diff mbox

[v2] sunrpc: integer underflow in rsc_parse()

Message ID 20150224153401.GA12218@mwanda (mailing list archive)
State New, archived
Headers show

Commit Message

Dan Carpenter Feb. 24, 2015, 3:34 p.m. UTC
If we call groups_alloc() with invalid values then it's might lead to
memory corruption.  For example, with a negative value then we might not
allocate enough for sizeof(struct group_info).

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2:  In v1, I changed groups_alloc().  The other places which call
groups_alloc() check the value before calling.  Eric wanted that, either
have all the callers check, or all the callers rely on groups_alloc().
In the end, Bruce Fields said adding the check here was probably
reasonable.

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Comments

Simo Sorce Feb. 25, 2015, 3:54 a.m. UTC | #1
On Tue, 2015-02-24 at 18:34 +0300, Dan Carpenter wrote:
> If we call groups_alloc() with invalid values then it's might lead to
> memory corruption.  For example, with a negative value then we might not
> allocate enough for sizeof(struct group_info).
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2:  In v1, I changed groups_alloc().  The other places which call
> groups_alloc() check the value before calling.  Eric wanted that, either
> have all the callers check, or all the callers rely on groups_alloc().
> In the end, Bruce Fields said adding the check here was probably
> reasonable.
> 
> diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
> index 224a82f..1095be9 100644
> --- a/net/sunrpc/auth_gss/svcauth_gss.c
> +++ b/net/sunrpc/auth_gss/svcauth_gss.c
> @@ -463,6 +463,8 @@ static int rsc_parse(struct cache_detail *cd,
>  		/* number of additional gid's */
>  		if (get_int(&mesg, &N))
>  			goto out;
> +		if (N < 0 || N > NGROUPS_MAX)
> +			goto out;
>  		status = -ENOMEM;
>  		rsci.cred.cr_group_info = groups_alloc(N);
>  		if (rsci.cred.cr_group_info == NULL)
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
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I touched this code relatively recently, and this check looks correct.
Feel free to add Reviewed-by: Simo Sorce <simo@redhat.com>

Simo.
diff mbox

Patch

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 224a82f..1095be9 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -463,6 +463,8 @@  static int rsc_parse(struct cache_detail *cd,
 		/* number of additional gid's */
 		if (get_int(&mesg, &N))
 			goto out;
+		if (N < 0 || N > NGROUPS_MAX)
+			goto out;
 		status = -ENOMEM;
 		rsci.cred.cr_group_info = groups_alloc(N);
 		if (rsci.cred.cr_group_info == NULL)