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-rw-r--r--fs/exfat/dir.c12
-rw-r--r--fs/exfat/fatent.c10
-rw-r--r--fs/exfat/file.c5
-rw-r--r--fs/exfat/namei.c5
-rw-r--r--fs/exfat/super.c32
5 files changed, 50 insertions, 14 deletions
diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index 3103b932b674..ee060e26f51d 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -996,6 +996,7 @@ int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
struct exfat_hint_femp candi_empty;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
int num_entries = exfat_calc_num_entries(p_uniname);
+ unsigned int clu_count = 0;
if (num_entries < 0)
return num_entries;
@@ -1133,6 +1134,10 @@ rewind:
} else {
if (exfat_get_next_cluster(sb, &clu.dir))
return -EIO;
+
+ /* break if the cluster chain includes a loop */
+ if (unlikely(++clu_count > EXFAT_DATA_CLUSTER_COUNT(sbi)))
+ goto not_found;
}
}
@@ -1195,6 +1200,7 @@ int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
int i, count = 0;
int dentries_per_clu;
unsigned int entry_type;
+ unsigned int clu_count = 0;
struct exfat_chain clu;
struct exfat_dentry *ep;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
@@ -1227,6 +1233,12 @@ int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
} else {
if (exfat_get_next_cluster(sb, &(clu.dir)))
return -EIO;
+
+ if (unlikely(++clu_count > sbi->used_clusters)) {
+ exfat_fs_error(sb, "FAT or bitmap is corrupted");
+ return -EIO;
+ }
+
}
}
diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c
index 23065f948ae7..232cc7f8ab92 100644
--- a/fs/exfat/fatent.c
+++ b/fs/exfat/fatent.c
@@ -490,5 +490,15 @@ int exfat_count_num_clusters(struct super_block *sb,
}
*ret_count = count;
+
+ /*
+ * since exfat_count_used_clusters() is not called, sbi->used_clusters
+ * cannot be used here.
+ */
+ if (unlikely(i == sbi->num_clusters && clu != EXFAT_EOF_CLUSTER)) {
+ exfat_fs_error(sb, "The cluster chain has a loop");
+ return -EIO;
+ }
+
return 0;
}
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 6b82497572b4..538d2b6ac2ec 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -622,9 +622,8 @@ static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
if (pos > valid_size)
pos = valid_size;
- if (iocb_is_dsync(iocb) && iocb->ki_pos > pos) {
- ssize_t err = vfs_fsync_range(file, pos, iocb->ki_pos - 1,
- iocb->ki_flags & IOCB_SYNC);
+ if (iocb->ki_pos > pos) {
+ ssize_t err = generic_write_sync(iocb, iocb->ki_pos - pos);
if (err < 0)
return err;
}
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index fede0283d6e2..f5f1c4e8a29f 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -890,6 +890,7 @@ static int exfat_check_dir_empty(struct super_block *sb,
{
int i, dentries_per_clu;
unsigned int type;
+ unsigned int clu_count = 0;
struct exfat_chain clu;
struct exfat_dentry *ep;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
@@ -926,6 +927,10 @@ static int exfat_check_dir_empty(struct super_block *sb,
} else {
if (exfat_get_next_cluster(sb, &(clu.dir)))
return -EIO;
+
+ /* break if the cluster chain includes a loop */
+ if (unlikely(++clu_count > EXFAT_DATA_CLUSTER_COUNT(sbi)))
+ break;
}
}
diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index ea5c1334a214..8926e63f5bb7 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -341,13 +341,12 @@ static void exfat_hash_init(struct super_block *sb)
INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
}
-static int exfat_read_root(struct inode *inode)
+static int exfat_read_root(struct inode *inode, struct exfat_chain *root_clu)
{
struct super_block *sb = inode->i_sb;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct exfat_inode_info *ei = EXFAT_I(inode);
- struct exfat_chain cdir;
- int num_subdirs, num_clu = 0;
+ int num_subdirs;
exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
ei->entry = -1;
@@ -360,12 +359,9 @@ static int exfat_read_root(struct inode *inode)
ei->hint_stat.clu = sbi->root_dir;
ei->hint_femp.eidx = EXFAT_HINT_NONE;
- exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
- if (exfat_count_num_clusters(sb, &cdir, &num_clu))
- return -EIO;
- i_size_write(inode, num_clu << sbi->cluster_size_bits);
+ i_size_write(inode, EXFAT_CLU_TO_B(root_clu->size, sbi));
- num_subdirs = exfat_count_dir_entries(sb, &cdir);
+ num_subdirs = exfat_count_dir_entries(sb, root_clu);
if (num_subdirs < 0)
return -EIO;
set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
@@ -578,7 +574,8 @@ static int exfat_verify_boot_region(struct super_block *sb)
}
/* mount the file system volume */
-static int __exfat_fill_super(struct super_block *sb)
+static int __exfat_fill_super(struct super_block *sb,
+ struct exfat_chain *root_clu)
{
int ret;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
@@ -595,6 +592,18 @@ static int __exfat_fill_super(struct super_block *sb)
goto free_bh;
}
+ /*
+ * Call exfat_count_num_cluster() before searching for up-case and
+ * bitmap directory entries to avoid infinite loop if they are missing
+ * and the cluster chain includes a loop.
+ */
+ exfat_chain_set(root_clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+ ret = exfat_count_num_clusters(sb, root_clu, &root_clu->size);
+ if (ret) {
+ exfat_err(sb, "failed to count the number of clusters in root");
+ goto free_bh;
+ }
+
ret = exfat_create_upcase_table(sb);
if (ret) {
exfat_err(sb, "failed to load upcase table");
@@ -627,6 +636,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
struct exfat_sb_info *sbi = sb->s_fs_info;
struct exfat_mount_options *opts = &sbi->options;
struct inode *root_inode;
+ struct exfat_chain root_clu;
int err;
if (opts->allow_utime == (unsigned short)-1)
@@ -645,7 +655,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
- err = __exfat_fill_super(sb);
+ err = __exfat_fill_super(sb, &root_clu);
if (err) {
exfat_err(sb, "failed to recognize exfat type");
goto check_nls_io;
@@ -680,7 +690,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
root_inode->i_ino = EXFAT_ROOT_INO;
inode_set_iversion(root_inode, 1);
- err = exfat_read_root(root_inode);
+ err = exfat_read_root(root_inode, &root_clu);
if (err) {
exfat_err(sb, "failed to initialize root inode");
goto put_inode;
generated by cgit (git 2.34.1) at 2025-08-05 22:23:47 +0000