* [PATCH v2] drivers/net/cxgb3/cxgb3_main.c: prevent reading uninitialized stack memory
@ 2010-09-15 21:43 Dan Rosenberg
2010-09-16 15:54 ` Steven Rostedt
2010-09-17 4:55 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Dan Rosenberg @ 2010-09-15 21:43 UTC (permalink / raw)
To: divy; +Cc: linux-kernel, netdev, security
Fixed formatting (tabs and line breaks).
The CHELSIO_GET_QSET_NUM device ioctl allows unprivileged users to read
4 bytes of uninitialized stack memory, because the "addr" member of the
ch_reg struct declared on the stack in cxgb_extension_ioctl() is not
altered or zeroed before being copied back to the user. This patch
takes care of it.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
--- linux-2.6.35.4.orig/drivers/net/cxgb3/cxgb3_main.c 2010-08-26 19:47:12.000000000 -0400
+++ linux-2.6.35.4/drivers/net/cxgb3/cxgb3_main.c 2010-09-14 21:24:34.369511115 -0400
@@ -2296,6 +2296,8 @@ static int cxgb_extension_ioctl(struct n
case CHELSIO_GET_QSET_NUM:{
struct ch_reg edata;
+ memset(&edata, 0, sizeof(struct ch_reg));
+
edata.cmd = CHELSIO_GET_QSET_NUM;
edata.val = pi->nqsets;
if (copy_to_user(useraddr, &edata, sizeof(edata)))
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] drivers/net/cxgb3/cxgb3_main.c: prevent reading uninitialized stack memory
2010-09-15 21:43 [PATCH v2] drivers/net/cxgb3/cxgb3_main.c: prevent reading uninitialized stack memory Dan Rosenberg
@ 2010-09-16 15:54 ` Steven Rostedt
2010-09-17 4:55 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Steven Rostedt @ 2010-09-16 15:54 UTC (permalink / raw)
To: Dan Rosenberg; +Cc: divy, linux-kernel, netdev, security
On Wed, Sep 15, 2010 at 05:43:12PM -0400, Dan Rosenberg wrote:
> Fixed formatting (tabs and line breaks).
>
> The CHELSIO_GET_QSET_NUM device ioctl allows unprivileged users to read
> 4 bytes of uninitialized stack memory, because the "addr" member of the
> ch_reg struct declared on the stack in cxgb_extension_ioctl() is not
> altered or zeroed before being copied back to the user. This patch
> takes care of it.
>
> Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
>
> --- linux-2.6.35.4.orig/drivers/net/cxgb3/cxgb3_main.c 2010-08-26 19:47:12.000000000 -0400
> +++ linux-2.6.35.4/drivers/net/cxgb3/cxgb3_main.c 2010-09-14 21:24:34.369511115 -0400
> @@ -2296,6 +2296,8 @@ static int cxgb_extension_ioctl(struct n
> case CHELSIO_GET_QSET_NUM:{
> struct ch_reg edata;
>
> + memset(&edata, 0, sizeof(struct ch_reg));
> +
> edata.cmd = CHELSIO_GET_QSET_NUM;
> edata.val = pi->nqsets;
This is a pretty expensive way to fix it. either...
+ edata.addr = 0;
or:
- struct ch_reg edata;
+ struct ch_reg edata = {
+ .cmd = CHELSIO_GET_QSET_NUM,
+ .val = pi->nqsets
+ };
- edata.cmd = CHELSIO_GET_QSET_NUM;
- edata.val = pi->nqsets;
If you are worried that the struct ch_reg may grow someday.
-- Steve
> if (copy_to_user(useraddr, &edata, sizeof(edata)))
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] drivers/net/cxgb3/cxgb3_main.c: prevent reading uninitialized stack memory
2010-09-15 21:43 [PATCH v2] drivers/net/cxgb3/cxgb3_main.c: prevent reading uninitialized stack memory Dan Rosenberg
2010-09-16 15:54 ` Steven Rostedt
@ 2010-09-17 4:55 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2010-09-17 4:55 UTC (permalink / raw)
To: drosenberg; +Cc: divy, linux-kernel, netdev, security
From: Dan Rosenberg <drosenberg@vsecurity.com>
Date: Wed, 15 Sep 2010 17:43:12 -0400
> Fixed formatting (tabs and line breaks).
>
> The CHELSIO_GET_QSET_NUM device ioctl allows unprivileged users to read
> 4 bytes of uninitialized stack memory, because the "addr" member of the
> ch_reg struct declared on the stack in cxgb_extension_ioctl() is not
> altered or zeroed before being copied back to the user. This patch
> takes care of it.
>
> Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Applied.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-09-15 21:43 [PATCH v2] drivers/net/cxgb3/cxgb3_main.c: prevent reading uninitialized stack memory Dan Rosenberg
2010-09-16 15:54 ` Steven Rostedt
2010-09-17 4:55 ` David Miller
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