This is a note to let you know that I've just added the patch titled
udf: Fix NULL pointer dereference in udf_symlink function
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
udf-fix-null-pointer-dereference-in-udf_symlink-func.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 49ece004abf4183f7f5a2dcf5ccef274086e55d6
Author: Arturo Giusti <koredump@xxxxxxxxxxxxxx>
Date: Tue May 18 12:34:57 2021 +0200
udf: Fix NULL pointer dereference in udf_symlink function
[ Upstream commit fa236c2b2d4436d9f19ee4e5d5924e90ffd7bb43 ]
In function udf_symlink, epos.bh is assigned with the value returned
by udf_tgetblk. The function udf_tgetblk is defined in udf/misc.c
and returns the value of sb_getblk function that could be NULL.
Then, epos.bh is used without any check, causing a possible
NULL pointer dereference when sb_getblk fails.
This fix adds a check to validate the value of epos.bh.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=213083
Signed-off-by: Arturo Giusti <koredump@xxxxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 77b6d89b9bcd..3c3d3b20889c 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -933,6 +933,10 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
iinfo->i_location.partitionReferenceNum,
0);
epos.bh = udf_tgetblk(sb, block);
+ if (unlikely(!epos.bh)) {
+ err = -ENOMEM;
+ goto out_no_entry;
+ }
lock_buffer(epos.bh);
memset(epos.bh->b_data, 0x00, bsize);
set_buffer_uptodate(epos.bh);
