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| author | Baokun Li <libaokun1@huawei.com> | 2022-11-01 15:33:43 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-11-18 13:55:09 -0800 |
| commit | c7e8d3279c984e41165a7b510759bd1771ac3941 (patch) | |
| tree | b420ddcf8e0aebc1d109f6ef642b94dc5458ffea /fs/squashfs | |
| parent | 13b6269dd022aaa69ca8d1df374ab327504121cf (diff) | |
| download | linux-c7e8d3279c984e41165a7b510759bd1771ac3941.tar.gz linux-c7e8d3279c984e41165a7b510759bd1771ac3941.tar.bz2 linux-c7e8d3279c984e41165a7b510759bd1771ac3941.zip | |
squashfs: fix null-ptr-deref in squashfs_fill_super
When squashfs_read_table() returns an error or `sb->s_magic !=
SQUASHFS_MAGIC`, enters the error branch and calls
msblk->thread_ops->destroy(msblk) to destroy msblk. However,
msblk->thread_ops has not been initialized. Therefore, the following
problem is triggered:
==================================================================
BUG: KASAN: null-ptr-deref in squashfs_fill_super+0xe7a/0x13b0
Read of size 8 at addr 0000000000000008 by task swapper/0/1
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.1.0-rc3-next-20221031 #367
Call Trace:
<TASK>
dump_stack_lvl+0x73/0x9f
print_report+0x743/0x759
kasan_report+0xc0/0x120
__asan_load8+0xd3/0x140
squashfs_fill_super+0xe7a/0x13b0
get_tree_bdev+0x27b/0x450
squashfs_get_tree+0x19/0x30
vfs_get_tree+0x49/0x150
path_mount+0xaae/0x1350
init_mount+0xad/0x100
do_mount_root+0xbc/0x1d0
mount_block_root+0x173/0x316
mount_root+0x223/0x236
prepare_namespace+0x1eb/0x237
kernel_init_freeable+0x528/0x576
kernel_init+0x29/0x250
ret_from_fork+0x1f/0x30
</TASK>
==================================================================
To solve this issue, msblk->thread_ops is initialized immediately after
msblk is assigned a value.
Link: https://lkml.kernel.org/r/20221101073343.3961562-1-libaokun1@huawei.com
Fixes: b0645770d3c7 ("squashfs: add the mount parameter theads=<single|multi|percpu>")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Yu Kuai <yukuai3@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/squashfs')
| -rw-r--r-- | fs/squashfs/super.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c index 1e428ca9414e..7d5265a39d20 100644 --- a/fs/squashfs/super.c +++ b/fs/squashfs/super.c @@ -197,6 +197,7 @@ static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc) return -ENOMEM; } msblk = sb->s_fs_info; + msblk->thread_ops = opts->thread_ops; msblk->panic_on_errors = (opts->errors == Opt_errors_panic); @@ -231,7 +232,7 @@ static int squashfs_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_bdev); goto failed_mount; } - msblk->thread_ops = opts->thread_ops; + if (opts->thread_num == 0) { msblk->max_thread_num = msblk->thread_ops->max_decompressors(); } else { |