udf: Fortify LVID loading

A user has reported an oops in udf_statfs() that was caused by
numOfPartitions entry in LVID structure being corrupted. Fix the problem
by verifying whether numOfPartitions makes sense at least to the extent
that LVID fits into a single block as it should.

Reported-by: Juergen Weigert <jw@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/udf/ialloc.c b/fs/udf/ialloc.c
index 7e5aae4..6eaf5ed 100644 (file)
--- a/fs/udf/ialloc.c
+++ b/fs/udf/ialloc.c
@@ -30,18 +30,17 @@ void udf_free_inode(struct inode *inode)
 {
        struct super_block *sb = inode->i_sb;
        struct udf_sb_info *sbi = UDF_SB(sb);
+       struct logicalVolIntegrityDescImpUse *lvidiu = udf_sb_lvidiu(sb);
 
-       mutex_lock(&sbi->s_alloc_mutex);
-       if (sbi->s_lvid_bh) {
-               struct logicalVolIntegrityDescImpUse *lvidiu =
-                                                       udf_sb_lvidiu(sbi);
+       if (lvidiu) {
+               mutex_lock(&sbi->s_alloc_mutex);
                if (S_ISDIR(inode->i_mode))
                        le32_add_cpu(&lvidiu->numDirs, -1);
                else
                        le32_add_cpu(&lvidiu->numFiles, -1);
                udf_updated_lvid(sb);
+               mutex_unlock(&sbi->s_alloc_mutex);
        }
-       mutex_unlock(&sbi->s_alloc_mutex);
 
        udf_free_blocks(sb, NULL, &UDF_I(inode)->i_location, 0, 1);
 }
@@ -55,6 +54,7 @@ struct inode *udf_new_inode(struct inode *dir, umode_t mode, int *err)
        uint32_t start = UDF_I(dir)->i_location.logicalBlockNum;
        struct udf_inode_info *iinfo;
        struct udf_inode_info *dinfo = UDF_I(dir);
+       struct logicalVolIntegrityDescImpUse *lvidiu;
 
        inode = new_inode(sb);
 
@@ -92,12 +92,10 @@ struct inode *udf_new_inode(struct inode *dir, umode_t mode, int *err)
                return NULL;
        }
 
-       if (sbi->s_lvid_bh) {
-               struct logicalVolIntegrityDescImpUse *lvidiu;
-
+       lvidiu = udf_sb_lvidiu(sb);
+       if (lvidiu) {
                iinfo->i_unique = lvid_get_unique_id(sb);
                mutex_lock(&sbi->s_alloc_mutex);
-               lvidiu = udf_sb_lvidiu(sbi);
                if (S_ISDIR(mode))
                        le32_add_cpu(&lvidiu->numDirs, 1);
                else

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 839a2ba..9121938 100644 (file)
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -94,13 +94,25 @@ static unsigned int udf_count_free(struct super_block *);
 static int udf_statfs(struct dentry *, struct kstatfs *);
 static int udf_show_options(struct seq_file *, struct dentry *);
 
-struct logicalVolIntegrityDescImpUse *udf_sb_lvidiu(struct udf_sb_info *sbi)
+struct logicalVolIntegrityDescImpUse *udf_sb_lvidiu(struct super_block *sb)
 {
-       struct logicalVolIntegrityDesc *lvid =
-               (struct logicalVolIntegrityDesc *)sbi->s_lvid_bh->b_data;
-       __u32 number_of_partitions = le32_to_cpu(lvid->numOfPartitions);
-       __u32 offset = number_of_partitions * 2 *
-                               sizeof(uint32_t)/sizeof(uint8_t);
+       struct logicalVolIntegrityDesc *lvid;
+       unsigned int partnum;
+       unsigned int offset;
+
+       if (!UDF_SB(sb)->s_lvid_bh)
+               return NULL;
+       lvid = (struct logicalVolIntegrityDesc *)UDF_SB(sb)->s_lvid_bh->b_data;
+       partnum = le32_to_cpu(lvid->numOfPartitions);
+       if ((sb->s_blocksize - sizeof(struct logicalVolIntegrityDescImpUse) -
+            offsetof(struct logicalVolIntegrityDesc, impUse)) /
+            (2 * sizeof(uint32_t)) < partnum) {
+               udf_err(sb, "Logical volume integrity descriptor corrupted "
+                       "(numOfPartitions = %u)!\n", partnum);
+               return NULL;
+       }
+       /* The offset is to skip freeSpaceTable and sizeTable arrays */
+       offset = partnum * 2 * sizeof(uint32_t);
        return (struct logicalVolIntegrityDescImpUse *)&(lvid->impUse[offset]);
 }
 
@@ -629,9 +641,10 @@ static int udf_remount_fs(struct super_block *sb, int *flags, char *options)
        struct udf_options uopt;
        struct udf_sb_info *sbi = UDF_SB(sb);
        int error = 0;
+       struct logicalVolIntegrityDescImpUse *lvidiu = udf_sb_lvidiu(sb);
 
-       if (sbi->s_lvid_bh) {
-               int write_rev = le16_to_cpu(udf_sb_lvidiu(sbi)->minUDFWriteRev);
+       if (lvidiu) {
+               int write_rev = le16_to_cpu(lvidiu->minUDFWriteRev);
                if (write_rev > UDF_MAX_WRITE_VERSION && !(*flags & MS_RDONLY))
                        return -EACCES;
        }
@@ -1905,11 +1918,12 @@ static void udf_open_lvid(struct super_block *sb)
 
        if (!bh)
                return;
-
-       mutex_lock(&sbi->s_alloc_mutex);
        lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
-       lvidiu = udf_sb_lvidiu(sbi);
+       lvidiu = udf_sb_lvidiu(sb);
+       if (!lvidiu)
+               return;
 
+       mutex_lock(&sbi->s_alloc_mutex);
        lvidiu->impIdent.identSuffix[0] = UDF_OS_CLASS_UNIX;
        lvidiu->impIdent.identSuffix[1] = UDF_OS_ID_LINUX;
        udf_time_to_disk_stamp(&lvid->recordingDateAndTime,
@@ -1937,10 +1951,12 @@ static void udf_close_lvid(struct super_block *sb)
 
        if (!bh)
                return;
+       lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
+       lvidiu = udf_sb_lvidiu(sb);
+       if (!lvidiu)
+               return;
 
        mutex_lock(&sbi->s_alloc_mutex);
-       lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
-       lvidiu = udf_sb_lvidiu(sbi);
        lvidiu->impIdent.identSuffix[0] = UDF_OS_CLASS_UNIX;
        lvidiu->impIdent.identSuffix[1] = UDF_OS_ID_LINUX;
        udf_time_to_disk_stamp(&lvid->recordingDateAndTime, CURRENT_TIME);
@@ -2093,15 +2109,19 @@ static int udf_fill_super(struct super_block *sb, void *options, int silent)
 
        if (sbi->s_lvid_bh) {
                struct logicalVolIntegrityDescImpUse *lvidiu =
-                                                       udf_sb_lvidiu(sbi);
-               uint16_t minUDFReadRev = le16_to_cpu(lvidiu->minUDFReadRev);
-               uint16_t minUDFWriteRev = le16_to_cpu(lvidiu->minUDFWriteRev);
-               /* uint16_t maxUDFWriteRev =
-                               le16_to_cpu(lvidiu->maxUDFWriteRev); */
+                                                       udf_sb_lvidiu(sb);
+               uint16_t minUDFReadRev;
+               uint16_t minUDFWriteRev;
 
+               if (!lvidiu) {
+                       ret = -EINVAL;
+                       goto error_out;
+               }
+               minUDFReadRev = le16_to_cpu(lvidiu->minUDFReadRev);
+               minUDFWriteRev = le16_to_cpu(lvidiu->minUDFWriteRev);
                if (minUDFReadRev > UDF_MAX_READ_VERSION) {
                        udf_err(sb, "minUDFReadRev=%x (max is %x)\n",
-                               le16_to_cpu(lvidiu->minUDFReadRev),
+                               minUDFReadRev,
                                UDF_MAX_READ_VERSION);
                        ret = -EINVAL;
                        goto error_out;
@@ -2265,11 +2285,7 @@ static int udf_statfs(struct dentry *dentry, struct kstatfs *buf)
        struct logicalVolIntegrityDescImpUse *lvidiu;
        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 
-       if (sbi->s_lvid_bh != NULL)
-               lvidiu = udf_sb_lvidiu(sbi);
-       else
-               lvidiu = NULL;
-
+       lvidiu = udf_sb_lvidiu(sb);
        buf->f_type = UDF_SUPER_MAGIC;
        buf->f_bsize = sb->s_blocksize;
        buf->f_blocks = sbi->s_partmaps[sbi->s_partition].s_partition_len;

diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index ed401e9..1f32c7b 100644 (file)
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -162,7 +162,7 @@ static inline struct udf_sb_info *UDF_SB(struct super_block *sb)
        return sb->s_fs_info;
 }
 
-struct logicalVolIntegrityDescImpUse *udf_sb_lvidiu(struct udf_sb_info *sbi);
+struct logicalVolIntegrityDescImpUse *udf_sb_lvidiu(struct super_block *sb);
 
 int udf_compute_nr_groups(struct super_block *sb, u32 partition);