* [patch] ext4: potential NULL dereference on error
@ 2012-05-13 14:41 Dan Carpenter
2012-05-14 22:25 ` Jan Kara
0 siblings, 1 reply; 6+ messages in thread
From: Dan Carpenter @ 2012-05-13 14:41 UTC (permalink / raw)
To: Theodore Ts'o; +Cc: Andreas Dilger, linux-ext4, kernel-janitors
The ext4_get_group_desc() function returns NULL on error, and
ext4_free_inodes_count() function dereferences it without checking.
There is a check on the next line, but it's too late.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
Static checker fix.
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index a044a9b..1526f33 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -389,7 +389,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_group_t real_ngroups = ext4_get_groups_count(sb);
int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
- unsigned int freei, avefreei, grp_free;
+ unsigned int freei, avefreei;
ext4_fsblk_t freeb, avefreec;
unsigned int ndirs;
int max_dirs, min_inodes;
@@ -399,6 +399,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
struct orlov_stats stats;
int flex_size = ext4_flex_bg_size(sbi);
struct dx_hash_info hinfo;
+ unsigned int grp_free = 0;
ngroups = real_ngroups;
if (flex_size > 1) {
@@ -508,7 +509,8 @@ fallback_retry:
for (i = 0; i < ngroups; i++) {
grp = (parent_group + i) % ngroups;
desc = ext4_get_group_desc(sb, grp, NULL);
- grp_free = ext4_free_inodes_count(sb, desc);
+ if (desc)
+ grp_free = ext4_free_inodes_count(sb, desc);
if (desc && grp_free && grp_free >= avefreei) {
*group = grp;
return 0;
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [patch] ext4: potential NULL dereference on error
2012-05-13 14:41 [patch] ext4: potential NULL dereference on error Dan Carpenter
@ 2012-05-14 22:25 ` Jan Kara
2012-05-15 6:13 ` Dan Carpenter
2012-05-15 8:46 ` [patch v2] " Dan Carpenter
0 siblings, 2 replies; 6+ messages in thread
From: Jan Kara @ 2012-05-14 22:25 UTC (permalink / raw)
To: Dan Carpenter
Cc: Theodore Ts'o, Andreas Dilger, linux-ext4, kernel-janitors
On Sun 13-05-12 17:41:04, Dan Carpenter wrote:
> The ext4_get_group_desc() function returns NULL on error, and
> ext4_free_inodes_count() function dereferences it without checking.
> There is a check on the next line, but it's too late.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> Static checker fix.
>
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index a044a9b..1526f33 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -389,7 +389,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
> struct ext4_sb_info *sbi = EXT4_SB(sb);
> ext4_group_t real_ngroups = ext4_get_groups_count(sb);
> int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
> - unsigned int freei, avefreei, grp_free;
> + unsigned int freei, avefreei;
> ext4_fsblk_t freeb, avefreec;
> unsigned int ndirs;
> int max_dirs, min_inodes;
> @@ -399,6 +399,7 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
> struct orlov_stats stats;
> int flex_size = ext4_flex_bg_size(sbi);
> struct dx_hash_info hinfo;
> + unsigned int grp_free = 0;
>
> ngroups = real_ngroups;
> if (flex_size > 1) {
> @@ -508,7 +509,8 @@ fallback_retry:
> for (i = 0; i < ngroups; i++) {
> grp = (parent_group + i) % ngroups;
> desc = ext4_get_group_desc(sb, grp, NULL);
> - grp_free = ext4_free_inodes_count(sb, desc);
> + if (desc)
> + grp_free = ext4_free_inodes_count(sb, desc);
> if (desc && grp_free && grp_free >= avefreei) {
So you it would be more logical to do:
if (desc) {
grp_free = ext4_free_inodes_count(sb, desc);
if (grp_free && grpfree >= avefreei) {
*group = grp;
return 0;
}
}
Wouldn't it?
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch] ext4: potential NULL dereference on error
2012-05-14 22:25 ` Jan Kara
@ 2012-05-15 6:13 ` Dan Carpenter
2012-05-15 8:46 ` [patch v2] " Dan Carpenter
1 sibling, 0 replies; 6+ messages in thread
From: Dan Carpenter @ 2012-05-15 6:13 UTC (permalink / raw)
To: Jan Kara; +Cc: Theodore Ts'o, Andreas Dilger, linux-ext4, kernel-janitors
On Tue, May 15, 2012 at 12:25:35AM +0200, Jan Kara wrote:
> On Sun 13-05-12 17:41:04, Dan Carpenter wrote:
> > @@ -508,7 +509,8 @@ fallback_retry:
> > for (i = 0; i < ngroups; i++) {
> > grp = (parent_group + i) % ngroups;
> > desc = ext4_get_group_desc(sb, grp, NULL);
> > - grp_free = ext4_free_inodes_count(sb, desc);
> > + if (desc)
> > + grp_free = ext4_free_inodes_count(sb, desc);
> > if (desc && grp_free && grp_free >= avefreei) {
> So you it would be more logical to do:
> if (desc) {
> grp_free = ext4_free_inodes_count(sb, desc);
> if (grp_free && grpfree >= avefreei) {
> *group = grp;
> return 0;
> }
> }
>
> Wouldn't it?
Yeah. You're obviously right. I'll resend.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 6+ messages in thread
* [patch v2] ext4: potential NULL dereference on error
2012-05-14 22:25 ` Jan Kara
2012-05-15 6:13 ` Dan Carpenter
@ 2012-05-15 8:46 ` Dan Carpenter
2012-05-15 10:01 ` Jan Kara
2012-05-28 15:01 ` Ted Ts'o
1 sibling, 2 replies; 6+ messages in thread
From: Dan Carpenter @ 2012-05-15 8:46 UTC (permalink / raw)
To: Theodore Ts'o, Jan Kara; +Cc: Andreas Dilger, linux-ext4, kernel-janitors
The ext4_get_group_desc() function returns NULL on error, and
ext4_free_inodes_count() function dereferences it without checking.
There is a check on the next line, but it's too late.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: cleaned up the style
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index a044a9b..ea32d7e 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -508,10 +508,12 @@ fallback_retry:
for (i = 0; i < ngroups; i++) {
grp = (parent_group + i) % ngroups;
desc = ext4_get_group_desc(sb, grp, NULL);
- grp_free = ext4_free_inodes_count(sb, desc);
- if (desc && grp_free && grp_free >= avefreei) {
- *group = grp;
- return 0;
+ if (desc) {
+ grp_free = ext4_free_inodes_count(sb, desc);
+ if (grp_free && grp_free >= avefreei) {
+ *group = grp;
+ return 0;
+ }
}
}
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [patch v2] ext4: potential NULL dereference on error
2012-05-15 8:46 ` [patch v2] " Dan Carpenter
@ 2012-05-15 10:01 ` Jan Kara
2012-05-28 15:01 ` Ted Ts'o
1 sibling, 0 replies; 6+ messages in thread
From: Jan Kara @ 2012-05-15 10:01 UTC (permalink / raw)
To: Dan Carpenter
Cc: Theodore Ts'o, Jan Kara, Andreas Dilger, linux-ext4,
kernel-janitors
On Tue 15-05-12 11:46:40, Dan Carpenter wrote:
> The ext4_get_group_desc() function returns NULL on error, and
> ext4_free_inodes_count() function dereferences it without checking.
> There is a check on the next line, but it's too late.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Looks good. Thanks! You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> ---
> v2: cleaned up the style
>
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index a044a9b..ea32d7e 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -508,10 +508,12 @@ fallback_retry:
> for (i = 0; i < ngroups; i++) {
> grp = (parent_group + i) % ngroups;
> desc = ext4_get_group_desc(sb, grp, NULL);
> - grp_free = ext4_free_inodes_count(sb, desc);
> - if (desc && grp_free && grp_free >= avefreei) {
> - *group = grp;
> - return 0;
> + if (desc) {
> + grp_free = ext4_free_inodes_count(sb, desc);
> + if (grp_free && grp_free >= avefreei) {
> + *group = grp;
> + return 0;
> + }
> }
> }
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [patch v2] ext4: potential NULL dereference on error
2012-05-15 8:46 ` [patch v2] " Dan Carpenter
2012-05-15 10:01 ` Jan Kara
@ 2012-05-28 15:01 ` Ted Ts'o
1 sibling, 0 replies; 6+ messages in thread
From: Ted Ts'o @ 2012-05-28 15:01 UTC (permalink / raw)
To: Dan Carpenter; +Cc: Jan Kara, Andreas Dilger, linux-ext4, kernel-janitors
On Tue, May 15, 2012 at 11:46:40AM +0300, Dan Carpenter wrote:
> The ext4_get_group_desc() function returns NULL on error, and
> ext4_free_inodes_count() function dereferences it without checking.
> There is a check on the next line, but it's too late.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Thanks, applied.
- Ted
^ permalink raw reply [flat|nested] 6+ messages in thread
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2012-05-13 14:41 [patch] ext4: potential NULL dereference on error Dan Carpenter
2012-05-14 22:25 ` Jan Kara
2012-05-15 6:13 ` Dan Carpenter
2012-05-15 8:46 ` [patch v2] " Dan Carpenter
2012-05-15 10:01 ` Jan Kara
2012-05-28 15:01 ` Ted Ts'o
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