[PATCH 5.15 215/935] udf: Fix i_lenExtents truncation on 32-bit kernels

From
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date
2026-09-12 18:21:48
Also in
linux-patches
Reply to
Greg Kroah-Hartman, 2026-09-12
5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Zhan Xusheng <redacted>

commit a5a5ed23b1340ff0f32a14a7ca8585f7c4e9b2e2 upstream.

In udf_do_extend_file() the total extent length is rounded up to a block
boundary with:

	iinfo->i_lenExtents = (iinfo->i_lenExtents + sb->s_blocksize - 1) &
			      ~(sb->s_blocksize - 1);

i_lenExtents is a __u64, but sb->s_blocksize is unsigned long.  On 32-bit
kernels unsigned long is 32-bit, so ~(sb->s_blocksize - 1) is a 32-bit
value (e.g. 0xfffff800 for a 2 KiB block) that is zero-extended in the AND,
clearing the upper 32 bits of i_lenExtents.  For UDF files whose total
extent length exceeds 4 GiB this truncates i_lenExtents when the file is
extended, corrupting the tracked extent length.

Cast the block size to 64-bit before forming the mask.  64-bit kernels are
unaffected.

Fixes: 48d6d8ff7dca ("udf: cache struct udf_inode_info")
Cc: <redacted>
Signed-off-by: Zhan Xusheng <redacted>
Link: https://patch.msgid.link/20260722082425.213311-1-zhanxusheng@xiaomi.com (local)
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/udf/inode.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -420,7 +420,7 @@ static int udf_do_extend_file(struct ino
 			  sb->s_blocksize - 1) & ~(sb->s_blocksize - 1));
 		iinfo->i_lenExtents =
 			(iinfo->i_lenExtents + sb->s_blocksize - 1) &
-			~(sb->s_blocksize - 1);
+			~((u64)sb->s_blocksize - 1);
 	}
 
 	/* Can we merge with the previous extent? */

Thread (970 messages) 970 messages, 11 authors, last reply 2026-09-20
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