From: Arturo Giusti koredump@protonmail.com
[ 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@protonmail.com Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Sasha Levin sashal@kernel.org --- fs/udf/namei.c | 4 ++++ 1 file changed, 4 insertions(+)
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);