xfs: clear kernel only flags in XFS_IOC_ATTRMULTI_BY_HANDLE

Don't allow passing arbitrary flags as they change behavior including
memory allocation that the call stack is not prepared for.

Fixes: ddbca70cc45c ("xfs: allocate xattr buffer on demand")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index 94badfa..91c2cb1 100644 (file)
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -26,7 +26,7 @@ struct xfs_attr_list_context;
  *========================================================================*/
 
 
-#define ATTR_DONTFOLLOW        0x0001  /* -- unused, from IRIX -- */
+#define ATTR_DONTFOLLOW        0x0001  /* -- ignored, from IRIX -- */
 #define ATTR_ROOT      0x0002  /* use attrs in root (trusted) namespace */
 #define ATTR_TRUST     0x0004  /* -- unused, from IRIX -- */
 #define ATTR_SECURE    0x0008  /* use attrs in security namespace */
@@ -37,7 +37,10 @@ struct xfs_attr_list_context;
 #define ATTR_KERNOVAL  0x2000  /* [kernel] get attr size only, not value */
 
 #define ATTR_INCOMPLETE        0x4000  /* [kernel] return INCOMPLETE attr keys */
-#define ATTR_ALLOC     0x8000  /* allocate xattr buffer on demand */
+#define ATTR_ALLOC     0x8000  /* [kernel] allocate xattr buffer on demand */
+
+#define ATTR_KERNEL_FLAGS \
+       (ATTR_KERNOTIME | ATTR_KERNOVAL | ATTR_INCOMPLETE | ATTR_ALLOC)
 
 #define XFS_ATTR_FLAGS \
        { ATTR_DONTFOLLOW,      "DONTFOLLOW" }, \

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 7b35d62..edfbdb8 100644 (file)
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -462,6 +462,8 @@ xfs_attrmulti_by_handle(
 
        error = 0;
        for (i = 0; i < am_hreq.opcount; i++) {
+               ops[i].am_flags &= ~ATTR_KERNEL_FLAGS;
+
                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)

diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index a49bd80..20b3edc 100644 (file)
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -450,6 +450,8 @@ xfs_compat_attrmulti_by_handle(
 
        error = 0;
        for (i = 0; i < am_hreq.opcount; i++) {
+               ops[i].am_flags &= ~ATTR_KERNEL_FLAGS;
+
                ops[i].am_error = strncpy_from_user((char *)attr_name,
                                compat_ptr(ops[i].am_attrname),
                                MAXNAMELEN);