Dan Carpenter
2015-Apr-09 19:39 UTC
[Ocfs2-devel] vfs: Add general support to enforce project quota limits
Hello Li Xi, The patch 847aac644e92: "vfs: Add general support to enforce project quota limits" from Mar 19, 2015, leads to the following static checker warning: fs/ocfs2/quota_local.c:183 ocfs2_local_check_quota_file() error: buffer overflow 'lmagics' 2 <= 2 fs/ocfs2/quota_local.c 159 /* Check whether we understand format of quota files */ 160 static int ocfs2_local_check_quota_file(struct super_block *sb, int type) 161 { 162 unsigned int lmagics[OCFS2_MAXQUOTAS] = OCFS2_LOCAL_QMAGICS; ^^^^^^^^^^^^^^^ This is 2. Maybe the fix is to change this to MAXQUOTAS. 163 unsigned int lversions[OCFS2_MAXQUOTAS] = OCFS2_LOCAL_QVERSIONS; 164 unsigned int gmagics[OCFS2_MAXQUOTAS] = OCFS2_GLOBAL_QMAGICS; 165 unsigned int gversions[OCFS2_MAXQUOTAS] = OCFS2_GLOBAL_QVERSIONS; 166 unsigned int ino[OCFS2_MAXQUOTAS] = { USER_QUOTA_SYSTEM_INODE, 167 GROUP_QUOTA_SYSTEM_INODE }; 168 struct buffer_head *bh = NULL; 169 struct inode *linode = sb_dqopt(sb)->files[type]; 170 struct inode *ginode = NULL; 171 struct ocfs2_disk_dqheader *dqhead; 172 int status, ret = 0; 173 174 /* First check whether we understand local quota file */ 175 status = ocfs2_read_quota_block(linode, 0, &bh); 176 if (status) { 177 mlog_errno(status); 178 mlog(ML_ERROR, "failed to read quota file header (type=%d)\n", 179 type); 180 goto out_err; 181 } 182 dqhead = (struct ocfs2_disk_dqheader *)(bh->b_data); 183 if (le32_to_cpu(dqhead->dqh_magic) != lmagics[type]) { ^^^^^^^^^^^^^ This is one past the end of the array. It used to be limitied in do_quotactl(). if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS)) The old logic was the XFS had 3 quotas and everyone else had 2 but now we raised MAXQUOTAS to 3 as well. 184 mlog(ML_ERROR, "quota file magic does not match (%u != %u)," 185 " type=%d\n", le32_to_cpu(dqhead->dqh_magic), 186 lmagics[type], type); 187 goto out_err; 188 } regards, dan carpenter
Dan Carpenter
2015-Apr-09 19:46 UTC
[Ocfs2-devel] vfs: Add general support to enforce project quota limits
Here is a related warning. I haven't investigated it. fs/quota/quota_v1.c:149 v1_check_quota_file() error: buffer overflow 'quota_magics' 2 <= 2 regards, dan carpenter
Jan Kara
2015-Apr-13 10:10 UTC
[Ocfs2-devel] vfs: Add general support to enforce project quota limits
Hello Dan, On Thu 09-04-15 22:39:54, Dan Carpenter wrote:> The patch 847aac644e92: "vfs: Add general support to enforce project > quota limits" from Mar 19, 2015, leads to the following static > checker warning:Thanks for letting us know.> fs/ocfs2/quota_local.c:183 ocfs2_local_check_quota_file() > error: buffer overflow 'lmagics' 2 <= 2OK, so the checker thinks that 'type' argument can be larger than OCFS2_MAXQUOTAS.> fs/ocfs2/quota_local.c > 159 /* Check whether we understand format of quota files */ > 160 static int ocfs2_local_check_quota_file(struct super_block *sb, int type) > 161 { > 162 unsigned int lmagics[OCFS2_MAXQUOTAS] = OCFS2_LOCAL_QMAGICS; > ^^^^^^^^^^^^^^^ > This is 2. Maybe the fix is to change this to MAXQUOTAS.No, that isn't the right fix. OCFS2 still supports only two quota types. The right fix is to make sure that type == 2 cannot reach filesystems which don't support it. See below...> 163 unsigned int lversions[OCFS2_MAXQUOTAS] = OCFS2_LOCAL_QVERSIONS; > 164 unsigned int gmagics[OCFS2_MAXQUOTAS] = OCFS2_GLOBAL_QMAGICS; > 165 unsigned int gversions[OCFS2_MAXQUOTAS] = OCFS2_GLOBAL_QVERSIONS; > 166 unsigned int ino[OCFS2_MAXQUOTAS] = { USER_QUOTA_SYSTEM_INODE, > 167 GROUP_QUOTA_SYSTEM_INODE }; > 168 struct buffer_head *bh = NULL; > 169 struct inode *linode = sb_dqopt(sb)->files[type]; > 170 struct inode *ginode = NULL; > 171 struct ocfs2_disk_dqheader *dqhead; > 172 int status, ret = 0; > 173 > 174 /* First check whether we understand local quota file */ > 175 status = ocfs2_read_quota_block(linode, 0, &bh); > 176 if (status) { > 177 mlog_errno(status); > 178 mlog(ML_ERROR, "failed to read quota file header (type=%d)\n", > 179 type); > 180 goto out_err; > 181 } > 182 dqhead = (struct ocfs2_disk_dqheader *)(bh->b_data); > 183 if (le32_to_cpu(dqhead->dqh_magic) != lmagics[type]) { > ^^^^^^^^^^^^^ > This is one past the end of the array. It used to be limitied in > do_quotactl(). > > if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS)) > > The old logic was the XFS had 3 quotas and everyone else had 2 but now > we raised MAXQUOTAS to 3 as well.Yes, but we have there a test: if (!(sb->s_quota_types & (1 << type))) return -EINVAL; which also limits allowed types. And OCFS2 sets this to QTYPE_MASK_USR | QTYPE_MASK_GRP so type == 2 cannot reach it via quotactl(). So either this is a false positive or there's some other path how type == 2 can reach OCFS2 which I'm missing and I'd definitely like to learn about it. Can you investigate a bit please? Thanks. Honza -- Jan Kara <jack at suse.cz> SUSE Labs, CR