[PATCH] squashfs: Fix ambiguity in get_comp_opts() return value handling

From: Ingyu Jang
Date: Thu Jan 16 2025 - 14:15:34 EST


The return value of the function get_comp_opts() is
checked using IS_ERR().
However, it can return NULL when squashfs_comp_opts() returns NULL,
causing ambiguity in its return value.
This makes it difficult for the caller to clearly determine whether the
function succeeded or an error occurred.
Additionally, it may cause a NULL pointer dereference.

To address this issue, get_comp_opts() has been modified to always
return an appropriate error code wrapped with ERR_PTR() in case of
failure.
With this change, the caller can reliably distinguish between success
and error cases using IS_ERR().

Signed-off-by: Ingyu Jang <ingyujang25@xxxxxxxxx>
---
fs/squashfs/decompressor.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c
index a676084be27e..2988f2d4220c 100644
--- a/fs/squashfs/decompressor.c
+++ b/fs/squashfs/decompressor.c
@@ -117,6 +117,8 @@ static void *get_comp_opts(struct super_block *sb, unsigned short flags)
}

comp_opts = squashfs_comp_opts(msblk, buffer, length);
+ if (!comp_opts)
+ comp_opts = ERR_PTR(-EINVAL);

out:
kfree(actor);
--
2.34.1