2021-07-31 07:58:23

by Tuo Li

Subject: [PATCH] ocfs2: quota_local: fix possible uninitialized-variable access in ocfs2_local_read_info()

A memory block is allocated through kmalloc(), and its return value is
assigned to the pointer oinfo. If the return value of
ocfs2_global_read_info() at line 709 is less than zero,
oinfo->dqi_gqinode may be not initialized. However, it is accessed at
line 775:
iput(oinfo->dqi_gqinode);

To fix this possible uninitialized-variable access, replace kmalloc()
with kzalloc() when allocating memory for oinfo.

Reported-by: TOTE Robot <[email protected]>
Signed-off-by: Tuo Li <[email protected]>
---
fs/ocfs2/quota_local.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
index b1a8b046f4c2..4c1219e08b49 100644
--- a/fs/ocfs2/quota_local.c
+++ b/fs/ocfs2/quota_local.c
@@ -693,7 +693,7 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)

info->dqi_max_spc_limit = 0x7fffffffffffffffLL;
info->dqi_max_ino_limit = 0x7fffffffffffffffLL;
- oinfo = kmalloc(sizeof(struct ocfs2_mem_dqinfo), GFP_NOFS);
+ oinfo = kzalloc(sizeof(struct ocfs2_mem_dqinfo), GFP_NOFS);
if (!oinfo) {
mlog(ML_ERROR, "failed to allocate memory for ocfs2 quota"
" info.");
--
2.25.1

2021-07-31 14:02:43

by Joseph Qi

Subject: Re: [PATCH] ocfs2: quota_local: fix possible uninitialized-variable access in ocfs2_local_read_info()

Thanks for the efforts.
For the issue you mentioned, I'd like just initialized
oinfo->dqi_gqinode as NULL before calling ocfs2_global_read_info().
But it seems still have other issues here such as dqi_gqlock.
We need take care all those initialized in ocfs2_global_read_info()
carefully.

Thanks,
Joseph

On 7/31/21 3:56 PM, Tuo Li wrote:
> A memory block is allocated through kmalloc(), and its return value is
> assigned to the pointer oinfo. If the return value of
> ocfs2_global_read_info() at line 709 is less than zero,
> oinfo->dqi_gqinode may be not initialized. However, it is accessed at
> line 775:
> iput(oinfo->dqi_gqinode);
>
> To fix this possible uninitialized-variable access, replace kmalloc()
> with kzalloc() when allocating memory for oinfo.
>
> Reported-by: TOTE Robot <[email protected]>
> Signed-off-by: Tuo Li <[email protected]>
> ---
> fs/ocfs2/quota_local.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
> index b1a8b046f4c2..4c1219e08b49 100644
> --- a/fs/ocfs2/quota_local.c
> +++ b/fs/ocfs2/quota_local.c
> @@ -693,7 +693,7 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)
>
> info->dqi_max_spc_limit = 0x7fffffffffffffffLL;
> info->dqi_max_ino_limit = 0x7fffffffffffffffLL;
> - oinfo = kmalloc(sizeof(struct ocfs2_mem_dqinfo), GFP_NOFS);
> + oinfo = kzalloc(sizeof(struct ocfs2_mem_dqinfo), GFP_NOFS);
> if (!oinfo) {
> mlog(ML_ERROR, "failed to allocate memory for ocfs2 quota"
> " info.");
>