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Message-ID: <tencent_C54679498DEEC46ED40C8BA7F386D352D606@qq.com>
From: Edward Adam Davis <eadavis@qq.com>
To: syzbot+65f53dd6a0f7ad64c0cb@syzkaller.appspotmail.com
Cc: linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: [PATCH] fs/hfsplus: fix uninit-value in hfs_find_1st_rec_by_cnid
Date: Fri, 22 Mar 2024 08:31:08 +0800
In-Reply-To: <0000000000008fd9bc061428179e@google.com>
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[syzbot reported]
BUG: KMSAN: uninit-value in hfs_find_1st_rec_by_cnid+0x27a/0x3f0 fs/hfsplus/bfind.c:78
 hfs_find_1st_rec_by_cnid+0x27a/0x3f0 fs/hfsplus/bfind.c:78
 __hfsplus_brec_find+0x26f/0x7b0 fs/hfsplus/bfind.c:135
 hfsplus_brec_find+0x445/0x970 fs/hfsplus/bfind.c:195
 hfsplus_find_attr+0x30c/0x390
 hfsplus_listxattr+0x586/0x1a60 fs/hfsplus/xattr.c:708
 vfs_listxattr fs/xattr.c:493 [inline]
 listxattr+0x1f3/0x6b0 fs/xattr.c:840
 path_listxattr fs/xattr.c:864 [inline]
 __do_sys_listxattr fs/xattr.c:876 [inline]
 __se_sys_listxattr fs/xattr.c:873 [inline]
 __x64_sys_listxattr+0x16b/0x2f0 fs/xattr.c:873
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3804 [inline]
 slab_alloc_node mm/slub.c:3845 [inline]
 __do_kmalloc_node mm/slub.c:3965 [inline]
 __kmalloc+0x6e4/0x1000 mm/slub.c:3979
 kmalloc include/linux/slab.h:632 [inline]
 hfsplus_find_init+0x91/0x250 fs/hfsplus/bfind.c:21
 hfsplus_listxattr+0x44a/0x1a60 fs/hfsplus/xattr.c:695
 vfs_listxattr fs/xattr.c:493 [inline]
 listxattr+0x1f3/0x6b0 fs/xattr.c:840
 path_listxattr fs/xattr.c:864 [inline]
 __do_sys_listxattr fs/xattr.c:876 [inline]
 __se_sys_listxattr fs/xattr.c:873 [inline]
 __x64_sys_listxattr+0x16b/0x2f0 fs/xattr.c:873
 do_syscall_64+0xd5/0x1f0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
[Fix]
Let's clear all search_key fields at alloc time.

Reported-and-tested-by: syzbot+65f53dd6a0f7ad64c0cb@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 fs/hfsplus/bfind.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/hfsplus/bfind.c b/fs/hfsplus/bfind.c
index ca2ba8c9f82e..b939dc879dac 100644
--- a/fs/hfsplus/bfind.c
+++ b/fs/hfsplus/bfind.c
@@ -18,7 +18,7 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
 
 	fd->tree = tree;
 	fd->bnode = NULL;
-	ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
+	ptr = kzalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
 	if (!ptr)
 		return -ENOMEM;
 	fd->search_key = ptr;
-- 
2.43.0