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From: Kees C. <kee...@ch...> - 2018-06-26 17:52:37
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In the quest to remove all stack VLA usage from the kernel[1], this uses the maximum size needed on the stack and adds a sanity check for robustness: index.block_size cannot be larger than PAGE_SIZE nor less than NTFS_BLOCK_SIZE. [1] https://lkml.kernel.org/r/CA+...@ma... Cc: Anton Altaparmakov <an...@tu...> Cc: lin...@li... Signed-off-by: Kees Cook <kee...@ch...> --- fs/ntfs/aops.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c index 3a2e509c77c5..58dadff3e0e0 100644 --- a/fs/ntfs/aops.c +++ b/fs/ntfs/aops.c @@ -926,7 +926,7 @@ static int ntfs_write_mst_block(struct page *page, ntfs_volume *vol = ni->vol; u8 *kaddr; unsigned int rec_size = ni->itype.index.block_size; - ntfs_inode *locked_nis[PAGE_SIZE / rec_size]; + ntfs_inode *locked_nis[PAGE_SIZE / NTFS_BLOCK_SIZE]; struct buffer_head *bh, *head, *tbh, *rec_start_bh; struct buffer_head *bhs[MAX_BUF_PER_PAGE]; runlist_element *rl; @@ -935,6 +935,9 @@ static int ntfs_write_mst_block(struct page *page, bool sync, is_mft, page_is_dirty, rec_is_dirty; unsigned char bh_size_bits; + if (WARN_ON(rec_size < NTFS_BLOCK_SIZE)) + return -EINVAL; + ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index " "0x%lx.", vi->i_ino, ni->type, page->index); BUG_ON(!NInoNonResident(ni)); -- 2.17.1 |
