exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helper
That stuff can be accessed by ->d_hash()/->d_compare(); as it is, we have
a hard-to-hit UAF if rcu pathwalk manages to get into ->d_hash() on a filesystem
that is in process of getting shut down.
Besides, having nls and upcase table cleanup moved from ->put_super() towards
the place where sbi is freed makes for simpler failure exits.
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c
index 705710f..afdf13c 100644
--- a/fs/exfat/nls.c
+++ b/fs/exfat/nls.c
@@ -655,7 +655,6 @@ static int exfat_load_upcase_table(struct super_block *sb,
unsigned int sect_size = sb->s_blocksize;
unsigned int i, index = 0;
u32 chksum = 0;
- int ret;
unsigned char skip = false;
unsigned short *upcase_table;
@@ -673,8 +672,7 @@ static int exfat_load_upcase_table(struct super_block *sb,
if (!bh) {
exfat_err(sb, "failed to read sector(0x%llx)",
(unsigned long long)sector);
- ret = -EIO;
- goto free_table;
+ return -EIO;
}
sector++;
for (i = 0; i < sect_size && index <= 0xFFFF; i += 2) {
@@ -701,15 +699,12 @@ static int exfat_load_upcase_table(struct super_block *sb,
exfat_err(sb, "failed to load upcase table (idx : 0x%08x, chksum : 0x%08x, utbl_chksum : 0x%08x)",
index, chksum, utbl_checksum);
- ret = -EINVAL;
-free_table:
- exfat_free_upcase_table(sbi);
- return ret;
+ return -EINVAL;
}
static int exfat_load_default_upcase_table(struct super_block *sb)
{
- int i, ret = -EIO;
+ int i;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
unsigned char skip = false;
unsigned short uni = 0, *upcase_table;
@@ -740,8 +735,7 @@ static int exfat_load_default_upcase_table(struct super_block *sb)
return 0;
/* FATAL error: default upcase table has error */
- exfat_free_upcase_table(sbi);
- return ret;
+ return -EIO;
}
int exfat_create_upcase_table(struct super_block *sb)
