memory leak in udf_process_sequence

memory leak in udf_process_sequence

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    325d0eab Merge branch 'akpm' (patches from Andrew)
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13ec44d3900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a1f3c5052e8097e9
dashboard link: https://syzkaller.appspot.com/bug?extid=128f4dd6e796c98b3760
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=101a0e9b900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17ae18d3900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+128f4dd6e796c98b3760@syzkaller.appspotmail.com

BUG: memory leak
unreferenced object 0xffff88811a1d0a00 (size 512):
  comm "syz-executor299", pid 6519, jiffies 4294943224 (age 15.090s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<000000009ea2686e>] kmalloc include/linux/slab.h:554 [inline]
    [<000000009ea2686e>] kmalloc_array include/linux/slab.h:593 [inline]
    [<000000009ea2686e>] kcalloc include/linux/slab.h:605 [inline]
    [<000000009ea2686e>] udf_process_sequence+0x7e/0x1080 fs/udf/super.c:1676
    [<00000000d9f60715>] udf_load_sequence fs/udf/super.c:1795 [inline]
    [<00000000d9f60715>] udf_check_anchor_block+0xdc/0x1a0 fs/udf/super.c:1835
    [<0000000067395456>] udf_scan_anchors+0x9e/0x240 fs/udf/super.c:1868
    [<00000000966a1b37>] udf_find_anchor fs/udf/super.c:1925 [inline]
    [<00000000966a1b37>] udf_load_vrs+0x1be/0x3b0 fs/udf/super.c:1990
    [<0000000004bba192>] udf_fill_super+0x286/0x7a5 fs/udf/super.c:2183
    [<00000000d48efb9b>] mount_bdev+0x1d3/0x210 fs/super.c:1417
    [<00000000280e173c>] legacy_get_tree+0x26/0x70 fs/fs_context.c:592
    [<0000000059fde270>] vfs_get_tree+0x28/0xe0 fs/super.c:1547
    [<00000000904c79e7>] do_new_mount fs/namespace.c:2875 [inline]
    [<00000000904c79e7>] path_mount+0x90e/0xda0 fs/namespace.c:3192
    [<000000008e0f8bcd>] do_mount fs/namespace.c:3205 [inline]
    [<000000008e0f8bcd>] __do_sys_mount fs/namespace.c:3413 [inline]
    [<000000008e0f8bcd>] __se_sys_mount fs/namespace.c:3390 [inline]
    [<000000008e0f8bcd>] __x64_sys_mount+0x140/0x190 fs/namespace.c:3390
    [<00000000e981acac>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<000000006322386a>] entry_SYSCALL_64_after_hwframe+0x44/0xa9



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[Linux-kernel-mentees] [PATCH] udf: Fix memory leak in udf_process_sequence()

[Peilin Ye]

udf_process_sequence() is leaking memory. Free `data.part_descs_loc`
before returning.

Cc: stable@vger.kernel.org
Fixes: 7b78fd02fb19 ("udf: Fix handling of Partition Descriptors")
Reported-and-tested-by: syzbot+128f4dd6e796c98b3760@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=c5ec4e6f5d818f3c4afd4d59342468eec08a38da
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
---
 fs/udf/super.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 1c42f544096d..b0d862ab3024 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -1698,7 +1698,8 @@ static noinline int udf_process_sequence(
 					"Pointers (max %u supported)\n",
 					UDF_MAX_TD_NESTING);
 				brelse(bh);
-				return -EIO;
+				ret = -EIO;
+				goto out;
 			}
 
 			vdp = (struct volDescPtr *)bh->b_data;
@@ -1718,7 +1719,8 @@ static noinline int udf_process_sequence(
 			curr = get_volume_descriptor_record(ident, bh, &data);
 			if (IS_ERR(curr)) {
 				brelse(bh);
-				return PTR_ERR(curr);
+				ret = PTR_ERR(curr);
+				goto out;
 			}
 			/* Descriptor we don't care about? */
 			if (!curr)
@@ -1740,28 +1742,32 @@ static noinline int udf_process_sequence(
 	 */
 	if (!data.vds[VDS_POS_PRIMARY_VOL_DESC].block) {
 		udf_err(sb, "Primary Volume Descriptor not found!\n");
-		return -EAGAIN;
+		ret = -EAGAIN;
+		goto out;
 	}
 	ret = udf_load_pvoldesc(sb, data.vds[VDS_POS_PRIMARY_VOL_DESC].block);
 	if (ret < 0)
-		return ret;
+		goto out;
 
 	if (data.vds[VDS_POS_LOGICAL_VOL_DESC].block) {
 		ret = udf_load_logicalvol(sb,
 				data.vds[VDS_POS_LOGICAL_VOL_DESC].block,
 				fileset);
 		if (ret < 0)
-			return ret;
+			goto out;
 	}
 
 	/* Now handle prevailing Partition Descriptors */
 	for (i = 0; i < data.num_part_descs; i++) {
 		ret = udf_load_partdesc(sb, data.part_descs_loc[i].rec.block);
 		if (ret < 0)
-			return ret;
+			goto out;
 	}
 
-	return 0;
+	ret = 0;
+out:
+	kfree(data.part_descs_loc);
+	return ret;
 }
 
 /*
-- 
2.25.1

Re: [Linux-kernel-mentees] [PATCH] udf: Fix memory leak in udf_process_sequence()

[Jan Kara]

On Tue 22-09-20 11:45:31, Peilin Ye wrote:
> udf_process_sequence() is leaking memory. Free `data.part_descs_loc`
> before returning.
> 
> Cc: stable@vger.kernel.org
> Fixes: 7b78fd02fb19 ("udf: Fix handling of Partition Descriptors")
> Reported-and-tested-by: syzbot+128f4dd6e796c98b3760@syzkaller.appspotmail.com
> Link: https://syzkaller.appspot.com/bug?id=c5ec4e6f5d818f3c4afd4d59342468eec08a38da
> Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>

Thanks for the patch but I've just yesterday written exactly the same patch
and merged it to my tree...

								Honza

> ---
>  fs/udf/super.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/udf/super.c b/fs/udf/super.c
> index 1c42f544096d..b0d862ab3024 100644
> --- a/fs/udf/super.c
> +++ b/fs/udf/super.c
> @@ -1698,7 +1698,8 @@ static noinline int udf_process_sequence(
>  					"Pointers (max %u supported)\n",
>  					UDF_MAX_TD_NESTING);
>  				brelse(bh);
> -				return -EIO;
> +				ret = -EIO;
> +				goto out;
>  			}
>  
>  			vdp = (struct volDescPtr *)bh->b_data;
> @@ -1718,7 +1719,8 @@ static noinline int udf_process_sequence(
>  			curr = get_volume_descriptor_record(ident, bh, &data);
>  			if (IS_ERR(curr)) {
>  				brelse(bh);
> -				return PTR_ERR(curr);
> +				ret = PTR_ERR(curr);
> +				goto out;
>  			}
>  			/* Descriptor we don't care about? */
>  			if (!curr)
> @@ -1740,28 +1742,32 @@ static noinline int udf_process_sequence(
>  	 */
>  	if (!data.vds[VDS_POS_PRIMARY_VOL_DESC].block) {
>  		udf_err(sb, "Primary Volume Descriptor not found!\n");
> -		return -EAGAIN;
> +		ret = -EAGAIN;
> +		goto out;
>  	}
>  	ret = udf_load_pvoldesc(sb, data.vds[VDS_POS_PRIMARY_VOL_DESC].block);
>  	if (ret < 0)
> -		return ret;
> +		goto out;
>  
>  	if (data.vds[VDS_POS_LOGICAL_VOL_DESC].block) {
>  		ret = udf_load_logicalvol(sb,
>  				data.vds[VDS_POS_LOGICAL_VOL_DESC].block,
>  				fileset);
>  		if (ret < 0)
> -			return ret;
> +			goto out;
>  	}
>  
>  	/* Now handle prevailing Partition Descriptors */
>  	for (i = 0; i < data.num_part_descs; i++) {
>  		ret = udf_load_partdesc(sb, data.part_descs_loc[i].rec.block);
>  		if (ret < 0)
> -			return ret;
> +			goto out;
>  	}
>  
> -	return 0;
> +	ret = 0;
> +out:
> +	kfree(data.part_descs_loc);
> +	return ret;
>  }
>  
>  /*
> -- 
> 2.25.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [Linux-kernel-mentees] [PATCH] udf: Fix memory leak in udf_process_sequence()

[Peilin Ye]

Hi,

On Wed, Sep 23, 2020 at 12:04:05PM +0200, Jan Kara wrote:
> On Tue 22-09-20 11:45:31, Peilin Ye wrote:
> > udf_process_sequence() is leaking memory. Free `data.part_descs_loc`
> > before returning.
> > 
> > Cc: stable@vger.kernel.org
> > Fixes: 7b78fd02fb19 ("udf: Fix handling of Partition Descriptors")
> > Reported-and-tested-by: syzbot+128f4dd6e796c98b3760@syzkaller.appspotmail.com
> > Link: https://syzkaller.appspot.com/bug?id=c5ec4e6f5d818f3c4afd4d59342468eec08a38da
> > Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
> 
> Thanks for the patch but I've just yesterday written exactly the same patch
> and merged it to my tree...

Ah, no worries, happy to see the bug gets fixed!

Peilin Ye