From f98bac5a30b60a2fca854dd5ee7256221d8ccf0a Mon Sep 17 00:00:00 2001 From: Kinglong Mee Date: Mon, 7 Jul 2014 22:10:56 +0800 Subject: [PATCH] NFSD: Fix crash encoding lock reply on 32-bit Commit 8c7424cff6 "nfsd4: don't try to encode conflicting owner if low on space" forgot to free conf->data in nfsd4_encode_lockt and before sign conf->data to NULL in nfsd4_encode_lock_denied, causing a leak. Worse, kfree() can be called on an uninitialized pointer in the case of a succesful lock (or one that fails for a reason other than a conflict). (Note that lock->lk_denied.ld_owner.data appears it should be zero here, until you notice that it's one arm of a union the other arm of which is written to in the succesful case by the memcpy(&lock->lk_resp_stateid, &lock_stp->st_stid.sc_stateid, sizeof(stateid_t)); in nfsd4_lock(). In the 32-bit case this overwrites ld_owner.data.) Signed-off-by: Kinglong Mee Fixes: 8c7424cff6 ""nfsd4: don't try to encode conflicting owner if low on space" Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4xdr.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index b56b1cc02718..944275c8f56d 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -2879,6 +2879,7 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld) * return the conflicting open: */ if (conf->len) { + kfree(conf->data); conf->len = 0; conf->data = NULL; goto again; @@ -2891,6 +2892,7 @@ nfsd4_encode_lock_denied(struct xdr_stream *xdr, struct nfsd4_lock_denied *ld) if (conf->len) { p = xdr_encode_opaque_fixed(p, &ld->ld_clientid, 8); p = xdr_encode_opaque(p, conf->data, conf->len); + kfree(conf->data); } else { /* non - nfsv4 lock in conflict, no clientid nor owner */ p = xdr_encode_hyper(p, (u64)0); /* clientid */ *p++ = cpu_to_be32(0); /* length of owner name */ @@ -2907,7 +2909,7 @@ nfsd4_encode_lock(struct nfsd4_compoundres *resp, __be32 nfserr, struct nfsd4_lo nfserr = nfsd4_encode_stateid(xdr, &lock->lk_resp_stateid); else if (nfserr == nfserr_denied) nfserr = nfsd4_encode_lock_denied(xdr, &lock->lk_denied); - kfree(lock->lk_denied.ld_owner.data); + return nfserr; }