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From: Chao Yu <chao@kernel.org>
To: jaegeuk@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net
Subject: [f2fs-dev] [PATCH v2] f2fs: fix uninit-value in f2fs_lookup
Date: Sat, 26 Sep 2020 07:38:19 +0800	[thread overview]
Message-ID: <20200925233819.5359-1-chao@kernel.org> (raw)

From: Chao Yu <yuchao0@huawei.com>

As syzbot reported:

Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219
 f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503
 lookup_open fs/namei.c:3082 [inline]
 open_last_lookups fs/namei.c:3177 [inline]
 path_openat+0x2729/0x6a90 fs/namei.c:3365
 do_filp_open+0x2b8/0x710 fs/namei.c:3395
 do_sys_openat2+0xa88/0x1140 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_compat_sys_openat fs/open.c:1242 [inline]
 __se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240
 __ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240
 do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
 __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139
 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

In f2fs_lookup(), @res_page could be used before being initialized,
because in __f2fs_find_entry(), once F2FS_I(dir)->i_current_depth was
been fuzzed to zero, then @res_page will never be initialized, causing
this kmsan warning, relocating @res_page initialization place to fix
this bug.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
v2:
- remove *res_page assignment in a loop.
 fs/f2fs/dir.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 069f498af1e3..ceb4431b5669 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -357,16 +357,15 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
 	unsigned int max_depth;
 	unsigned int level;
 
+	*res_page = NULL;
+
 	if (f2fs_has_inline_dentry(dir)) {
-		*res_page = NULL;
 		de = f2fs_find_in_inline_dir(dir, fname, res_page);
 		goto out;
 	}
 
-	if (npages == 0) {
-		*res_page = NULL;
+	if (npages == 0)
 		goto out;
-	}
 
 	max_depth = F2FS_I(dir)->i_current_depth;
 	if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
@@ -377,7 +376,6 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
 	}
 
 	for (level = 0; level < max_depth; level++) {
-		*res_page = NULL;
 		de = find_in_level(dir, level, fname, res_page);
 		if (de || IS_ERR(*res_page))
 			break;
-- 
2.22.0



_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

WARNING: multiple messages have this Message-ID (diff)
From: Chao Yu <chao@kernel.org>
To: jaegeuk@kernel.org
Cc: linux-f2fs-devel@lists.sourceforge.net,
	linux-kernel@vger.kernel.org, Chao Yu <yuchao0@huawei.com>
Subject: [PATCH v2] f2fs: fix uninit-value in f2fs_lookup
Date: Sat, 26 Sep 2020 07:38:19 +0800	[thread overview]
Message-ID: <20200925233819.5359-1-chao@kernel.org> (raw)

From: Chao Yu <yuchao0@huawei.com>

As syzbot reported:

Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219
 f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503
 lookup_open fs/namei.c:3082 [inline]
 open_last_lookups fs/namei.c:3177 [inline]
 path_openat+0x2729/0x6a90 fs/namei.c:3365
 do_filp_open+0x2b8/0x710 fs/namei.c:3395
 do_sys_openat2+0xa88/0x1140 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_compat_sys_openat fs/open.c:1242 [inline]
 __se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240
 __ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240
 do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
 __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139
 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

In f2fs_lookup(), @res_page could be used before being initialized,
because in __f2fs_find_entry(), once F2FS_I(dir)->i_current_depth was
been fuzzed to zero, then @res_page will never be initialized, causing
this kmsan warning, relocating @res_page initialization place to fix
this bug.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
v2:
- remove *res_page assignment in a loop.
 fs/f2fs/dir.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 069f498af1e3..ceb4431b5669 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -357,16 +357,15 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
 	unsigned int max_depth;
 	unsigned int level;
 
+	*res_page = NULL;
+
 	if (f2fs_has_inline_dentry(dir)) {
-		*res_page = NULL;
 		de = f2fs_find_in_inline_dir(dir, fname, res_page);
 		goto out;
 	}
 
-	if (npages == 0) {
-		*res_page = NULL;
+	if (npages == 0)
 		goto out;
-	}
 
 	max_depth = F2FS_I(dir)->i_current_depth;
 	if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
@@ -377,7 +376,6 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
 	}
 
 	for (level = 0; level < max_depth; level++) {
-		*res_page = NULL;
 		de = find_in_level(dir, level, fname, res_page);
 		if (de || IS_ERR(*res_page))
 			break;
-- 
2.22.0


             reply	other threads:[~2020-09-25 23:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25 23:38 Chao Yu [this message]
2020-09-25 23:38 ` [PATCH v2] f2fs: fix uninit-value in f2fs_lookup Chao Yu
2020-09-28 21:49 ` [f2fs-dev] " Eric Biggers
2020-09-28 21:49   ` Eric Biggers

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