quota: do not allow setting of quota limits to too high values

We should check whether quota limits set via Q_SETQUOTA are not exceeding
limits which quota format is able to handle.

Signed-off-by: Andrew Perepechko <andrew.perepechko@sun.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 25 insertions, 5 deletions

diff --git a/fs/dquot.c b/fs/dquot.c
index 41b9dbd68b0e..24eef582d2a0 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -1709,10 +1709,19 @@ int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *d
 }
 
 /* Generic routine for setting common part of quota structure */
-static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
+static int do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
 {
         struct mem_dqblk *dm = &dquot->dq_dqb;
         int check_blim = 0, check_ilim = 0;
+        struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_type];
+
+        if ((di->dqb_valid & QIF_BLIMITS &&
+             (di->dqb_bhardlimit > dqi->dqi_maxblimit ||
+              di->dqb_bsoftlimit > dqi->dqi_maxblimit)) ||
+            (di->dqb_valid & QIF_ILIMITS &&
+             (di->dqb_ihardlimit > dqi->dqi_maxilimit ||
+              di->dqb_isoftlimit > dqi->dqi_maxilimit)))
+                return -ERANGE;
 
         spin_lock(&dq_data_lock);
         if (di->dqb_valid & QIF_SPACE) {
@@ -1744,7 +1753,7 @@ static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
                         clear_bit(DQ_BLKS_B, &dquot->dq_flags);
                 }
                 else if (!(di->dqb_valid & QIF_BTIME))  /* Set grace only if user hasn't provided his own... */
-                        dm->dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
+                        dm->dqb_btime = get_seconds() + dqi->dqi_bgrace;
         }
         if (check_ilim) {
                 if (!dm->dqb_isoftlimit || dm->dqb_curinodes < dm->dqb_isoftlimit) {
@@ -1752,7 +1761,7 @@ static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
                         clear_bit(DQ_INODES_B, &dquot->dq_flags);
                 }
                 else if (!(di->dqb_valid & QIF_ITIME))  /* Set grace only if user hasn't provided his own... */
-                        dm->dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
+                        dm->dqb_itime = get_seconds() + dqi->dqi_igrace;
         }
         if (dm->dqb_bhardlimit || dm->dqb_bsoftlimit || dm->dqb_ihardlimit || dm->dqb_isoftlimit)
                 clear_bit(DQ_FAKE_B, &dquot->dq_flags);
@@ -1760,21 +1769,24 @@ static void do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
                 set_bit(DQ_FAKE_B, &dquot->dq_flags);
         spin_unlock(&dq_data_lock);
         mark_dquot_dirty(dquot);
+
+        return 0;
 }
 
 int vfs_set_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di)
 {
         struct dquot *dquot;
+        int rc;
 
         mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
         if (!(dquot = dqget(sb, id, type))) {
                 mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
                 return -ESRCH;
         }
-        do_set_dqblk(dquot, di);
+        rc = do_set_dqblk(dquot, di);
         dqput(dquot);
         mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
-        return 0;
+        return rc;
 }
 
 /* Generic routine for getting common part of quota file information */
diff --git a/fs/quota_v1.c b/fs/quota_v1.c
index f3841f233069..a6cf9269105c 100644
--- a/fs/quota_v1.c
+++ b/fs/quota_v1.c
@@ -139,6 +139,9 @@ static int v1_read_file_info(struct super_block *sb, int type)
                 goto out;
         }
         ret = 0;
+        /* limits are stored as unsigned 32-bit data */
+        dqopt->info[type].dqi_maxblimit = 0xffffffff;
+        dqopt->info[type].dqi_maxilimit = 0xffffffff;
         dqopt->info[type].dqi_igrace = dqblk.dqb_itime ? dqblk.dqb_itime : MAX_IQ_TIME;
         dqopt->info[type].dqi_bgrace = dqblk.dqb_btime ? dqblk.dqb_btime : MAX_DQ_TIME;
 out:
diff --git a/fs/quota_v2.c b/fs/quota_v2.c
index c519a583e681..23b647f25d08 100644
--- a/fs/quota_v2.c
+++ b/fs/quota_v2.c
@@ -59,6 +59,9 @@ static int v2_read_file_info(struct super_block *sb, int type)
                         sb->s_id);
                 return -1;
         }
+        /* limits are stored as unsigned 32-bit data */
+        info->dqi_maxblimit = 0xffffffff;
+        info->dqi_maxilimit = 0xffffffff;
         info->dqi_bgrace = le32_to_cpu(dinfo.dqi_bgrace);
         info->dqi_igrace = le32_to_cpu(dinfo.dqi_igrace);
         info->dqi_flags = le32_to_cpu(dinfo.dqi_flags);
diff --git a/include/linux/quota.h b/include/linux/quota.h
index eb560d031acd..326cb80e3867 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -206,6 +206,8 @@ struct mem_dqinfo {
         unsigned long dqi_flags;
         unsigned int dqi_bgrace;
         unsigned int dqi_igrace;
+        qsize_t dqi_maxblimit;
+        qsize_t dqi_maxilimit;
         union {
                 struct v1_mem_dqinfo v1_i;
                 struct v2_mem_dqinfo v2_i;