[PATCH] ext4: avoid BUG_ON() in ext4_get_inline_entry()

[Vineet Agarwal <agarwal.vineet2006@gmail.com>]

Corrupted inline directory metadata can cause offset to exceed
the inline data size through rec_len processing in
empty_inline_dir().

This triggers BUG_ON() in ext4_get_inline_entry(), causing a
kernel panic before ext4_check_dir_entry() can handle the
corruption gracefully.

Replace BUG_ON() with a NULL return and handle the invalid
offset in the caller by emitting a warning and exiting safely.

This prevents a kernel panic from corrupted inline directory
metadata.

Signed-off-by: Vineet Agarwal <agarwal.vineet2006@gmail.com>
---
 fs/ext4/inline.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 8045e4ff270c..bca9936ed6d0 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1718,7 +1718,8 @@ ext4_get_inline_entry(struct inode *inode,
 {
 	void *inline_pos;
 
-	BUG_ON(offset > ext4_get_inline_size(inode));
+	if (offset > ext4_get_inline_size(inode))
+		return NULL;
 
 	if (offset < EXT4_MIN_INLINE_DATA_SIZE) {
 		inline_pos = (void *)ext4_raw_inode(iloc)->i_block;
@@ -1773,6 +1774,12 @@ bool empty_inline_dir(struct inode *dir, int *has_inline_data)
 	while (offset < inline_len) {
 		de = ext4_get_inline_entry(dir, &iloc, offset,
 					   &inline_pos, &inline_size);
+		if (!de) {
+			ext4_warning(dir->i_sb,
+				     "bad inline directory (dir #%llu) - invalid offset",
+				     dir->i_ino);
+			goto out;
+		}
 		if (ext4_check_dir_entry(dir, NULL, de,
 					 iloc.bh, inline_pos,
 					 inline_size, offset)) {
-- 
2.54.0