP_SYSTEM_INODE;
+ int status, type = GLOBAL_BITMAP_SYSTEM_INODE;

struct ocfs2_info_freefrag *oiff;
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
@@ -668,8 +629,10 @@ int ocfs2_info_handle_freefrag(struct inode *inode,
goto out_err;
}

- if (o2info_from_user(*oiff, req))
- goto bail;
+ if (o2info_from_user(*oiff, req)) {
+ status = -EFAULT;
+ goto out_free;
+ }
/*
* chunksize from userspace should be power of 2.
*/
@@ -708,14 +671,14 @@ int ocfs2_info_handle_freefrag(struct inode *inode,

if (o2info_to_user(*oiff, req)) {
status = -EFAULT;
- goto bail;
+ goto out_free;
}

status = 0;
bail:
if (status)
o2info_set_request_error(&oiff->iff_req, req);
-
+out_free:
kfree(oiff);
out_err:
return status;
@@ -724,23 +687,17 @@ out_err:
int ocfs2_info_handle_unknown(struct inode *inode,
struct ocfs2_info_request __user *req)
{
- int status = -EFAULT;
struct ocfs2_info_request oir;

if (o2info_from_user(oir, req))
- goto bail;
+ return -EFAULT;

o2info_clear_request_filled(&oir);

if (o2info_to_user(oir, req))
- goto bail;
+ return -EFAULT;

- status = 0;
-bail:
- if (status)
- o2info_set_request_error(&oir, req);
-
- return status;
+ return 0;
}

/*
--
2.8.0.rc2.1.gbe9624a