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Commit f98bac5a authored by Kinglong Mee's avatar Kinglong Mee Committed by J. Bruce Fields
Browse files

NFSD: Fix crash encoding lock reply on 32-bit 



Commit 8c7424cf "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: default avatarKinglong Mee <kinglongmee@gmail.com>
Fixes: 8c7424cf ""nfsd4: don't try to encode conflicting owner if low on space"
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent c3a45617

fs/nfsd/nfs4xdr.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -2879,6 +2879,7 @@ again: 
		 * return the conflicting open:

		 * return the conflicting open:

		 */

		 */

		if (conf->len) {

		if (conf->len) {

			kfree(conf->data);

			conf->len = 0;

			conf->len = 0;

			conf->data = NULL;

			conf->data = NULL;

			goto again;

			goto again;
@@ -2891,6 +2892,7 @@ again: 
	if (conf->len) {

	if (conf->len) {

		p = xdr_encode_opaque_fixed(p, &ld->ld_clientid, 8);

		p = xdr_encode_opaque_fixed(p, &ld->ld_clientid, 8);

		p = xdr_encode_opaque(p, conf->data, conf->len);

		p = xdr_encode_opaque(p, conf->data, conf->len);

		kfree(conf->data);

	}  else {  /* non - nfsv4 lock in conflict, no clientid nor owner */

	}  else {  /* non - nfsv4 lock in conflict, no clientid nor owner */

		p = xdr_encode_hyper(p, (u64)0); /* clientid */

		p = xdr_encode_hyper(p, (u64)0); /* clientid */

		*p++ = cpu_to_be32(0); /* length of owner name */

		*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);

		nfserr = nfsd4_encode_stateid(xdr, &lock->lk_resp_stateid);

	else if (nfserr == nfserr_denied)

	else if (nfserr == nfserr_denied)

		nfserr = nfsd4_encode_lock_denied(xdr, &lock->lk_denied);

		nfserr = nfsd4_encode_lock_denied(xdr, &lock->lk_denied);

	kfree(lock->lk_denied.ld_owner.data);



	return nfserr;

	return nfserr;

}

}