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authorQu Wenruo <wqu@suse.com>2017-11-06 10:43:18 +0800
committerDavid Sterba <dsterba@suse.com>2017-11-27 17:01:11 +0100
commiteae8d82529dd9820e206ecba0047b806c4410e65 (patch)
tree4ffa64543581d15ddabb694d74ca272e0ec220fa /fs/btrfs/compression.h
parentb77000ed558daa3bef0899d29bf171b8c9b5e6a8 (diff)
downloadlinux-eae8d82529dd9820e206ecba0047b806c4410e65.tar.bz2
btrfs: Fix wild memory access in compression level parser
[BUG] Kernel panic when mounting with "-o compress" mount option. KASAN will report like: ------ ================================================================== BUG: KASAN: wild-memory-access in strncmp+0x31/0xc0 Read of size 1 at addr d86735fce994f800 by task mount/662 ... Call Trace: dump_stack+0xe3/0x175 kasan_report+0x163/0x370 __asan_load1+0x47/0x50 strncmp+0x31/0xc0 btrfs_compress_str2level+0x20/0x70 [btrfs] btrfs_parse_options+0xff4/0x1870 [btrfs] open_ctree+0x2679/0x49f0 [btrfs] btrfs_mount+0x1b7f/0x1d30 [btrfs] mount_fs+0x49/0x190 vfs_kern_mount.part.29+0xba/0x280 vfs_kern_mount+0x13/0x20 btrfs_mount+0x31e/0x1d30 [btrfs] mount_fs+0x49/0x190 vfs_kern_mount.part.29+0xba/0x280 do_mount+0xaad/0x1a00 SyS_mount+0x98/0xe0 entry_SYSCALL_64_fastpath+0x1f/0xbe ------ [Cause] For 'compress' and 'compress_force' options, its token doesn't expect any parameter so its args[0] contains uninitialized data. Accessing args[0] will cause above wild memory access. [Fix] For Opt_compress and Opt_compress_force, set compression level to the default. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ set the default in advance ] Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/compression.h')
-rw-r--r--fs/btrfs/compression.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 93c5b82ae97e..0868cc554f14 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -34,6 +34,8 @@
/* Maximum size of data before compression */
#define BTRFS_MAX_UNCOMPRESSED (SZ_128K)
+#define BTRFS_ZLIB_DEFAULT_LEVEL 3
+
struct compressed_bio {
/* number of bios pending for this compressed extent */
refcount_t pending_bios;