btrfsprogs: Fix use after free in close_ctree
PATCH 1/1 btrfsprogs: Fix use after free in close_ctree
After the roots are closed, root is freed. Yet close_ctree continues to use it. It works generally because no new memory is allocated in the interim, but with glibc malloc perturbing enabled, it crashes every time. This is because root->fs_info points to garbage.
This patch uses the already-cached fs_info variable for the rest of the accesses and fixes the crash.
This issue was reported at:
https://bugzilla.novell.com/show_bug.cgi?id=603620
Signed-off-by Jeff Mahoney <[email protected]>
--- disk-io.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
disk-io.c +5 -5
@@ -971,13 +971,13 @@ int close_ctree(struct btrfs_root *root)if (fs_info->csum_root->node)free_extent_buffer (fs_info->csum_root->node); -if (root->fs_info->log_root_tree) { -if (root->fs_info->log_root_tree->node) -free_extent_buffer (root->fs_info->log_root_tree->node); -free (root->fs_info->log_root_tree); +if (fs_info->log_root_tree) { +if (fs_info->log_root_tree->node) +free_extent_buffer (fs_info->log_root_tree->node); +free (fs_info->log_root_tree); } -close_all_devices (root->fs_info); +close_all_devices (fs_info);extent_io_tree_cleanup (&fs_info->extent_cache);extent_io_tree_cleanup (&fs_info->free_space_cache);extent_io_tree_cleanup (&fs_info->block_group_cache);
Signature · 2 lines
Jeff Mahoney SUSE Labs