[PATCH 2/2] cosa.c : Array index 'i' is used before limits check.

[PATCH 2/2] cosa.c : Array index 'i' is used before limits check.

[Ameen Ali]

avoid out-of-bounds-read by checking count before indexing.

Signed-off-by: Ameen Ali <Ameenali023@gmail.com>
---
 drivers/net/wan/cosa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wan/cosa.c b/drivers/net/wan/cosa.c
index 83c39e2..5252e21 100644
--- a/drivers/net/wan/cosa.c
+++ b/drivers/net/wan/cosa.c
@@ -376,7 +376,7 @@ static int __init cosa_init(void)
 	}
 	for (i=0; i<MAX_CARDS; i++)
 		cosa_cards[i].num = -1;
-	for (i=0; io[i] != 0 && i < MAX_CARDS; i++)
+	for (i=0; (i < MAX_CARDS) && (io[i] != 0) ; i++)
 		cosa_probe(io[i], irq[i], dma[i]);
 	if (!nr_cards) {
 		pr_warn("no devices found\n");
-- 
2.1.0

Re: [PATCH 2/2] cosa.c : Array index 'i' is used before limits check.

[Sergei Shtylyov]

Hello.

On 02/24/2015 10:52 PM, Ameen Ali wrote:

> avoid out-of-bounds-read by checking count before indexing.

> Signed-off-by: Ameen Ali <Ameenali023@gmail.com>
> ---
>   drivers/net/wan/cosa.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

> diff --git a/drivers/net/wan/cosa.c b/drivers/net/wan/cosa.c
> index 83c39e2..5252e21 100644
> --- a/drivers/net/wan/cosa.c
> +++ b/drivers/net/wan/cosa.c
> @@ -376,7 +376,7 @@ static int __init cosa_init(void)
>   	}
>   	for (i=0; i<MAX_CARDS; i++)
>   		cosa_cards[i].num = -1;
> -	for (i=0; io[i] != 0 && i < MAX_CARDS; i++)
> +	for (i=0; (i < MAX_CARDS) && (io[i] != 0) ; i++)

    Parens you've added aren't necessary.
    I suggest to add spaces after and before = in the first expression.

[...]

WBR, Sergei

Re: [PATCH 2/2] cosa.c : Array index 'i' is used before limits check.

[Jan Kasprzak]

Sergei Shtylyov wrote:
: Hello.
: 
: On 02/24/2015 10:52 PM, Ameen Ali wrote:
: 
: >avoid out-of-bounds-read by checking count before indexing.
: 
: >Signed-off-by: Ameen Ali <Ameenali023@gmail.com>
: >---
: >  drivers/net/wan/cosa.c | 2 +-
: >  1 file changed, 1 insertion(+), 1 deletion(-)
: 
: >diff --git a/drivers/net/wan/cosa.c b/drivers/net/wan/cosa.c
: >index 83c39e2..5252e21 100644
: >--- a/drivers/net/wan/cosa.c
: >+++ b/drivers/net/wan/cosa.c
: >@@ -376,7 +376,7 @@ static int __init cosa_init(void)
: >  	}
: >  	for (i=0; i<MAX_CARDS; i++)
: >  		cosa_cards[i].num = -1;
: >-	for (i=0; io[i] != 0 && i < MAX_CARDS; i++)
: >+	for (i=0; (i < MAX_CARDS) && (io[i] != 0) ; i++)
: 
:    Parens you've added aren't necessary.

	Yes, but I am OK with both variants.

:    I suggest to add spaces after and before = in the first expression.

	In that case, also the upper for() cycle should be modified
to match this. I don't think this is necessary.

-Yenya

-- 
| Jan "Yenya" Kasprzak   <kas at {fi.muni.cz - work | yenya.net - private}> |
| New GPG 4096R/A45477D5 -- see http://www.fi.muni.cz/~kas/pgp-rollover.txt |
| http://www.fi.muni.cz/~kas/     Journal: http://www.fi.muni.cz/~kas/blog/ |
||| "New and improved" is only really improved if it also takes backwards |||
||| compatibility into account, rather than saying "now everybody must do |||
||| things the new and improved - and different - way"   --Linus Torvalds |||

Re: [PATCH 2/2] cosa.c : Array index 'i' is used before limits check.

[Sergei Shtylyov]

Hello.

On 3/2/2015 4:06 PM, Jan Kasprzak wrote:

> : >avoid out-of-bounds-read by checking count before indexing.
> :
> : >Signed-off-by: Ameen Ali <Ameenali023@gmail.com>
> : >---
> : >  drivers/net/wan/cosa.c | 2 +-
> : >  1 file changed, 1 insertion(+), 1 deletion(-)
> :
> : >diff --git a/drivers/net/wan/cosa.c b/drivers/net/wan/cosa.c
> : >index 83c39e2..5252e21 100644
> : >--- a/drivers/net/wan/cosa.c
> : >+++ b/drivers/net/wan/cosa.c
> : >@@ -376,7 +376,7 @@ static int __init cosa_init(void)
> : >  	}
> : >  	for (i=0; i<MAX_CARDS; i++)
> : >  		cosa_cards[i].num = -1;
> : >-	for (i=0; io[i] != 0 && i < MAX_CARDS; i++)
> : >+	for (i=0; (i < MAX_CARDS) && (io[i] != 0) ; i++)

> :    Parens you've added aren't necessary.

> 	Yes, but I am OK with both variants.

    Anyway, space before ; should be removed (just noticed).

> :    I suggest to add spaces after and before = in the first expression.

> 	In that case, also the upper for() cycle should be modified
> to match this. I don't think this is necessary.

    As long as it doesn't cause complaints from scripts/checkpatch.pl...

> -Yenya

WBR, Sergei