[PATCH] mountd: fix mount issue due to comparison with uninitialized uuid

[PATCH] mountd: fix mount issue due to comparison with uninitialized uuid

[Vivek Trivedi]

fix mount issue due to comparison of uninitialized variable
u(uuid) with parsed->fhuuid when uuid_by_path return 0.

/tmp/usb            192.168.1.0/16(ro,no_root_squash,no_subtree_check,fsid=0)
/tmp/usb/sda1       192.168.1.0/16(ro,no_root_squash,no_subtree_check)
/tmp/usb/sdb1       192.168.1.0/16(ro,no_root_squash,no_subtree_check)

mount -t nfs -o nolock,nfsvers=3 192.168.1.2:/tmp/usb/sda1 /tmp/sda1
mount -t nfs -o nolock,nfsvers=3 192.168.1.2:/tmp/usb/sdb1 /tmp/sdb1

results in below mountd error:
mountd: /tmp/usb and /tmp/usb/sdb1 have same filehandle for 192.168.1.0/16, using first

when uuid_by_path returned 0, by chance, garbage value of u was same as
parsed->fhuuid(of sdb1), and comparison of these resulted in above error.

Signed-off-by: Vivek Trivedi <t.vivek@samsung.com>
Reviewed-by: Amit Sahrawat <a.sahrawat@samsung.com>
---
 utils/mountd/cache.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c
index 7d250f9..7847446 100644
--- a/utils/mountd/cache.c
+++ b/utils/mountd/cache.c
@@ -638,18 +638,17 @@ static bool match_fsid(struct parsed_fsid *parsed, nfs_export *exp, char *path)
 		if (!is_mountpoint(path))
 			return false;
 	check_uuid:
-		if (exp->m_export.e_uuid)
+		if (exp->m_export.e_uuid) {
 			get_uuid(exp->m_export.e_uuid, parsed->uuidlen, u);
+			if (memcmp(u, parsed->fhuuid, parsed->uuidlen) == 0)
+				return true;
+		}
 		else
 			for (type = 0;
 			     uuid_by_path(path, type, parsed->uuidlen, u);
 			     type++)
 				if (memcmp(u, parsed->fhuuid, parsed->uuidlen) == 0)
 					return true;
-
-		if (memcmp(u, parsed->fhuuid, parsed->uuidlen) != 0)
-			return false;
-		return true;
 	}
 	/* Well, unreachable, actually: */
 	return false;
-- 
1.7.9.5

Re: [PATCH] mountd: fix mount issue due to comparison with uninitialized uuid

[Steve Dickson]

On 08/07/2015 08:10 AM, Vivek Trivedi wrote:
> fix mount issue due to comparison of uninitialized variable
> u(uuid) with parsed->fhuuid when uuid_by_path return 0.
> 
> /tmp/usb            192.168.1.0/16(ro,no_root_squash,no_subtree_check,fsid=0)
> /tmp/usb/sda1       192.168.1.0/16(ro,no_root_squash,no_subtree_check)
> /tmp/usb/sdb1       192.168.1.0/16(ro,no_root_squash,no_subtree_check)
> 
> mount -t nfs -o nolock,nfsvers=3 192.168.1.2:/tmp/usb/sda1 /tmp/sda1
> mount -t nfs -o nolock,nfsvers=3 192.168.1.2:/tmp/usb/sdb1 /tmp/sdb1
> 
> results in below mountd error:
> mountd: /tmp/usb and /tmp/usb/sdb1 have same filehandle for 192.168.1.0/16, using first
> 
> when uuid_by_path returned 0, by chance, garbage value of u was same as
> parsed->fhuuid(of sdb1), and comparison of these resulted in above error.
> 
> Signed-off-by: Vivek Trivedi <t.vivek@samsung.com>
> Reviewed-by: Amit Sahrawat <a.sahrawat@samsung.com>
Committed... 

steved.

> ---
>  utils/mountd/cache.c |    9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/utils/mountd/cache.c b/utils/mountd/cache.c
> index 7d250f9..7847446 100644
> --- a/utils/mountd/cache.c
> +++ b/utils/mountd/cache.c
> @@ -638,18 +638,17 @@ static bool match_fsid(struct parsed_fsid *parsed, nfs_export *exp, char *path)
>  		if (!is_mountpoint(path))
>  			return false;
>  	check_uuid:
> -		if (exp->m_export.e_uuid)
> +		if (exp->m_export.e_uuid) {
>  			get_uuid(exp->m_export.e_uuid, parsed->uuidlen, u);
> +			if (memcmp(u, parsed->fhuuid, parsed->uuidlen) == 0)
> +				return true;
> +		}
>  		else
>  			for (type = 0;
>  			     uuid_by_path(path, type, parsed->uuidlen, u);
>  			     type++)
>  				if (memcmp(u, parsed->fhuuid, parsed->uuidlen) == 0)
>  					return true;
> -
> -		if (memcmp(u, parsed->fhuuid, parsed->uuidlen) != 0)
> -			return false;
> -		return true;
>  	}
>  	/* Well, unreachable, actually: */
>  	return false;
>