ide: memory overrun in ide_get_identity_ioctl() on big endian machines using ioctl...

This patch fixes a memory overrun in function ide_get_identity_ioctl() which
chooses the size of a memory buffer depending on the ioctl command that led
to the function call, however, passes that buffer to a function which needs the
buffer size to be always chosen unconditionally.

Due to conditional compilation the memory overrun can only happen on big endian
machines. The error can be triggered using ioctl HDIO_OBSOLETE_IDENTITY. Usage
of ioctl HDIO_GET_IDENTITY is safe.

Signed-off-by: Christian Engelmayer <christian.engelmayer@frequentis.com>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/ide/ide-ioctls.c b/drivers/ide/ide-ioctls.c
index 82f252c3ee6e500eb85fc466f1fc26e5c71b6d5a..e246d3d3fbcc5c280ff520b090c297eb42c05a1e 100644 (file)
--- a/drivers/ide/ide-ioctls.c
+++ b/drivers/ide/ide-ioctls.c
@@ -64,7 +64,8 @@ static int ide_get_identity_ioctl(ide_drive_t *drive, unsigned int cmd,
                goto out;
        }
 
-       id = kmalloc(size, GFP_KERNEL);
+       /* ata_id_to_hd_driveid() relies on 'id' to be fully allocated. */
+       id = kmalloc(ATA_ID_WORDS * 2, GFP_KERNEL);
        if (id == NULL) {
                rc = -ENOMEM;
                goto out;