[PATCH net v2] qed: Fix stack corruption on probe

[PATCH net v2] qed: Fix stack corruption on probe

[Yuval Mintz]

Commit fe56b9e6a8d95 ("qed: Add module with basic common support")
has introduced a stack corruption during probe, where filling a
local struct with data to be sent to management firmware is incorrectly
filled; The data is written outside of the struct and corrupts
the stack.

Changes from v1:
----------------
 - Correct the value written [Caught by David Laight]

Fixes: fe56b9e6a8d95 ("qed: Add module with basic common support")
Signed-off-by: Yuval Mintz <Yuval.Mintz@caviumnetworks.com>
---
Hi Dave,

Please consider applying this to `net'.

Thanks,
Yuval
---
 drivers/net/ethernet/qlogic/qed/qed_mcp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_mcp.c b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
index a240f26..59c81ce 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
@@ -1153,8 +1153,8 @@ qed_mcp_send_drv_version(struct qed_hwfn *p_hwfn,
 	p_drv_version = &union_data.drv_version;
 	p_drv_version->version = p_ver->version;
 
-	for (i = 0; i < MCP_DRV_VER_STR_SIZE - 1; i += 4) {
-		val = cpu_to_be32(p_ver->name[i]);
+	for (i = 0; i < (MCP_DRV_VER_STR_SIZE - 4) / sizeof(u32); i++) {
+		val = cpu_to_be32(*((u32 *)&p_ver->name[i * sizeof(u32)]));
 		*(__be32 *)&p_drv_version->name[i * sizeof(u32)] = val;
 	}
 
-- 
1.9.3

RE: [PATCH net v2] qed: Fix stack corruption on probe

[David Laight]

From: Yuval Mintz 
> Sent: 19 September 2016 15:48
> Commit fe56b9e6a8d95 ("qed: Add module with basic common support")
> has introduced a stack corruption during probe, where filling a
> local struct with data to be sent to management firmware is incorrectly
> filled; The data is written outside of the struct and corrupts
> the stack.
> 
> Changes from v1:
> ----------------
>  - Correct the value written [Caught by David Laight]
> 
> Fixes: fe56b9e6a8d95 ("qed: Add module with basic common support")
> Signed-off-by: Yuval Mintz <Yuval.Mintz@caviumnetworks.com>
> ---
> Hi Dave,
> 
> Please consider applying this to `net'.
> 
> Thanks,
> Yuval
> ---
>  drivers/net/ethernet/qlogic/qed/qed_mcp.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/qlogic/qed/qed_mcp.c b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
> index a240f26..59c81ce 100644
> --- a/drivers/net/ethernet/qlogic/qed/qed_mcp.c
> +++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
> @@ -1153,8 +1153,8 @@ qed_mcp_send_drv_version(struct qed_hwfn *p_hwfn,
>  	p_drv_version = &union_data.drv_version;
>  	p_drv_version->version = p_ver->version;
> 
> -	for (i = 0; i < MCP_DRV_VER_STR_SIZE - 1; i += 4) {
> -		val = cpu_to_be32(p_ver->name[i]);
> +	for (i = 0; i < (MCP_DRV_VER_STR_SIZE - 4) / sizeof(u32); i++) {
> +		val = cpu_to_be32(*((u32 *)&p_ver->name[i * sizeof(u32)]));
>  		*(__be32 *)&p_drv_version->name[i * sizeof(u32)] = val;
>  	}

Or the much simpler:
	/* Byteswap driver name */
	for (i = 0; i < MCP_DRV_VER_STR_SIZE; i++)
		p_drv_version->name[i ^ 3] = p_ver->name[i];

	David

Re: [PATCH net v2] qed: Fix stack corruption on probe

[Mintz, Yuval]

> > Commit fe56b9e6a8d95 ("qed: Add module with basic common support")
> > has introduced a stack corruption during probe, where filling a
> > local struct with data to be sent to management firmware is incorrectly
> > filled; The data is written outside of the struct and corrupts
> > the stack.
> > 
> > @@ -1153,8 +1153,8 @@ qed_mcp_send_drv_version(struct qed_hwfn *p_hwfn,
> >        p_drv_version = &union_data.drv_version;
> >        p_drv_version->version = p_ver->version;
> > 
> > -     for (i = 0; i < MCP_DRV_VER_STR_SIZE - 1; i += 4) {
> > -             val = cpu_to_be32(p_ver->name[i]);
> > +     for (i = 0; i < (MCP_DRV_VER_STR_SIZE - 4) / sizeof(u32); i++) {
> > +             val = cpu_to_be32(*((u32 *)&p_ver->name[i * sizeof(u32)]));
> >                *(__be32 *)&p_drv_version->name[i * sizeof(u32)] = val;
> >        }
> 
> Or the much simpler:
>      /* Byteswap driver name */
>         for (i = 0; i < MCP_DRV_VER_STR_SIZE; i++)
>                 p_drv_version->name[i ^ 3] = p_ver->name[i];

You're suggesting an unconditional swap; This will break
the message on a big endian machine [we'll swap needlessly].
    

Re: [PATCH net v2] qed: Fix stack corruption on probe

[David Miller]

From: Yuval Mintz <Yuval.Mintz@qlogic.com>
Date: Mon, 19 Sep 2016 17:47:41 +0300

> Commit fe56b9e6a8d95 ("qed: Add module with basic common support")
> has introduced a stack corruption during probe, where filling a
> local struct with data to be sent to management firmware is incorrectly
> filled; The data is written outside of the struct and corrupts
> the stack.
> 
> Changes from v1:
> ----------------
>  - Correct the value written [Caught by David Laight]
> 
> Fixes: fe56b9e6a8d95 ("qed: Add module with basic common support")
> Signed-off-by: Yuval Mintz <Yuval.Mintz@caviumnetworks.com>

Applied, thanks.