diff options
| -rw-r--r-- | fs/nfs/super.c | 48 |
1 files changed, 41 insertions, 7 deletions
diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 3bb8318f6d0c..b65001c0a119 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -1607,16 +1607,15 @@ out_security_failure: /* * Select a security flavor for this mount. The selected flavor * is planted in args->auth_flavors[0]. + * + * Returns 0 on success, -EACCES on failure. */ -static void nfs_select_flavor(struct nfs_parsed_mount_data *args, +static int nfs_select_flavor(struct nfs_parsed_mount_data *args, struct nfs_mount_request *request) { unsigned int i, count = *(request->auth_flav_len); rpc_authflavor_t flavor; - if (args->auth_flavors[0] != RPC_AUTH_MAXFLAVOR) - goto out; - /* * The NFSv2 MNT operation does not return a flavor list. */ @@ -1631,6 +1630,25 @@ static void nfs_select_flavor(struct nfs_parsed_mount_data *args, goto out_default; /* + * If the sec= mount option is used, the specified flavor or AUTH_NULL + * must be in the list returned by the server. + * + * AUTH_NULL has a special meaning when it's in the server list - it + * means that the server will ignore the rpc creds, so any flavor + * can be used. + */ + if (args->auth_flavors[0] != RPC_AUTH_MAXFLAVOR) { + for (i = 0; i < count; i++) { + if (args->auth_flavors[0] == request->auth_flavs[i] || + request->auth_flavs[i] == RPC_AUTH_NULL) + goto out; + } + dfprintk(MOUNT, "NFS: auth flavor %d not supported by server\n", + args->auth_flavors[0]); + goto out_err; + } + + /* * RFC 2623, section 2.7 suggests we SHOULD prefer the * flavor listed first. However, some servers list * AUTH_NULL first. Avoid ever choosing AUTH_NULL. @@ -1650,12 +1668,29 @@ static void nfs_select_flavor(struct nfs_parsed_mount_data *args, } } + /* + * As a last chance, see if the server list contains AUTH_NULL - + * if it does, use the default flavor. + */ + for (i = 0; i < count; i++) { + if (request->auth_flavs[i] == RPC_AUTH_NULL) + goto out_default; + } + + dfprintk(MOUNT, "NFS: no auth flavors in common with server\n"); + goto out_err; + out_default: - flavor = RPC_AUTH_UNIX; + /* use default if flavor not already set */ + flavor = (args->auth_flavors[0] == RPC_AUTH_MAXFLAVOR) ? + RPC_AUTH_UNIX : args->auth_flavors[0]; out_set: args->auth_flavors[0] = flavor; out: dfprintk(MOUNT, "NFS: using auth flavor %d\n", args->auth_flavors[0]); + return 0; +out_err: + return -EACCES; } /* @@ -1718,8 +1753,7 @@ static int nfs_request_mount(struct nfs_parsed_mount_data *args, return status; } - nfs_select_flavor(args, &request); - return 0; + return nfs_select_flavor(args, &request); } struct dentry *nfs_try_mount(int flags, const char *dev_name, |