Hi Tuomas,
On 04/21 2014 18:04 PM, Tuomas Tynkkynen wrote:
> xfs_{compat_,}attrmulti_by_handle could return an errno with incorrect
> sign in some cases. While at it, make sure ENOMEM is returned instead of
> E2BIG if kmalloc fails.
>
> Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@xxxxxx>
> ---
> Compile tested only. For the ERANGE case, I also wonder if it should
> be assigning to ops[i].am_error instead of error, and/or have a break.
If I understand right, ops[i].am_error is used to save the internal operation result,
i.e, xfs_attrmult_attr_get{set}... but error is used for the ioctl call results.
Therefore, assign ERANGE to error is compatible with the VFS set{get}xattr syscalls in
case of "if (ops[i].am_error == 0 || ops[i].am_error == MAXNAMELEN)".
It seems that we don't need to have a break in this case because xfs_attrmulti_by_handle()
is used to process multiple attrs. Hence if a given attrname in ops array is invalid,
the am_error will indicate that with ENOATTR or EFAULT...but it should proceed to loop
through the left array members.
Also, looks there is another minor issue at xfs_attrmulti_attr_set(), we should return
-PTR_ERR(kbuf) if call memdup_user() failed.
>
> fs/xfs/xfs_ioctl.c | 5 +++--
> fs/xfs/xfs_ioctl32.c | 5 +++--
> 2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 0b18776..2d8f4fd 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -543,10 +543,11 @@ xfs_attrmulti_by_handle(
>
> ops = memdup_user(am_hreq.ops, size);
> if (IS_ERR(ops)) {
> - error = PTR_ERR(ops);
> + error = -PTR_ERR(ops);
> goto out_dput;
> }
>
> + error = ENOMEM;
> attr_name = kmalloc(MAXNAMELEN, GFP_KERNEL);
> if (!attr_name)
> goto out_kfree_ops;
> @@ -556,7 +557,7 @@ xfs_attrmulti_by_handle(
> ops[i].am_error = strncpy_from_user((char *)attr_name,
> ops[i].am_attrname, MAXNAMELEN);
> if (ops[i].am_error == 0 || ops[i].am_error == MAXNAMELEN)
> - error = -ERANGE;
> + error = ERANGE;
> if (ops[i].am_error < 0)
> break;
>
> diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
> index a7992f8..944d5ba 100644
> --- a/fs/xfs/xfs_ioctl32.c
> +++ b/fs/xfs/xfs_ioctl32.c
> @@ -424,10 +424,11 @@ xfs_compat_attrmulti_by_handle(
>
> ops = memdup_user(compat_ptr(am_hreq.ops), size);
> if (IS_ERR(ops)) {
> - error = PTR_ERR(ops);
> + error = -PTR_ERR(ops);
> goto out_dput;
> }
>
> + error = ENOMEM;
> attr_name = kmalloc(MAXNAMELEN, GFP_KERNEL);
> if (!attr_name)
> goto out_kfree_ops;
> @@ -438,7 +439,7 @@ xfs_compat_attrmulti_by_handle(
> compat_ptr(ops[i].am_attrname),
> MAXNAMELEN);
> if (ops[i].am_error == 0 || ops[i].am_error == MAXNAMELEN)
> - error = -ERANGE;
> + error = ERANGE;
> if (ops[i].am_error < 0)
> break;
>
Thanks,
-Jeff
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