[PATCH 3.10 171/268] fat: fix using uninitialized fields of fat_inode/fsinfo_inode
From: Willy Tarreau <w@1wt.eu>
Date: 2017-06-19 19:26:58
Also in:
lkml
Subsystem:
filesystems (vfs and infrastructure), the rest, vfat/fat/msdos filesystem · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds, OGAWA Hirofumi
From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> commit c0d0e351285161a515396b7b1ee53ec9ffd97e3c upstream. Recently fallocate patch was merged and it uses MSDOS_I(inode)->mmu_private at fat_evict_inode(). However, fat_inode/fsinfo_inode that was introduced in past didn't initialize MSDOS_I(inode) properly. With those combinations, it became the cause of accessing random entry in FAT area. Link: http://lkml.kernel.org/r/87pohrj4i8.fsf@mail.parknet.co.jp Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Reported-by: Moreno Bartalucci <redacted> Tested-by: Moreno Bartalucci <redacted> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Willy Tarreau <w@1wt.eu> --- fs/fat/inode.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 5d4513c..04708fa 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c@@ -1193,6 +1193,16 @@ out: return 0; } +static void fat_dummy_inode_init(struct inode *inode) +{ + /* Initialize this dummy inode to work as no-op. */ + MSDOS_I(inode)->mmu_private = 0; + MSDOS_I(inode)->i_start = 0; + MSDOS_I(inode)->i_logstart = 0; + MSDOS_I(inode)->i_attrs = 0; + MSDOS_I(inode)->i_pos = 0; +} + static int fat_read_root(struct inode *inode) { struct super_block *sb = inode->i_sb;
@@ -1503,12 +1513,13 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, fat_inode = new_inode(sb); if (!fat_inode) goto out_fail; - MSDOS_I(fat_inode)->i_pos = 0; + fat_dummy_inode_init(fat_inode); sbi->fat_inode = fat_inode; fsinfo_inode = new_inode(sb); if (!fsinfo_inode) goto out_fail; + fat_dummy_inode_init(fsinfo_inode); fsinfo_inode->i_ino = MSDOS_FSINFO_INO; sbi->fsinfo_inode = fsinfo_inode; insert_inode_hash(fsinfo_inode);
--
2.8.0.rc2.1.gbe9624a