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authorBaokun Li <libaokun1@huawei.com>2022-11-01 15:33:43 +0800
committerAndrew Morton <akpm@linux-foundation.org>2022-11-18 13:55:09 -0800
commitc7e8d3279c984e41165a7b510759bd1771ac3941 (patch)
treeb420ddcf8e0aebc1d109f6ef642b94dc5458ffea /fs/squashfs
parent13b6269dd022aaa69ca8d1df374ab327504121cf (diff)
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.c3
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 {