3.18-stable review patch. If anyone has any objections, please let me know.
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From: Johannes Thumshirn jthumshirn@suse.de
commit f930c7043663188429cd9b254e9d761edfc101ce upstream.
Don't make any assumptions on the sg_io_hdr_t::dxfer_direction or the sg_io_hdr_t::dxferp in order to determine if it is a valid request. The only way we can check for bad requests is by checking if the length exceeds 256M.
Signed-off-by: Johannes Thumshirn jthumshirn@suse.de Fixes: 28676d869bbb (scsi: sg: check for valid direction before starting the request) Reported-by: Jason L Tibbitts III tibbs@math.uh.edu Tested-by: Jason L Tibbitts III tibbs@math.uh.edu Suggested-by: Doug Gilbert dgilbert@interlog.com Cc: Doug Gilbert dgilbert@interlog.com Cc: stable@vger.kernel.org Reviewed-by: Hannes Reinecke hare@suse.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/scsi/sg.c | 32 ++------------------------------ 1 file changed, 2 insertions(+), 30 deletions(-)
--- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -51,6 +51,7 @@ static int sg_version_num = 30536; /* 2 #include <linux/mutex.h> #include <linux/atomic.h> #include <linux/ratelimit.h> +#include <linux/sizes.h>
#include "scsi.h" #include <scsi/scsi_dbg.h> @@ -762,35 +763,6 @@ sg_new_write(Sg_fd *sfp, struct file *fi return count; }
-static bool sg_is_valid_dxfer(sg_io_hdr_t *hp) -{ - switch (hp->dxfer_direction) { - case SG_DXFER_NONE: - if (hp->dxferp || hp->dxfer_len > 0) - return false; - return true; - case SG_DXFER_FROM_DEV: - /* - * for SG_DXFER_FROM_DEV we always set dxfer_len to > 0. dxferp - * can either be NULL or != NULL so there's no point in checking - * it either. So just return true. - */ - return true; - case SG_DXFER_TO_DEV: - case SG_DXFER_TO_FROM_DEV: - if (!hp->dxferp || hp->dxfer_len == 0) - return false; - return true; - case SG_DXFER_UNKNOWN: - if ((!hp->dxferp && hp->dxfer_len) || - (hp->dxferp && hp->dxfer_len == 0)) - return false; - return true; - default: - return false; - } -} - static int sg_common_write(Sg_fd * sfp, Sg_request * srp, unsigned char *cmnd, int timeout, int blocking) @@ -811,7 +783,7 @@ sg_common_write(Sg_fd * sfp, Sg_request "sg_common_write: scsi opcode=0x%02x, cmd_size=%d\n", (int) cmnd[0], (int) hp->cmd_len));
- if (!sg_is_valid_dxfer(hp)) + if (hp->dxfer_len >= SZ_256M) return -EINVAL;
k = sg_start_req(srp, cmnd);