btrfs-progs: btrfs-progs: Fix read beyond boundary bug in build_roots_info_cache()

This bug is exposed by fsck-test with D=asan, hit by test case 020, with
the following error report:

=================================================================
==10740==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x621000061580 at pc 0x56051f0db6cd bp 0x7ffe170f3e20 sp 0x7ffe170f3e10
READ of size 1 at 0x621000061580 thread T0
    #0 0x56051f0db6cc in btrfs_extent_inline_ref_type /home/adam/btrfs/btrfs-progs/ctree.h:1727
    #1 0x56051f13b669 in build_roots_info_cache /home/adam/btrfs/btrfs-progs/cmds-check.c:14306
    #2 0x56051f13c86a in repair_root_items /home/adam/btrfs/btrfs-progs/cmds-check.c:14450
    #3 0x56051f13ea89 in cmd_check /home/adam/btrfs/btrfs-progs/cmds-check.c:14965
    #4 0x56051efe75bb in main /home/adam/btrfs/btrfs-progs/btrfs.c:302
    #5 0x7f04ddbb0f49 in __libc_start_main (/usr/lib/libc.so.6+0x20f49)
    #6 0x56051efe68c9 in _start (/home/adam/btrfs/btrfs-progs/btrfs+0x5b8c9)

0x621000061580 is located 0 bytes to the right of 4224-byte region [0x621000060500,0x621000061580)
allocated by thread T0 here:
    #0 0x7f04ded50ce1 in __interceptor_calloc /build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cc:70
    #1 0x56051f04685e in __alloc_extent_buffer /home/adam/btrfs/btrfs-progs/extent_io.c:553
    #2 0x56051f047563 in alloc_extent_buffer /home/adam/btrfs/btrfs-progs/extent_io.c:687
    #3 0x56051efff1d1 in btrfs_find_create_tree_block /home/adam/btrfs/btrfs-progs/disk-io.c:187
    #4 0x56051f000133 in read_tree_block /home/adam/btrfs/btrfs-progs/disk-io.c:327
    #5 0x56051efeddb8 in read_node_slot /home/adam/btrfs/btrfs-progs/ctree.c:652
    #6 0x56051effb0d9 in btrfs_next_leaf /home/adam/btrfs/btrfs-progs/ctree.c:2853
    #7 0x56051f13b343 in build_roots_info_cache /home/adam/btrfs/btrfs-progs/cmds-check.c:14267
    #8 0x56051f13c86a in repair_root_items /home/adam/btrfs/btrfs-progs/cmds-check.c:14450
    #9 0x56051f13ea89 in cmd_check /home/adam/btrfs/btrfs-progs/cmds-check.c:14965
    #10 0x56051efe75bb in main /home/adam/btrfs/btrfs-progs/btrfs.c:302
    #11 0x7f04ddbb0f49 in __libc_start_main (/usr/lib/libc.so.6+0x20f49)

It's completely possible that one extent/metadata item has no inline
reference, while build_roots_info_cache() doesn't have such check.

Fix it by checking @iref against item end to avoid such problem.

Issue: #92
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

0 files changed, 0 insertions, 0 deletions