From 3ebacb05044f82c5f0bb456a894eb9dc57d0ed90 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 4 Jul 2013 18:42:29 +0200 Subject: [PATCH] hpfs: better test for errors The test if bitmap access is out of bound could errorneously pass if the device size is divisible by 16384 sectors and we are asking for one bitmap after the end. Check for invalid size in the superblock. Invalid size could cause integer overflows in the rest of the code. Signed-off-by: Mikulas Patocka Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- fs/hpfs/map.c | 3 ++- fs/hpfs/super.c | 8 +++++++- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/hpfs/map.c b/fs/hpfs/map.c index 4acb19d78359..803d3da3a0fe 100644 --- a/fs/hpfs/map.c +++ b/fs/hpfs/map.c @@ -17,7 +17,8 @@ __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block, struct quad_buffer_head *qbh, char *id) { secno sec; - if (hpfs_sb(s)->sb_chk) if (bmp_block * 16384 > hpfs_sb(s)->sb_fs_size) { + unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14; + if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) { hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id); return NULL; } diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c index a0617e706957..962e90c37aec 100644 --- a/fs/hpfs/super.c +++ b/fs/hpfs/super.c @@ -558,7 +558,13 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent) sbi->sb_cp_table = NULL; sbi->sb_c_bitmap = -1; sbi->sb_max_fwd_alloc = 0xffffff; - + + if (sbi->sb_fs_size >= 0x80000000) { + hpfs_error(s, "invalid size in superblock: %08x", + (unsigned)sbi->sb_fs_size); + goto bail4; + } + /* Load bitmap directory */ if (!(sbi->sb_bmp_dir = hpfs_load_bitmap_directory(s, le32_to_cpu(superblock->bitmaps)))) goto bail4; -- 2.20.1