[PATCH] bcachefs: Fix null-ptr-deref in bch2_opt_to_text

From: Edward Adam Davis
Date: Thu Sep 19 2024 - 19:08:30 EST


The mounting option values passed in by syzbot are:
"metadata_checksum=crc64, errors=continue, obj_user={^, subj_user=obj_ur,
approve", which does not meet the "key1=value1,key2=value2,..." requirement
of the bcachefs.

Reported-and-tested-by: syzbot+294f528e56138c357a48@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=294f528e56138c357a48
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
fs/bcachefs/opts.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/fs/bcachefs/opts.c b/fs/bcachefs/opts.c
index e10fc1da71b1..78307e092075 100644
--- a/fs/bcachefs/opts.c
+++ b/fs/bcachefs/opts.c
@@ -472,6 +472,12 @@ int bch2_parse_one_mount_opt(struct bch_fs *c, struct bch_opts *opts,
u64 v;
int ret, id;

+ if (!val) {
+ pr_err("Bad mount option, value is NULL");
+ ret = -BCH_ERR_option_value;
+ goto out;
+ }
+
id = bch2_mount_opt_lookup(name);

/* Check for the form "noopt", negation of a boolean opt: */
--
2.43.0