diff options
author | Chuck Lever <chuck.lever@oracle.com> | 2010-12-14 14:57:12 +0000 |
---|---|---|
committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2010-12-16 12:37:23 -0500 |
commit | 3460f29a27344db8c7af62cafdb961286ef0b6cd (patch) | |
tree | be7c8acc0c8c971114f8136534c613395a4d2951 /fs/lockd/clnt4xdr.c | |
parent | f6048709391336cf27fb5c1cfca8e792103e5a73 (diff) |
lockd: Introduce new-style XDR functions for NLMv4
We'd like to prevent local buffer overflows caused by malicious or
broken servers. New xdr_stream style decoders can do that.
For efficiency, we also want to be able to pass xdr_streams from
call_encode() to all XDR encoding functions, rather than building
an xdr_stream in every XDR encoding function in the kernel.
Same idea as the NLM v3 XDR overhaul.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/lockd/clnt4xdr.c')
-rw-r--r-- | fs/lockd/clnt4xdr.c | 621 |
1 files changed, 621 insertions, 0 deletions
diff --git a/fs/lockd/clnt4xdr.c b/fs/lockd/clnt4xdr.c new file mode 100644 index 00000000000..1a1c3e21ed2 --- /dev/null +++ b/fs/lockd/clnt4xdr.c @@ -0,0 +1,621 @@ +/* + * linux/fs/lockd/clnt4xdr.c + * + * XDR functions to encode/decode NLM version 4 RPC arguments and results. + * + * NLM client-side only. + * + * Copyright (C) 2010, Oracle. All rights reserved. + */ + +#include <linux/types.h> +#include <linux/sunrpc/xdr.h> +#include <linux/sunrpc/clnt.h> +#include <linux/sunrpc/stats.h> +#include <linux/lockd/lockd.h> + +#define NLMDBG_FACILITY NLMDBG_XDR + +#if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ) +# error "NLM host name cannot be larger than XDR_MAX_NETOBJ!" +#endif + +#if (NLMCLNT_OHSIZE > NLM_MAXSTRLEN) +# error "NLM host name cannot be larger than NLM's maximum string length!" +#endif + +/* + * Declare the space requirements for NLM arguments and replies as + * number of 32bit-words + */ +#define NLM4_void_sz (0) +#define NLM4_cookie_sz (1+(NLM_MAXCOOKIELEN>>2)) +#define NLM4_caller_sz (1+(NLMCLNT_OHSIZE>>2)) +#define NLM4_owner_sz (1+(NLMCLNT_OHSIZE>>2)) +#define NLM4_fhandle_sz (1+(NFS3_FHSIZE>>2)) +#define NLM4_lock_sz (5+NLM4_caller_sz+NLM4_owner_sz+NLM4_fhandle_sz) +#define NLM4_holder_sz (6+NLM4_owner_sz) + +#define NLM4_testargs_sz (NLM4_cookie_sz+1+NLM4_lock_sz) +#define NLM4_lockargs_sz (NLM4_cookie_sz+4+NLM4_lock_sz) +#define NLM4_cancargs_sz (NLM4_cookie_sz+2+NLM4_lock_sz) +#define NLM4_unlockargs_sz (NLM4_cookie_sz+NLM4_lock_sz) + +#define NLM4_testres_sz (NLM4_cookie_sz+1+NLM4_holder_sz) +#define NLM4_res_sz (NLM4_cookie_sz+1) +#define NLM4_norep_sz (0) + + +static s64 loff_t_to_s64(loff_t offset) +{ + s64 res; + + if (offset >= NLM4_OFFSET_MAX) + res = NLM4_OFFSET_MAX; + else if (offset <= -NLM4_OFFSET_MAX) + res = -NLM4_OFFSET_MAX; + else + res = offset; + return res; +} + +static void nlm4_compute_offsets(const struct nlm_lock *lock, + u64 *l_offset, u64 *l_len) +{ + const struct file_lock *fl = &lock->fl; + + BUG_ON(fl->fl_start > NLM4_OFFSET_MAX); + BUG_ON(fl->fl_end > NLM4_OFFSET_MAX && + fl->fl_end != OFFSET_MAX); + + *l_offset = loff_t_to_s64(fl->fl_start); + if (fl->fl_end == OFFSET_MAX) + *l_len = 0; + else + *l_len = loff_t_to_s64(fl->fl_end - fl->fl_start + 1); +} + +/* + * Handle decode buffer overflows out-of-line. + */ +static void print_overflow_msg(const char *func, const struct xdr_stream *xdr) +{ + dprintk("lockd: %s prematurely hit the end of our receive buffer. " + "Remaining buffer length is %tu words.\n", + func, xdr->end - xdr->p); +} + + +/* + * Encode/decode NLMv4 basic data types + * + * Basic NLMv4 data types are defined in Appendix II, section 6.1.4 + * of RFC 1813: "NFS Version 3 Protocol Specification" and in Chapter + * 10 of X/Open's "Protocols for Interworking: XNFS, Version 3W". + * + * Not all basic data types have their own encoding and decoding + * functions. For run-time efficiency, some data types are encoded + * or decoded inline. + */ + +static void encode_bool(struct xdr_stream *xdr, const int value) +{ + __be32 *p; + + p = xdr_reserve_space(xdr, 4); + *p = value ? xdr_one : xdr_zero; +} + +static void encode_int32(struct xdr_stream *xdr, const s32 value) +{ + __be32 *p; + + p = xdr_reserve_space(xdr, 4); + *p = cpu_to_be32(value); +} + +/* + * typedef opaque netobj<MAXNETOBJ_SZ> + */ +static void encode_netobj(struct xdr_stream *xdr, + const u8 *data, const unsigned int length) +{ + __be32 *p; + + BUG_ON(length > XDR_MAX_NETOBJ); + p = xdr_reserve_space(xdr, 4 + length); + xdr_encode_opaque(p, data, length); +} + +static int decode_netobj(struct xdr_stream *xdr, + struct xdr_netobj *obj) +{ + u32 length; + __be32 *p; + + p = xdr_inline_decode(xdr, 4); + if (unlikely(p == NULL)) + goto out_overflow; + length = be32_to_cpup(p++); + if (unlikely(length > XDR_MAX_NETOBJ)) + goto out_size; + obj->len = length; + obj->data = (u8 *)p; + return 0; +out_size: + dprintk("NFS: returned netobj was too long: %u\n", length); + return -EIO; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + +/* + * netobj cookie; + */ +static void encode_cookie(struct xdr_stream *xdr, + const struct nlm_cookie *cookie) +{ + BUG_ON(cookie->len > NLM_MAXCOOKIELEN); + encode_netobj(xdr, (u8 *)&cookie->data, cookie->len); +} + +static int decode_cookie(struct xdr_stream *xdr, + struct nlm_cookie *cookie) +{ + u32 length; + __be32 *p; + + p = xdr_inline_decode(xdr, 4); + if (unlikely(p == NULL)) + goto out_overflow; + length = be32_to_cpup(p++); + /* apparently HPUX can return empty cookies */ + if (length == 0) + goto out_hpux; + if (length > NLM_MAXCOOKIELEN) + goto out_size; + p = xdr_inline_decode(xdr, length); + if (unlikely(p == NULL)) + goto out_overflow; + cookie->len = length; + memcpy(cookie->data, p, length); + return 0; +out_hpux: + cookie->len = 4; + memset(cookie->data, 0, 4); + return 0; +out_size: + dprintk("NFS: returned cookie was too long: %u\n", length); + return -EIO; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + +/* + * netobj fh; + */ +static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh) +{ + BUG_ON(fh->size > NFS3_FHSIZE); + encode_netobj(xdr, (u8 *)&fh->data, fh->size); +} + +/* + * enum nlm4_stats { + * NLM4_GRANTED = 0, + * NLM4_DENIED = 1, + * NLM4_DENIED_NOLOCKS = 2, + * NLM4_BLOCKED = 3, + * NLM4_DENIED_GRACE_PERIOD = 4, + * NLM4_DEADLCK = 5, + * NLM4_ROFS = 6, + * NLM4_STALE_FH = 7, + * NLM4_FBIG = 8, + * NLM4_FAILED = 9 + * }; + * + * struct nlm4_stat { + * nlm4_stats stat; + * }; + * + * NB: we don't swap bytes for the NLM status values. The upper + * layers deal directly with the status value in network byte + * order. + */ +static void encode_nlm4_stat(struct xdr_stream *xdr, + const __be32 stat) +{ + __be32 *p; + + BUG_ON(be32_to_cpu(stat) > NLM_FAILED); + p = xdr_reserve_space(xdr, 4); + *p = stat; +} + +static int decode_nlm4_stat(struct xdr_stream *xdr, __be32 *stat) +{ + __be32 *p; + + p = xdr_inline_decode(xdr, 4); + if (unlikely(p == NULL)) + goto out_overflow; + if (unlikely(*p > nlm4_failed)) + goto out_bad_xdr; + *stat = *p; + return 0; +out_bad_xdr: + dprintk("%s: server returned invalid nlm4_stats value: %u\n", + __func__, be32_to_cpup(p)); + return -EIO; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + +/* + * struct nlm4_holder { + * bool exclusive; + * int32 svid; + * netobj oh; + * uint64 l_offset; + * uint64 l_len; + * }; + */ +static void encode_nlm4_holder(struct xdr_stream *xdr, + const struct nlm_res *result) +{ + const struct nlm_lock *lock = &result->lock; + u64 l_offset, l_len; + __be32 *p; + + encode_bool(xdr, lock->fl.fl_type == F_RDLCK); + encode_int32(xdr, lock->svid); + encode_netobj(xdr, lock->oh.data, lock->oh.len); + + p = xdr_reserve_space(xdr, 4 + 4); + nlm4_compute_offsets(lock, &l_offset, &l_len); + p = xdr_encode_hyper(p, l_offset); + xdr_encode_hyper(p, l_len); +} + +static int decode_nlm4_holder(struct xdr_stream *xdr, struct nlm_res *result) +{ + struct nlm_lock *lock = &result->lock; + struct file_lock *fl = &lock->fl; + u64 l_offset, l_len; + u32 exclusive; + int error; + __be32 *p; + s32 end; + + memset(lock, 0, sizeof(*lock)); + locks_init_lock(fl); + + p = xdr_inline_decode(xdr, 4 + 4); + if (unlikely(p == NULL)) + goto out_overflow; + exclusive = be32_to_cpup(p++); + lock->svid = be32_to_cpup(p); + fl->fl_pid = (pid_t)lock->svid; + + error = decode_netobj(xdr, &lock->oh); + if (unlikely(error)) + goto out; + + p = xdr_inline_decode(xdr, 8 + 8); + if (unlikely(p == NULL)) + goto out_overflow; + + fl->fl_flags = FL_POSIX; + fl->fl_type = exclusive != 0 ? F_WRLCK : F_RDLCK; + p = xdr_decode_hyper(p, &l_offset); + xdr_decode_hyper(p, &l_len); + end = l_offset + l_len - 1; + + fl->fl_start = (loff_t)l_offset; + if (l_len == 0 || end < 0) + fl->fl_end = OFFSET_MAX; + else + fl->fl_end = (loff_t)end; + error = 0; +out: + return error; +out_overflow: + print_overflow_msg(__func__, xdr); + return -EIO; +} + +/* + * string caller_name<LM_MAXSTRLEN>; + */ +static void encode_caller_name(struct xdr_stream *xdr, const char *name) +{ + /* NB: client-side does not set lock->len */ + u32 length = strlen(name); + __be32 *p; + + BUG_ON(length > NLM_MAXSTRLEN); + p = xdr_reserve_space(xdr, 4 + length); + xdr_encode_opaque(p, name, length); +} + +/* + * struct nlm4_lock { + * string caller_name<LM_MAXSTRLEN>; + * netobj fh; + * netobj oh; + * int32 svid; + * uint64 l_offset; + * uint64 l_len; + * }; + */ +static void encode_nlm4_lock(struct xdr_stream *xdr, + const struct nlm_lock *lock) +{ + u64 l_offset, l_len; + __be32 *p; + + encode_caller_name(xdr, lock->caller); + encode_fh(xdr, &lock->fh); + encode_netobj(xdr, lock->oh.data, lock->oh.len); + + p = xdr_reserve_space(xdr, 4 + 8 + 8); + *p++ = cpu_to_be32(lock->svid); + + nlm4_compute_offsets(lock, &l_offset, &l_len); + p = xdr_encode_hyper(p, l_offset); + xdr_encode_hyper(p, l_len); +} + + +/* + * NLMv4 XDR encode functions + * + * NLMv4 argument types are defined in Appendix II of RFC 1813: + * "NFS Version 3 Protocol Specification" and Chapter 10 of X/Open's + * "Protocols for Interworking: XNFS, Version 3W". + */ + +/* + * struct nlm4_testargs { + * netobj cookie; + * bool exclusive; + * struct nlm4_lock alock; + * }; + */ +static int nlm4_xdr_enc_testargs(struct rpc_rqst *req, __be32 *p, + const struct nlm_args *args) +{ + const struct nlm_lock *lock = &args->lock; + struct xdr_stream xdr; + + xdr_init_encode(&xdr, &req->rq_snd_buf, p); + encode_cookie(&xdr, &args->cookie); + encode_bool(&xdr, lock->fl.fl_type == F_WRLCK); + encode_nlm4_lock(&xdr, lock); + return 0; +} + +/* + * struct nlm4_lockargs { + * netobj cookie; + * bool block; + * bool exclusive; + * struct nlm4_lock alock; + * bool reclaim; + * int state; + * }; + */ +static int nlm4_xdr_enc_lockargs(struct rpc_rqst *req, __be32 *p, + const struct nlm_args *args) +{ + const struct nlm_lock *lock = &args->lock; + struct xdr_stream xdr; + + xdr_init_encode(&xdr, &req->rq_snd_buf, p); + encode_cookie(&xdr, &args->cookie); + encode_bool(&xdr, args->block); + encode_bool(&xdr, lock->fl.fl_type == F_WRLCK); + encode_nlm4_lock(&xdr, lock); + encode_bool(&xdr, args->reclaim); + encode_int32(&xdr, args->state); + return 0; +} + +/* + * struct nlm4_cancargs { + * netobj cookie; + * bool block; + * bool exclusive; + * struct nlm4_lock alock; + * }; + */ +static int nlm4_xdr_enc_cancargs(struct rpc_rqst *req, __be32 *p, + const struct nlm_args *args) +{ + const struct nlm_lock *lock = &args->lock; + struct xdr_stream xdr; + + xdr_init_encode(&xdr, &req->rq_snd_buf, p); + encode_cookie(&xdr, &args->cookie); + encode_bool(&xdr, args->block); + encode_bool(&xdr, lock->fl.fl_type == F_WRLCK); + encode_nlm4_lock(&xdr, lock); + return 0; +} + +/* + * struct nlm4_unlockargs { + * netobj cookie; + * struct nlm4_lock alock; + * }; + */ +static int nlm4_xdr_enc_unlockargs(struct rpc_rqst *req, __be32 *p, + const struct nlm_args *args) +{ + const struct nlm_lock *lock = &args->lock; + struct xdr_stream xdr; + + xdr_init_encode(&xdr, &req->rq_snd_buf, p); + encode_cookie(&xdr, &args->cookie); + encode_nlm4_lock(&xdr, lock); + return 0; +} + +/* + * struct nlm4_res { + * netobj cookie; + * nlm4_stat stat; + * }; + */ +static int nlm4_xdr_enc_res(struct rpc_rqst *req, __be32 *p, + const struct nlm_res *result) +{ + struct xdr_stream xdr; + + xdr_init_encode(&xdr, &req->rq_snd_buf, p); + encode_cookie(&xdr, &result->cookie); + encode_nlm4_stat(&xdr, result->status); + return 0; +} + +/* + * union nlm4_testrply switch (nlm4_stats stat) { + * case NLM4_DENIED: + * struct nlm4_holder holder; + * default: + * void; + * }; + * + * struct nlm4_testres { + * netobj cookie; + * nlm4_testrply test_stat; + * }; + */ +static int nlm4_xdr_enc_testres(struct rpc_rqst *req, __be32 *p, + const struct nlm_res *result) +{ + struct xdr_stream xdr; + + xdr_init_encode(&xdr, &req->rq_snd_buf, p); + encode_cookie(&xdr, &result->cookie); + encode_nlm4_stat(&xdr, result->status); + if (result->status == nlm_lck_denied) + encode_nlm4_holder(&xdr, result); + return 0; +} + + +/* + * NLMv4 XDR decode functions + * + * NLMv4 argument types are defined in Appendix II of RFC 1813: + * "NFS Version 3 Protocol Specification" and Chapter 10 of X/Open's + * "Protocols for Interworking: XNFS, Version 3W". + */ + +/* + * union nlm4_testrply switch (nlm4_stats stat) { + * case NLM4_DENIED: + * struct nlm4_holder holder; + * default: + * void; + * }; + * + * struct nlm4_testres { + * netobj cookie; + * nlm4_testrply test_stat; + * }; + */ +static int decode_nlm4_testrply(struct xdr_stream *xdr, + struct nlm_res *result) +{ + int error; + + error = decode_nlm4_stat(xdr, &result->status); + if (unlikely(error)) + goto out; + if (result->status == nlm_lck_denied) + error = decode_nlm4_holder(xdr, result); +out: + return error; +} + +static int nlm4_xdr_dec_testres(struct rpc_rqst *req, __be32 *p, + struct nlm_res *result) +{ + struct xdr_stream xdr; + int error; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + error = decode_cookie(&xdr, &result->cookie); + if (unlikely(error)) + goto out; + error = decode_nlm4_testrply(&xdr, result); +out: + return error; +} + +/* + * struct nlm4_res { + * netobj cookie; + * nlm4_stat stat; + * }; + */ +static int nlm4_xdr_dec_res(struct rpc_rqst *req, __be32 *p, + struct nlm_res *result) +{ + struct xdr_stream xdr; + int error; + + xdr_init_decode(&xdr, &req->rq_rcv_buf, p); + error = decode_cookie(&xdr, &result->cookie); + if (unlikely(error)) + goto out; + error = decode_nlm4_stat(&xdr, &result->status); +out: + return error; +} + + +/* + * For NLM, a void procedure really returns nothing + */ +#define nlm4_xdr_dec_norep NULL + +#define PROC(proc, argtype, restype) \ +[NLMPROC_##proc] = { \ + .p_proc = NLMPROC_##proc, \ + .p_encode = (kxdrproc_t)nlm4_xdr_enc_##argtype, \ + .p_decode = (kxdrproc_t)nlm4_xdr_dec_##restype, \ + .p_arglen = NLM4_##argtype##_sz, \ + .p_replen = NLM4_##restype##_sz, \ + .p_statidx = NLMPROC_##proc, \ + .p_name = #proc, \ + } + +static struct rpc_procinfo nlm4_procedures[] = { + PROC(TEST, testargs, testres), + PROC(LOCK, lockargs, res), + PROC(CANCEL, cancargs, res), + PROC(UNLOCK, unlockargs, res), + PROC(GRANTED, testargs, res), + PROC(TEST_MSG, testargs, norep), + PROC(LOCK_MSG, lockargs, norep), + PROC(CANCEL_MSG, cancargs, norep), + PROC(UNLOCK_MSG, unlockargs, norep), + PROC(GRANTED_MSG, testargs, norep), + PROC(TEST_RES, testres, norep), + PROC(LOCK_RES, res, norep), + PROC(CANCEL_RES, res, norep), + PROC(UNLOCK_RES, res, norep), + PROC(GRANTED_RES, res, norep), +}; + +struct rpc_version nlm_version4 = { + .number = 4, + .nrprocs = ARRAY_SIZE(nlm4_procedures), + .procs = nlm4_procedures, +}; |