From 5f855daf6487b64eae1f201483b5830f42b2e9bb 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 commit 3ebacb05044f82c5f0bb456a894eb9dc57d0ed90 upstream. 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 Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- 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 a790821..ea3d1ca 100644 --- a/fs/hpfs/map.c +++ b/fs/hpfs/map.c @@ -17,7 +17,8 @@ unsigned int *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 54f6ecc..0bf578d 100644 --- a/fs/hpfs/super.c +++ b/fs/hpfs/super.c @@ -552,7 +552,13 @@ 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; -- 2.7.4