mirror of
https://github.com/kdave/btrfs-progs
synced 2024-12-29 09:32:24 +00:00
d8f1bd519f
[BUG] Even with chunk_objectid bug fixed, mkfs.btrfs can still caused stack overflow when enabling extent-tree-v2 feature (need experimental features enabled): # ./mkfs.btrfs -f -O extent-tree-v2 ~/test.img btrfs-progs v5.19.1 See http://btrfs.wiki.kernel.org for more information. ERROR: superblock magic doesn't match NOTE: several default settings have changed in version 5.15, please make sure this does not affect your deployments: - DUP for metadata (-m dup) - enabled no-holes (-O no-holes) - enabled free-space-tree (-R free-space-tree) Label: (null) UUID: 205c61e7-f58e-4e8f-9dc2-38724f5c554b Node size: 16384 Sector size: 4096 Filesystem size: 512.00MiB Block group profiles: Data: single 8.00MiB Metadata: DUP 32.00MiB System: DUP 8.00MiB SSD detected: no Zoned device: no ================================================================= [... Skip full ASAN output ...] ==65655==ABORTING [CAUSE] For experimental build, we have unified feature output, but the old buffer size is only 64 bytes, which is too small to cover the new full feature string: extref, skinny-metadata, no-holes, free-space-tree, block-group-tree, extent-tree-v2 Above feature string is already 84 bytes, over the 64 on-stack memory size. This can also be proved by the ASAN output: ==65655==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffc4e03b1d0 at pc 0x7ff0fc05fafe bp 0x7ffc4e03ac60 sp 0x7ffc4e03a408 WRITE of size 17 at 0x7ffc4e03b1d0 thread T0 #0 0x7ff0fc05fafd in __interceptor_strcat /usr/src/debug/gcc/libsanitizer/asan/asan_interceptors.cpp:377 #1 0x55cdb7b06ca5 in parse_features_to_string common/fsfeatures.c:316 #2 0x55cdb7b06ce1 in btrfs_parse_fs_features_to_string common/fsfeatures.c:324 #3 0x55cdb7a37226 in main mkfs/main.c:1783 #4 0x7ff0fbe3c28f (/usr/lib/libc.so.6+0x2328f) #5 0x7ff0fbe3c349 in __libc_start_main (/usr/lib/libc.so.6+0x23349) #6 0x55cdb7a2cb34 in _start ../sysdeps/x86_64/start.S:115 [FIX] Introduce a new macro, BTRFS_FEATURE_STRING_BUF_SIZE, along with a new sanity check helper, btrfs_assert_feature_buf_size(). The problem is I can not find a build time method to verify BTRFS_FEATURE_STRING_BUF_SIZE is large enough to contain all feature names, thus have to go the runtime function to do the BUG_ON() to verify the macro size. Now the minimal buffer size for experimental build is 138 bytes, just bump it to 160 for future expansion. And if further features go beyond that number, mkfs.btrfs/btrfs-convert will immediately crash at that BUG_ON(), so we can definitely detect it. Reviewed-by: Anand Jain <anand.jain@oracle.com> Tested-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|---|---|---|
| .. | ||
| common.c | ||
| common.h | ||
| main.c | ||
| Makefile | ||
| source-ext2.c | ||
| source-ext2.h | ||
| source-fs.c | ||
| source-fs.h | ||
| source-reiserfs.c | ||
| source-reiserfs.h | ||