2019-07-26 03:39:07

by Jia-Ju Bai

Subject: [PATCH 3/3] fs: ocfs2: Fix a possible null-pointer dereference in ocfs2_info_scan_inode_alloc()

In ocfs2_info_scan_inode_alloc(), there is an if statement on line 283
to check whether inode_alloc is NULL:
if (inode_alloc)

When inode_alloc is NULL, it is used on line 287:
ocfs2_inode_lock(inode_alloc, &bh, 0);
ocfs2_inode_lock_full_nested(inode, ...)
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

Thus, a possible null-pointer dereference may occur.

To fix this bug, inode_alloc is checked on line 286.

This bug is found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
fs/ocfs2/ioctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index d6f7b299eb23..efeea208fdeb 100644
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -283,7 +283,7 @@ static int ocfs2_info_scan_inode_alloc(struct ocfs2_super *osb,
if (inode_alloc)
inode_lock(inode_alloc);

- if (o2info_coherent(&fi->ifi_req)) {
+ if (inode_alloc && o2info_coherent(&fi->ifi_req)) {
status = ocfs2_inode_lock(inode_alloc, &bh, 0);
if (status < 0) {
mlog_errno(status);
--
2.17.0

2019-07-26 09:40:40

by Joseph Qi

Subject: Re: [PATCH 3/3] fs: ocfs2: Fix a possible null-pointer dereference in ocfs2_info_scan_inode_alloc()

On 19/7/26 11:37, Jia-Ju Bai wrote:
> In ocfs2_info_scan_inode_alloc(), there is an if statement on line 283
> to check whether inode_alloc is NULL:
> if (inode_alloc)
>
> When inode_alloc is NULL, it is used on line 287:
> ocfs2_inode_lock(inode_alloc, &bh, 0);
> ocfs2_inode_lock_full_nested(inode, ...)
> struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
>
> Thus, a possible null-pointer dereference may occur.
>
> To fix this bug, inode_alloc is checked on line 286.
>
> This bug is found by a static analysis tool STCheck written by us.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>

Looks good.
Reviewed-by: Joseph Qi <[email protected]>
> ---
> fs/ocfs2/ioctl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
> index d6f7b299eb23..efeea208fdeb 100644
> --- a/fs/ocfs2/ioctl.c
> +++ b/fs/ocfs2/ioctl.c
> @@ -283,7 +283,7 @@ static int ocfs2_info_scan_inode_alloc(struct ocfs2_super *osb,
> if (inode_alloc)
> inode_lock(inode_alloc);
>
> - if (o2info_coherent(&fi->ifi_req)) {
> + if (inode_alloc && o2info_coherent(&fi->ifi_req)) {
> status = ocfs2_inode_lock(inode_alloc, &bh, 0);
> if (status < 0) {
> mlog_errno(status);
>