debian/patches/CVE-2016-1568-ide-ahci-reset-ncq-object.patch

   1 From 4ab0359a8ae182a7ac5c99609667273167703fab Mon Sep 17 00:00:00 2001
   2 From: Prasad J Pandit <pjp@fedoraproject.org>
   3 Date: Mon, 11 Jan 2016 14:10:42 -0500
   4 Subject: [PATCH] ide: ahci: reset ncq object to unused on error
   5
   6 When processing NCQ commands, AHCI device emulation prepares a
   7 NCQ transfer object; To which an aio control block(aiocb) object
   8 is assigned in 'execute_ncq_command'. In case, when the NCQ
   9 command is invalid, the 'aiocb' object is not assigned, and NCQ
  10 transfer object is left as 'used'. This leads to a use after
  11 free kind of error in 'bdrv_aio_cancel_async' via 'ahci_reset_port'.
  12 Reset NCQ transfer object to 'unused' to avoid it.
  13
  14 [Maintainer edit: s/ACHI/AHCI/ in the commit message. --js]
  15
  16 Reported-by: Qinghao Tang <luodalongde@gmail.com>
  17 Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
  18 Reviewed-by: John Snow <jsnow@redhat.com>
  19 Message-id: 1452282511-4116-1-git-send-email-ppandit@redhat.com
  20 Signed-off-by: John Snow <jsnow@redhat.com>
  21 ---
  22  hw/ide/ahci.c | 1 +
  23  1 file changed, 1 insertion(+)
  24 #     ide_state->error = ABRT_ERR;
  25 #     ide_state->status = READY_STAT | ERR_STAT;
  26 #     ncq_tfs->drive->port_regs.scr_err |= (1 << ncq_tfs->tag);
  27 #+    ncq_tfs->used = 0;
  28 # }
  29 #
  30 # static void ncq_finish(NCQTransferState *ncq_tfs)
  31 --
  32 From Debian:
  33   Mjt:
  34
  35   In 2.1, the code is different.  In particular, execute_ncq_command()
  36   is part of process_ncq_command(), and there's no ncq_err() function
  37   yet.  We do the "used = 0" assignment in the exact place where the
  38   invalid NCQ command is detected.
  39 #         default:
  40 #             DPRINTF(port, "error: tried to process non-NCQ command as NCQ\n");
  41 #             qemu_sglist_destroy(&ncq_tfs->sglist);
  42 #+            ncq_tfs->used = 0;
  43 #             break;
  44 #     }
  45 # }
  46 --
  47   In 2.2 the DPRINTF is split in two:
  48 diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
  49 index dd1912e..17f1cbd 100644
  50 --- a/hw/ide/ahci.c
  51 +++ b/hw/ide/ahci.c
  52 @@ -910,6 +910,7 @@ static void ncq_err(NCQTransferState *ncq_tfs)
  53                          "error: tried to process non-NCQ command as NCQ\n");
  54              }
  55              qemu_sglist_destroy(&ncq_tfs->sglist);
  56 +            ncq_tfs->used = 0;
  57      }
  58  }
  59
  60 --
  61 2.1.4
  62