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* [PATCH] f2fs: check memory boundary by insane namelen
@ 2018-11-15  7:50 Jaegeuk Kim
  2018-11-17  2:27 ` [f2fs-dev] " Chao Yu
  2018-11-23 12:11 ` Sheng Yong
  0 siblings, 2 replies; 5+ messages in thread
From: Jaegeuk Kim @ 2018-11-15  7:50 UTC (permalink / raw)
  To: linux-kernel, linux-f2fs-devel; +Cc: Jaegeuk Kim

If namelen is corrupted to have very long value, fill_dentries can copy
wrong memory area.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/dir.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index bacc667950b6..c0c845da12fa 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -808,6 +808,17 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
 		de_name.name = d->filename[bit_pos];
 		de_name.len = le16_to_cpu(de->name_len);
 
+		/* check memory boundary before moving forward */
+		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
+		if (unlikely(bit_pos > d->max)) {
+			f2fs_msg(sbi->sb, KERN_WARNING,
+				"%s: corrupted namelen=%d, run fsck to fix.",
+				__func__, le16_to_cpu(de->name_len));
+			set_sbi_flag(sbi, SBI_NEED_FSCK);
+			err = -EINVAL;
+			goto out;
+		}
+
 		if (f2fs_encrypted_inode(d->inode)) {
 			int save_len = fstr->len;
 
@@ -830,7 +841,6 @@ int f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
 		if (readdir_ra)
 			f2fs_ra_node_page(sbi, le32_to_cpu(de->ino));
 
-		bit_pos += GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
 		ctx->pos = start_pos + bit_pos;
 	}
 out:
-- 
2.19.0.605.g01d371f741-goog


^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2018-11-26 23:25 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-11-15  7:50 [PATCH] f2fs: check memory boundary by insane namelen Jaegeuk Kim
2018-11-17  2:27 ` [f2fs-dev] " Chao Yu
2018-11-23 12:11 ` Sheng Yong
2018-11-24  9:59   ` Chao Yu
2018-11-26 23:25   ` Jaegeuk Kim

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