* [PATCH] udf: NULL dereference at udf_symlink() on error
@ 2015-03-23 6:11 Changwoo Min
2015-04-01 10:55 ` Jan Kara
0 siblings, 1 reply; 2+ messages in thread
From: Changwoo Min @ 2015-03-23 6:11 UTC (permalink / raw)
To: jack, linux-kernel
Cc: taesoo, changwoo, sanidhya, blee, csong84, Changwoo Min
There is no check for udf_tgetblk(), which could return NULL, in udf_symlink().
So there is a possibility of returning NULL under heavy memory pressure and
possibility of NULL dereference.
Signed-off-by: Changwoo Min <changwoo.m@gmail.com>
---
fs/udf/namei.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 33b246b..ed2f221 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -902,6 +902,10 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
iinfo->i_location.partitionReferenceNum,
0);
epos.bh = udf_tgetblk(sb, block);
+ if (!epos.bh) {
+ err = -ENOMEM;
+ goto out_no_entry;
+ }
lock_buffer(epos.bh);
memset(epos.bh->b_data, 0x00, bsize);
set_buffer_uptodate(epos.bh);
--
1.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] udf: NULL dereference at udf_symlink() on error
2015-03-23 6:11 [PATCH] udf: NULL dereference at udf_symlink() on error Changwoo Min
@ 2015-04-01 10:55 ` Jan Kara
0 siblings, 0 replies; 2+ messages in thread
From: Jan Kara @ 2015-04-01 10:55 UTC (permalink / raw)
To: Changwoo Min
Cc: jack, linux-kernel, taesoo, changwoo, sanidhya, blee, csong84
On Mon 23-03-15 02:11:49, Changwoo Min wrote:
> There is no check for udf_tgetblk(), which could return NULL, in udf_symlink().
> So there is a possibility of returning NULL under heavy memory pressure and
> possibility of NULL dereference.
>
> Signed-off-by: Changwoo Min <changwoo.m@gmail.com>
> ---
> fs/udf/namei.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/fs/udf/namei.c b/fs/udf/namei.c
> index 33b246b..ed2f221 100644
> --- a/fs/udf/namei.c
> +++ b/fs/udf/namei.c
> @@ -902,6 +902,10 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
> iinfo->i_location.partitionReferenceNum,
> 0);
> epos.bh = udf_tgetblk(sb, block);
> + if (!epos.bh) {
> + err = -ENOMEM;
This should be -EIO as per our discussion at the previous patch.
Otherwise I agree.
Honza
> + goto out_no_entry;
> + }
> lock_buffer(epos.bh);
> memset(epos.bh->b_data, 0x00, bsize);
> set_buffer_uptodate(epos.bh);
> --
> 1.9.1
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 2+ messages in thread
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