2021-05-29 08:17:27

by Yang Yingliang

Subject: [PATCH -next 1/3] cifsd: fix memleak in ksmbd_vfs_stream_write()

Before assigning wbuf to stream_buf, memory allocate in
ksmbd_vfs_getcasexattr() need be freed.

Fixes: f44158485826 ("cifsd: add file operations")
Signed-off-by: Yang Yingliang <[email protected]>
---
fs/cifsd/vfs.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/cifsd/vfs.c b/fs/cifsd/vfs.c
index 291953eff5fa..9057b30278b9 100644
--- a/fs/cifsd/vfs.c
+++ b/fs/cifsd/vfs.c
@@ -429,6 +429,7 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos,

if (v_len > 0)
memcpy(wbuf, stream_buf, v_len);
+ kfree(stream_buf);
stream_buf = wbuf;
}

--
2.25.1

2021-05-29 08:17:37

by Yang Yingliang

Subject: [PATCH -next 2/3] cifsd: fix memleak in ksmbd_vfs_stream_read()

Before ksmbd_vfs_stream_read() return, memory allocate in
ksmbd_vfs_getcasexattr() need be freed.

Fixes: f44158485826 ("cifsd: add file operations")
Signed-off-by: Yang Yingliang <[email protected]>
---
fs/cifsd/vfs.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/cifsd/vfs.c b/fs/cifsd/vfs.c
index 9057b30278b9..97d5584ec870 100644
--- a/fs/cifsd/vfs.c
+++ b/fs/cifsd/vfs.c
@@ -290,6 +290,7 @@ static int ksmbd_vfs_stream_read(struct ksmbd_file *fp, char *buf, loff_t *pos,
}

memcpy(buf, &stream_buf[*pos], count);
+ kfree(stream_buf);
return v_len > count ? count : v_len;
}

--
2.25.1

2021-05-29 08:18:39

by Yang Yingliang

Subject: [PATCH -next 3/3] cifsd: check return value of ksmbd_vfs_getcasexattr() correctly

If ksmbd_vfs_getcasexattr() returns -ENOMEM, stream_buf is NULL,
it will cause null-ptr-deref when using it to copy memory. So we
need check the return value of ksmbd_vfs_getcasexattr() by comparing
with 0.

Fixes: f44158485826 ("cifsd: add file operations")
Signed-off-by: Yang Yingliang <[email protected]>
---
fs/cifsd/vfs.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/cifsd/vfs.c b/fs/cifsd/vfs.c
index 97d5584ec870..45ba30f1f2d2 100644
--- a/fs/cifsd/vfs.c
+++ b/fs/cifsd/vfs.c
@@ -274,7 +274,6 @@ static int ksmbd_vfs_stream_read(struct ksmbd_file *fp, char *buf, loff_t *pos,
{
ssize_t v_len;
char *stream_buf = NULL;
- int err;

ksmbd_debug(VFS, "read stream data pos : %llu, count : %zd\n",
*pos, count);
@@ -283,10 +282,9 @@ static int ksmbd_vfs_stream_read(struct ksmbd_file *fp, char *buf, loff_t *pos,
fp->stream.name,
fp->stream.size,
&stream_buf);
- if (v_len == -ENOENT) {
+ if ((int)v_len < 0) {
ksmbd_err("not found stream in xattr : %zd\n", v_len);
- err = -ENOENT;
- return err;
+ return (int)v_len;
}

memcpy(buf, &stream_buf[*pos], count);
@@ -415,9 +413,9 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos,
fp->stream.name,
fp->stream.size,
&stream_buf);
- if (v_len == -ENOENT) {
+ if ((int)v_len < 0) {
ksmbd_err("not found stream in xattr : %zd\n", v_len);
- err = -ENOENT;
+ err = (int)v_len;
goto out;
}

--
2.25.1

2021-05-29 14:15:34

by Hyunchul Lee

Subject: Re: [PATCH -next 3/3] cifsd: check return value of ksmbd_vfs_getcasexattr() correctly

Hi Yang,

2021년 5월 29일 (토) 오후 5:16, Yang Yingliang <[email protected]>님이 작성:
>
> If ksmbd_vfs_getcasexattr() returns -ENOMEM, stream_buf is NULL,
> it will cause null-ptr-deref when using it to copy memory. So we
> need check the return value of ksmbd_vfs_getcasexattr() by comparing
> with 0.
>
> Fixes: f44158485826 ("cifsd: add file operations")
> Signed-off-by: Yang Yingliang <[email protected]>
> ---
> fs/cifsd/vfs.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/fs/cifsd/vfs.c b/fs/cifsd/vfs.c
> index 97d5584ec870..45ba30f1f2d2 100644
> --- a/fs/cifsd/vfs.c
> +++ b/fs/cifsd/vfs.c
> @@ -274,7 +274,6 @@ static int ksmbd_vfs_stream_read(struct ksmbd_file *fp, char *buf, loff_t *pos,
> {
> ssize_t v_len;
> char *stream_buf = NULL;
> - int err;
>
> ksmbd_debug(VFS, "read stream data pos : %llu, count : %zd\n",
> *pos, count);
> @@ -283,10 +282,9 @@ static int ksmbd_vfs_stream_read(struct ksmbd_file *fp, char *buf, loff_t *pos,
> fp->stream.name,
> fp->stream.size,
> &stream_buf);
> - if (v_len == -ENOENT) {
> + if ((int)v_len < 0) {

because ksmbd_vfs_getcasexattr can return 0, 0 has to be handled.

Thanks,
Hyunchul

> ksmbd_err("not found stream in xattr : %zd\n", v_len);
> - err = -ENOENT;
> - return err;
> + return (int)v_len;
> }
>
> memcpy(buf, &stream_buf[*pos], count);
> @@ -415,9 +413,9 @@ static int ksmbd_vfs_stream_write(struct ksmbd_file *fp, char *buf, loff_t *pos,
> fp->stream.name,
> fp->stream.size,
> &stream_buf);
> - if (v_len == -ENOENT) {
> + if ((int)v_len < 0) {
> ksmbd_err("not found stream in xattr : %zd\n", v_len);
> - err = -ENOENT;
> + err = (int)v_len;
> goto out;
> }
>
> --
> 2.25.1
>

2021-05-31 01:11:44

by Namjae Jeon

Subject: RE: [PATCH -next 2/3] cifsd: fix memleak in ksmbd_vfs_stream_read()

> Before ksmbd_vfs_stream_read() return, memory allocate in
> ksmbd_vfs_getcasexattr() need be freed.
>
> Fixes: f44158485826 ("cifsd: add file operations")
> Signed-off-by: Yang Yingliang <[email protected]>
I will apply, Thanks for your patch!

2021-05-31 01:12:56

by Namjae Jeon

Subject: RE: [PATCH -next 1/3] cifsd: fix memleak in ksmbd_vfs_stream_write()

> Before assigning wbuf to stream_buf, memory allocate in
> ksmbd_vfs_getcasexattr() need be freed.
>
> Fixes: f44158485826 ("cifsd: add file operations")
> Signed-off-by: Yang Yingliang <[email protected]>
I will apply, Thanks for your patch!