On Sun, May 18, 2008 at 11:22:18AM -0400, Chuck Lever wrote:
> On May 16, 2008, at 3:53 PM, J. Bruce Fields wrote:
>> On Sat, May 10, 2008 at 09:07:23PM -0400, david m. richter wrote:
>>> On Sat, May 10, 2008 at 7:50 PM, Chuck Lever
>>> <chuck.lever@xxxxxxxxxx> wrote:
>>>> On May 10, 2008, at 10:32 AM, Trond Myklebust wrote:
>>>>>
>>>>> On Fri, 2008-05-09 at 19:29 -0700, Chuck Lever wrote:
>>>>>>
>>>>>> Should you use in4_pton() instead?
>>>>>
>>>>> Can we rather convert this to use nfs_parse_server_address? We
>>>>> don't
>>>>> need 10 different ways to parse text addresses...
>>>>
>>>> I'm OK with that, as long as there isn't a technical problem with
>>>> using
>>>> in4_pton().
>>>
>>> nfs_parse_server_address() uses in4_pton(), it just also groks ipv6.
>>
>> This is all a bit orthogonal to the actual bug, as all those functions
>> want null-terminated strings too.
>>
>> We could apply the below (compile-tested only) and then add ipv6
>> support
>> and converting to nfs_parse_server_address() in a subsequent patch.
>
> I'm looking at this code for other reasons, but it would be very easy to
> teach nfs_parse_server_address() to take a string length and not assume
> the passed-in address string is null-terminated. Both in4_pton and
> in6_pton will take a string length.
Whoops, I missed the srclen argument to in4_pton and in6_pton.
Though I just noticed it doesn't really matter much, since the
mountdata.hostname needs a null-terminated string.
--b.
commit 109f9a666db58e0511ac5a417e767027b148a9e0
Author: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
Date: Fri May 9 15:10:56 2008 -0700
nfs: Fix misparsing of nfsv4 fs_locations attribute
The code incorrectly assumes here that the server name (or ip address)
is null-terminated. This can cause referrals to fail in some cases.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 5f9ba41..018292d 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -93,23 +93,6 @@ static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
return 0;
}
-/*
- * Check if the string represents a "valid" IPv4 address
- */
-static inline int valid_ipaddr4(const char *buf)
-{
- int rc, count, in[4];
-
- rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
- if (rc != 4)
- return -EINVAL;
- for (count = 0; count < 4; count++) {
- if (in[count] > 255)
- return -EINVAL;
- }
- return 0;
-}
-
/**
* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
* @mnt_parent - mountpoint of parent directory
@@ -172,19 +155,20 @@ static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
s = 0;
while (s < location->nservers) {
+ const struct nfs4_string *buf = &location->servers[s];
struct sockaddr_in addr = {
.sin_family = AF_INET,
.sin_port = htons(NFS_PORT),
};
+ u8 *ip = (u8 *)addr.sin_addr.s_addr;
- if (location->servers[s].len <= 0 ||
- valid_ipaddr4(location->servers[s].data) < 0) {
- s++;
- continue;
- }
+ if (buf->len <= 0 || buf->len >= PAGE_SIZE)
+ goto next;
+ if (!in4_pton(buf->data, buf->len, ip, '\0', NULL))
+ goto next;
- mountdata.hostname = location->servers[s].data;
- addr.sin_addr.s_addr = in_aton(mountdata.hostname),
+ mountdata.hostname = kmalloc(buf->len + 1, GFP_KERNEL);
+ mountdata.hostname[buf->len] = 0;
mountdata.addr = (struct sockaddr *)&addr;
mountdata.addrlen = sizeof(addr);
@@ -193,9 +177,11 @@ static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
mountdata.mnt_path);
mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, &mountdata);
+ kfree(mountdata.hostname);
if (!IS_ERR(mnt)) {
break;
}
+next:
s++;
}
loc++;
--
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