From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 21DA117BB25; Sun, 24 Mar 2024 23:42:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711323766; cv=none; b=UJp6GzY6WJrqdkNnBHwD8fMq7Jnvmlh0gFVF990JeDCRdCHVfsJ4RyBQI1te8SD5Xf6XXA5bk0O6/QKqfyyqLr0Wn4tSkBQcPBI4REciS87myTcLsQpMpCpOuHSfy+mENi0Xcl0KjYr5ZlqdpfcEQxD1rkco1PRo2KGFgr0xV+o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711323766; c=relaxed/simple; bh=pWTdEafqnwz0t2R//u3qHlLZPkTkESyZ/4bwNpLUyX4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GpfOS8ut4RT1G68xQR6d7w3oXCJS2FMe3YU4+BShzryI3+RgKKjGP5nk2OS04RAQk8QpwYl0B+I23c0PLdubhTYSn1AC8vXjd3tLubdk8lhvzSzeBymyxjIAd5XIY7+RqmHgUly0FrvJqrH53x7CZuAY674LjVXdkAetdb1MlLI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HpJE57HJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HpJE57HJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63EF8C43394; Sun, 24 Mar 2024 23:42:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711323765; bh=pWTdEafqnwz0t2R//u3qHlLZPkTkESyZ/4bwNpLUyX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HpJE57HJRk7d2Bz78b86SmdGVXGearzsRZekfYKI6xEd7x+E0gjRwlz+z3NUTbC2c ehf1smbObfp8NWD+Cdpa8oZt13WYff9XMOiH9sC2hyCpGuVnjhA29sgS/t6mDpYaxH Lw6liLEANCTA0kdbdkG9GVjm6FessSAczPiddgLLwFdcBSD7F55MEQSZaSwEFWdLBn szVOT0J9vKeJzRn0ZW8REauwDEHPros/bQw3EX0jlFIPH/SfrnozK1U5w8sej8KQLj ril+Ankx17VnC8hooFUgu4gnRkXsu7DrUVwUatLZJwXVBbaP4Tw7dtfnHZkaQNINfr jzZw/kcldNQrg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Wang Jianjian , Jan Kara , Sasha Levin Subject: [PATCH 5.10 140/238] quota: Fix potential NULL pointer dereference Date: Sun, 24 Mar 2024 19:38:48 -0400 Message-ID: <20240324234027.1354210-141-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324234027.1354210-1-sashal@kernel.org> References: <20240324234027.1354210-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Wang Jianjian [ Upstream commit d0aa72604fbd80c8aabb46eda00535ed35570f1f ] Below race may cause NULL pointer dereference P1 P2 dquot_free_inode quota_off drop_dquot_ref remove_dquot_ref dquots = i_dquot(inode) dquots = i_dquot(inode) srcu_read_lock dquots[cnt]) != NULL (1) dquots[type] = NULL (2) spin_lock(&dquots[cnt]->dq_dqb_lock) (3) .... If dquot_free_inode(or other routines) checks inode's quota pointers (1) before quota_off sets it to NULL(2) and use it (3) after that, NULL pointer dereference will be triggered. So let's fix it by using a temporary pointer to avoid this issue. Signed-off-by: Wang Jianjian Signed-off-by: Jan Kara Message-Id: <20240202081852.2514092-1-wangjianjian3@huawei.com> Stable-dep-of: 179b8c97ebf6 ("quota: Fix rcu annotations of inode dquot pointers") Signed-off-by: Sasha Levin --- fs/quota/dquot.c | 98 ++++++++++++++++++++++++++++-------------------- 1 file changed, 57 insertions(+), 41 deletions(-) diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index 77578332e35ae..3f19ef2cc186d 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -401,15 +401,17 @@ int dquot_mark_dquot_dirty(struct dquot *dquot) EXPORT_SYMBOL(dquot_mark_dquot_dirty); /* Dirtify all the dquots - this can block when journalling */ -static inline int mark_all_dquot_dirty(struct dquot * const *dquot) +static inline int mark_all_dquot_dirty(struct dquot * const *dquots) { int ret, err, cnt; + struct dquot *dquot; ret = err = 0; for (cnt = 0; cnt < MAXQUOTAS; cnt++) { - if (dquot[cnt]) + dquot = srcu_dereference(dquots[cnt], &dquot_srcu); + if (dquot) /* Even in case of error we have to continue */ - ret = mark_dquot_dirty(dquot[cnt]); + ret = mark_dquot_dirty(dquot); if (!err) err = ret; } @@ -1686,6 +1688,7 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags) struct dquot_warn warn[MAXQUOTAS]; int reserve = flags & DQUOT_SPACE_RESERVE; struct dquot **dquots; + struct dquot *dquot; if (!inode_quota_active(inode)) { if (reserve) { @@ -1705,27 +1708,26 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags) index = srcu_read_lock(&dquot_srcu); spin_lock(&inode->i_lock); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { - if (!dquots[cnt]) + dquot = srcu_dereference(dquots[cnt], &dquot_srcu); + if (!dquot) continue; if (reserve) { - ret = dquot_add_space(dquots[cnt], 0, number, flags, - &warn[cnt]); + ret = dquot_add_space(dquot, 0, number, flags, &warn[cnt]); } else { - ret = dquot_add_space(dquots[cnt], number, 0, flags, - &warn[cnt]); + ret = dquot_add_space(dquot, number, 0, flags, &warn[cnt]); } if (ret) { /* Back out changes we already did */ for (cnt--; cnt >= 0; cnt--) { - if (!dquots[cnt]) + dquot = srcu_dereference(dquots[cnt], &dquot_srcu); + if (!dquot) continue; - spin_lock(&dquots[cnt]->dq_dqb_lock); + spin_lock(&dquot->dq_dqb_lock); if (reserve) - dquot_free_reserved_space(dquots[cnt], - number); + dquot_free_reserved_space(dquot, number); else - dquot_decr_space(dquots[cnt], number); - spin_unlock(&dquots[cnt]->dq_dqb_lock); + dquot_decr_space(dquot, number); + spin_unlock(&dquot->dq_dqb_lock); } spin_unlock(&inode->i_lock); goto out_flush_warn; @@ -1756,6 +1758,7 @@ int dquot_alloc_inode(struct inode *inode) int cnt, ret = 0, index; struct dquot_warn warn[MAXQUOTAS]; struct dquot * const *dquots; + struct dquot *dquot; if (!inode_quota_active(inode)) return 0; @@ -1766,17 +1769,19 @@ int dquot_alloc_inode(struct inode *inode) index = srcu_read_lock(&dquot_srcu); spin_lock(&inode->i_lock); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { - if (!dquots[cnt]) + dquot = srcu_dereference(dquots[cnt], &dquot_srcu); + if (!dquot) continue; - ret = dquot_add_inodes(dquots[cnt], 1, &warn[cnt]); + ret = dquot_add_inodes(dquot, 1, &warn[cnt]); if (ret) { for (cnt--; cnt >= 0; cnt--) { - if (!dquots[cnt]) + dquot = srcu_dereference(dquots[cnt], &dquot_srcu); + if (!dquot) continue; /* Back out changes we already did */ - spin_lock(&dquots[cnt]->dq_dqb_lock); - dquot_decr_inodes(dquots[cnt], 1); - spin_unlock(&dquots[cnt]->dq_dqb_lock); + spin_lock(&dquot->dq_dqb_lock); + dquot_decr_inodes(dquot, 1); + spin_unlock(&dquot->dq_dqb_lock); } goto warn_put_all; } @@ -1798,6 +1803,7 @@ EXPORT_SYMBOL(dquot_alloc_inode); int dquot_claim_space_nodirty(struct inode *inode, qsize_t number) { struct dquot **dquots; + struct dquot *dquot; int cnt, index; if (!inode_quota_active(inode)) { @@ -1813,9 +1819,8 @@ int dquot_claim_space_nodirty(struct inode *inode, qsize_t number) spin_lock(&inode->i_lock); /* Claim reserved quotas to allocated quotas */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) { - if (dquots[cnt]) { - struct dquot *dquot = dquots[cnt]; - + dquot = srcu_dereference(dquots[cnt], &dquot_srcu); + if (dquot) { spin_lock(&dquot->dq_dqb_lock); if (WARN_ON_ONCE(dquot->dq_dqb.dqb_rsvspace < number)) number = dquot->dq_dqb.dqb_rsvspace; @@ -1840,6 +1845,7 @@ EXPORT_SYMBOL(dquot_claim_space_nodirty); void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number) { struct dquot **dquots; + struct dquot *dquot; int cnt, index; if (!inode_quota_active(inode)) { @@ -1855,9 +1861,8 @@ void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number) spin_lock(&inode->i_lock); /* Claim reserved quotas to allocated quotas */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) { - if (dquots[cnt]) { - struct dquot *dquot = dquots[cnt]; - + dquot = srcu_dereference(dquots[cnt], &dquot_srcu); + if (dquot) { spin_lock(&dquot->dq_dqb_lock); if (WARN_ON_ONCE(dquot->dq_dqb.dqb_curspace < number)) number = dquot->dq_dqb.dqb_curspace; @@ -1884,6 +1889,7 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags) unsigned int cnt; struct dquot_warn warn[MAXQUOTAS]; struct dquot **dquots; + struct dquot *dquot; int reserve = flags & DQUOT_SPACE_RESERVE, index; if (!inode_quota_active(inode)) { @@ -1904,17 +1910,18 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags) int wtype; warn[cnt].w_type = QUOTA_NL_NOWARN; - if (!dquots[cnt]) + dquot = srcu_dereference(dquots[cnt], &dquot_srcu); + if (!dquot) continue; - spin_lock(&dquots[cnt]->dq_dqb_lock); - wtype = info_bdq_free(dquots[cnt], number); + spin_lock(&dquot->dq_dqb_lock); + wtype = info_bdq_free(dquot, number); if (wtype != QUOTA_NL_NOWARN) - prepare_warning(&warn[cnt], dquots[cnt], wtype); + prepare_warning(&warn[cnt], dquot, wtype); if (reserve) - dquot_free_reserved_space(dquots[cnt], number); + dquot_free_reserved_space(dquot, number); else - dquot_decr_space(dquots[cnt], number); - spin_unlock(&dquots[cnt]->dq_dqb_lock); + dquot_decr_space(dquot, number); + spin_unlock(&dquot->dq_dqb_lock); } if (reserve) *inode_reserved_space(inode) -= number; @@ -1939,6 +1946,7 @@ void dquot_free_inode(struct inode *inode) unsigned int cnt; struct dquot_warn warn[MAXQUOTAS]; struct dquot * const *dquots; + struct dquot *dquot; int index; if (!inode_quota_active(inode)) @@ -1949,16 +1957,16 @@ void dquot_free_inode(struct inode *inode) spin_lock(&inode->i_lock); for (cnt = 0; cnt < MAXQUOTAS; cnt++) { int wtype; - warn[cnt].w_type = QUOTA_NL_NOWARN; - if (!dquots[cnt]) + dquot = srcu_dereference(dquots[cnt], &dquot_srcu); + if (!dquot) continue; - spin_lock(&dquots[cnt]->dq_dqb_lock); - wtype = info_idq_free(dquots[cnt], 1); + spin_lock(&dquot->dq_dqb_lock); + wtype = info_idq_free(dquot, 1); if (wtype != QUOTA_NL_NOWARN) - prepare_warning(&warn[cnt], dquots[cnt], wtype); - dquot_decr_inodes(dquots[cnt], 1); - spin_unlock(&dquots[cnt]->dq_dqb_lock); + prepare_warning(&warn[cnt], dquot, wtype); + dquot_decr_inodes(dquot, 1); + spin_unlock(&dquot->dq_dqb_lock); } spin_unlock(&inode->i_lock); mark_all_dquot_dirty(dquots); @@ -1985,7 +1993,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to) qsize_t rsv_space = 0; qsize_t inode_usage = 1; struct dquot *transfer_from[MAXQUOTAS] = {}; - int cnt, ret = 0; + int cnt, index, ret = 0; char is_valid[MAXQUOTAS] = {}; struct dquot_warn warn_to[MAXQUOTAS]; struct dquot_warn warn_from_inodes[MAXQUOTAS]; @@ -2074,8 +2082,16 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to) spin_unlock(&inode->i_lock); spin_unlock(&dq_data_lock); + /* + * These arrays are local and we hold dquot references so we don't need + * the srcu protection but still take dquot_srcu to avoid warning in + * mark_all_dquot_dirty(). + */ + index = srcu_read_lock(&dquot_srcu); mark_all_dquot_dirty(transfer_from); mark_all_dquot_dirty(transfer_to); + srcu_read_unlock(&dquot_srcu, index); + flush_warnings(warn_to); flush_warnings(warn_from_inodes); flush_warnings(warn_from_space); -- 2.43.0