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authorOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>2017-03-09 16:17:37 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-03-09 17:01:10 -0800
commitc0d0e351285161a515396b7b1ee53ec9ffd97e3c (patch)
tree10a446f71ea3e4ec0e82abadbda61bbdb79bdac1
parentca5b58ea3db88b5e69ba2a1f6bc3cf239cdcc64f (diff)
fat: fix using uninitialized fields of fat_inode/fsinfo_inode
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 <moreno.bartalucci@tecnorama.it> Tested-by: Moreno Bartalucci <moreno.bartalucci@tecnorama.it> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/fat/inode.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 338d2f73eb29..a2c05f2ada6d 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -1359,6 +1359,16 @@ 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 msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
@@ -1803,12 +1813,13 @@ 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);

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