6.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chuck Lever chuck.lever@oracle.com
commit 3e7f011c255582d7c914133785bbba1990441713 upstream.
I've found that pynfs COMP6 now leaves the connection or lease in a strange state, which causes CLOSE9 to hang indefinitely. I've dug into it a little, but I haven't been able to root-cause it yet. However, I bisected to commit 48aab1606fa8 ("NFSD: Remove the cap on number of operations per NFSv4 COMPOUND").
Tianshuo Han also reports a potential vulnerability when decoding an NFSv4 COMPOUND. An attacker can place an arbitrarily large op count in the COMPOUND header, which results in:
[ 51.410584] nfsd: vmalloc error: size 1209533382144, exceeds total pages, mode:0xdc0(GFP_KERNEL|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0
when NFSD attempts to allocate the COMPOUND op array.
Let's restore the operation-per-COMPOUND limit, but increased to 200 for now.
Reported-by: tianshuo han hantianshuo233@gmail.com Reviewed-by: Jeff Layton jlayton@kernel.org Cc: stable@vger.kernel.org Tested-by: Tianshuo Han hantianshuo233@gmail.com Signed-off-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfsd/nfs4proc.c | 14 ++++++++++++-- fs/nfsd/nfs4state.c | 1 + fs/nfsd/nfs4xdr.c | 4 +++- fs/nfsd/nfsd.h | 3 +++ fs/nfsd/xdr4.h | 1 + 5 files changed, 20 insertions(+), 3 deletions(-)
--- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -2859,10 +2859,20 @@ nfsd4_proc_compound(struct svc_rqst *rqs
rqstp->rq_lease_breaker = (void **)&cstate->clp;
- trace_nfsd_compound(rqstp, args->tag, args->taglen, args->opcnt); + trace_nfsd_compound(rqstp, args->tag, args->taglen, args->client_opcnt); while (!status && resp->opcnt < args->opcnt) { op = &args->ops[resp->opcnt++];
+ if (unlikely(resp->opcnt == NFSD_MAX_OPS_PER_COMPOUND)) { + /* If there are still more operations to process, + * stop here and report NFS4ERR_RESOURCE. */ + if (cstate->minorversion == 0 && + args->client_opcnt > resp->opcnt) { + op->status = nfserr_resource; + goto encode_op; + } + } + /* * The XDR decode routines may have pre-set op->status; * for example, if there is a miscellaneous XDR error @@ -2939,7 +2949,7 @@ encode_op: status = op->status; }
- trace_nfsd_compound_status(args->opcnt, resp->opcnt, + trace_nfsd_compound_status(args->client_opcnt, resp->opcnt, status, nfsd4_op_name(op->opnum));
nfsd4_cstate_clear_replay(cstate); --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -3865,6 +3865,7 @@ static __be32 check_forechannel_attrs(st ca->headerpadsz = 0; ca->maxreq_sz = min_t(u32, ca->maxreq_sz, maxrpc); ca->maxresp_sz = min_t(u32, ca->maxresp_sz, maxrpc); + ca->maxops = min_t(u32, ca->maxops, NFSD_MAX_OPS_PER_COMPOUND); ca->maxresp_cached = min_t(u32, ca->maxresp_cached, NFSD_SLOT_CACHE_SIZE + NFSD_MIN_HDR_SEQ_SZ); ca->maxreqs = min_t(u32, ca->maxreqs, NFSD_MAX_SLOTS_PER_SESSION); --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -2488,8 +2488,10 @@ nfsd4_decode_compound(struct nfsd4_compo
if (xdr_stream_decode_u32(argp->xdr, &argp->minorversion) < 0) return false; - if (xdr_stream_decode_u32(argp->xdr, &argp->opcnt) < 0) + if (xdr_stream_decode_u32(argp->xdr, &argp->client_opcnt) < 0) return false; + argp->opcnt = min_t(u32, argp->client_opcnt, + NFSD_MAX_OPS_PER_COMPOUND);
if (argp->opcnt > ARRAY_SIZE(argp->iops)) { argp->ops = vcalloc(argp->opcnt, sizeof(*argp->ops)); --- a/fs/nfsd/nfsd.h +++ b/fs/nfsd/nfsd.h @@ -57,6 +57,9 @@ struct readdir_cd { __be32 err; /* 0, nfserr, or nfserr_eof */ };
+/* Maximum number of operations per session compound */ +#define NFSD_MAX_OPS_PER_COMPOUND 200 + struct nfsd_genl_rqstp { struct sockaddr rq_daddr; struct sockaddr rq_saddr; --- a/fs/nfsd/xdr4.h +++ b/fs/nfsd/xdr4.h @@ -903,6 +903,7 @@ struct nfsd4_compoundargs { char * tag; u32 taglen; u32 minorversion; + u32 client_opcnt; u32 opcnt; bool splice_ok; struct nfsd4_op *ops;