[PATCH] drm/i915/gvt: Fix the validation on size field of dp aux header
Zhenyu Wang
zhenyuw at linux.intel.com
Wed Apr 11 06:22:01 UTC 2018
Fixes line pls.
On 2018.04.10 13:02:30 +0800, changbin.du at intel.com wrote:
> From: Changbin Du <changbin.du at intel.com>
>
> The assertion for len is wrong, so fix it. And for where to validate
> user input, we should not warn by call trace.
>
> [ 290.584739] WARNING: CPU: 0 PID: 1471 at drivers/gpu/drm/i915/gvt/handlers.c:969 dp_aux_ch_ctl_mmio_write+0x394/0x430 [i915]
> [ 290.586113] task: ffff880111fe8000 task.stack: ffffc90044a9c000
> [ 290.586192] RIP: e030:dp_aux_ch_ctl_mmio_write+0x394/0x430 [i915]
> [ 290.586258] RSP: e02b:ffffc90044a9fd88 EFLAGS: 00010282
> [ 290.586315] RAX: 0000000000000017 RBX: 0000000000000003 RCX: ffffffff82461148
> [ 290.586391] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000201
> [ 290.586468] RBP: ffffc90043ed1000 R08: 0000000000000248 R09: 00000000000003d8
> [ 290.586544] R10: ffffc90044bdd314 R11: 0000000000000011 R12: 0000000000064310
> [ 290.586621] R13: 00000000fe4003ff R14: ffffc900432d1008 R15: ffff88010fa7cb40
> [ 290.586701] FS: 0000000000000000(0000) GS:ffff880123200000(0000) knlGS:0000000000000000
> [ 290.586787] CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 290.586849] CR2: 00007f67ea44e000 CR3: 0000000116078000 CR4: 0000000000042660
> [ 290.586926] Call Trace:
> [ 290.586958] ? __switch_to_asm+0x40/0x70
> [ 290.587017] intel_vgpu_mmio_reg_rw+0x1ec/0x3c0 [i915]
> [ 290.587087] intel_vgpu_emulate_mmio_write+0xa8/0x2c0 [i915]
> [ 290.587151] xengt_emulation_thread+0x501/0x7a0 [xengt]
> [ 290.587208] ? __schedule+0x3c6/0x890
> [ 290.587250] ? wait_woken+0x80/0x80
> [ 290.587290] kthread+0xfc/0x130
> [ 290.587326] ? xengt_gpa_to_va+0x1f0/0x1f0 [xengt]
> [ 290.587378] ? kthread_create_on_node+0x70/0x70
> [ 290.587429] ? do_group_exit+0x3a/0xa0
> [ 290.587471] ret_from_fork+0x35/0x40
>
> Signed-off-by: Changbin Du <changbin.du at intel.com>
> ---
> drivers/gpu/drm/i915/gvt/display.h | 2 +-
> drivers/gpu/drm/i915/gvt/handlers.c | 13 +++++++++----
> 2 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gvt/display.h b/drivers/gpu/drm/i915/gvt/display.h
> index b46b868..ea7c1c5 100644
> --- a/drivers/gpu/drm/i915/gvt/display.h
> +++ b/drivers/gpu/drm/i915/gvt/display.h
> @@ -67,7 +67,7 @@
> #define AUX_NATIVE_REPLY_NAK (0x1 << 4)
> #define AUX_NATIVE_REPLY_DEFER (0x2 << 4)
>
> -#define AUX_BURST_SIZE 16
> +#define AUX_BURST_SIZE 20
>
> /* DPCD addresses */
> #define DPCD_REV 0x000
> diff --git a/drivers/gpu/drm/i915/gvt/handlers.c b/drivers/gpu/drm/i915/gvt/handlers.c
> index a33c1c3e..b77adcc 100644
> --- a/drivers/gpu/drm/i915/gvt/handlers.c
> +++ b/drivers/gpu/drm/i915/gvt/handlers.c
> @@ -900,11 +900,14 @@ static int dp_aux_ch_ctl_mmio_write(struct intel_vgpu *vgpu,
> }
>
> /*
> - * Write request format: (command + address) occupies
> - * 3 bytes, followed by (len + 1) bytes of data.
> + * Write request format: Headr (command + address + size) occupies
> + * 4 bytes, followed by (len + 1) bytes of data. See details at
> + * intel_dp_aux_transfer().
> */
> - if (WARN_ON((len + 4) > AUX_BURST_SIZE))
> + if ((len + 1 + 4) > AUX_BURST_SIZE) {
> + gvt_vgpu_err("dp_aux_header: len %d is too large\n", len);
> return -EINVAL;
> + }
>
> /* unpack data from vreg to buf */
> for (t = 0; t < 4; t++) {
> @@ -968,8 +971,10 @@ static int dp_aux_ch_ctl_mmio_write(struct intel_vgpu *vgpu,
> /*
> * Read reply format: ACK (1 byte) plus (len + 1) bytes of data.
> */
> - if (WARN_ON((len + 2) > AUX_BURST_SIZE))
> + if ((len + 2) > AUX_BURST_SIZE) {
> + gvt_vgpu_err("dp_aux_header: len %d is too large\n", len);
> return -EINVAL;
> + }
>
> /* read from virtual DPCD to vreg */
> /* first 4 bytes: [ACK][addr][addr+1][addr+2] */
> --
> 2.7.4
>
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--
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