diff mbox

cifs: don't send invalid setxattr requests

Message ID 20170810122143.2o4jln4x6cvz5r2l@mwanda
State New, archived
Headers show

Commit Message

Dan Carpenter Aug. 10, 2017, 12:21 p.m. UTC
There is a static checker warning here because we're taking a "size"
from the user which is in the 1-XATTR_SIZE_MAX range and we're assuming
it's large enough to hold a sizeof(struct cifs_ntsd).  This doesn't
cause a buffer overflow or anything, we just end up sending an invalid
sized command to the server.  The server checks for that in
CIFSSMBGetCIFSACL() and rejects it.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Not tested.  Please review this one carefully.

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Comments

Pavel Shilovsky Aug. 30, 2017, 7:11 p.m. UTC | #1
2017-08-10 5:21 GMT-07:00 Dan Carpenter <dan.carpenter@oracle.com>:
> There is a static checker warning here because we're taking a "size"
> from the user which is in the 1-XATTR_SIZE_MAX range and we're assuming
> it's large enough to hold a sizeof(struct cifs_ntsd).  This doesn't
> cause a buffer overflow or anything, we just end up sending an invalid
> sized command to the server.  The server checks for that in
> CIFSSMBGetCIFSACL() and rejects it.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> Not tested.  Please review this one carefully.
>
> diff --git a/fs/cifs/xattr.c b/fs/cifs/xattr.c
> index de50e749ff05..70bdce5add24 100644
> --- a/fs/cifs/xattr.c
> +++ b/fs/cifs/xattr.c
> @@ -93,6 +93,10 @@ static int cifs_xattr_set(const struct xattr_handler *handler,
>
>                 if (!value)
>                         goto out;
> +               if (size < sizeof(struct cifs_ntsd)) {
> +                       rc = -EINVAL;
> +                       goto out;
> +               }
>                 pacl = kmalloc(size, GFP_KERNEL);
>                 if (!pacl) {
>                         rc = -ENOMEM;
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
> the body of a message to majordomo@vger.kernel.org
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Acked-by: Pavel Shilovsky <pshilov@microsoft.com>

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Best regards,
Pavel Shilovsky
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diff mbox

Patch

diff --git a/fs/cifs/xattr.c b/fs/cifs/xattr.c
index de50e749ff05..70bdce5add24 100644
--- a/fs/cifs/xattr.c
+++ b/fs/cifs/xattr.c
@@ -93,6 +93,10 @@  static int cifs_xattr_set(const struct xattr_handler *handler,
 
 		if (!value)
 			goto out;
+		if (size < sizeof(struct cifs_ntsd)) {
+			rc = -EINVAL;
+			goto out;
+		}
 		pacl = kmalloc(size, GFP_KERNEL);
 		if (!pacl) {
 			rc = -ENOMEM;