6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yichong Chen <redacted>
commit e97bbe1b2bd82ec2ae37ad2e4965b4d3e78bbf7f upstream.
ecryptfs_parse_tag_70_packet() subtracts fixed metadata fields from the
parsed packet body size to derive the encrypted filename size. A
malformed packet with a body smaller than those fixed fields can underflow
that size calculation.
Reject tag 70 packets before the subtraction unless the body contains the
signature, cipher code, and at least one byte of encrypted filename data.
Fixes: 9c79f34f7ee7 ("eCryptfs: Filename Encryption: Tag 70 packets")
Cc: <redacted>
Signed-off-by: Yichong Chen <redacted>
Signed-off-by: Tyler Hicks <code@tyhicks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ecryptfs/keystore.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -937,6 +937,12 @@ ecryptfs_parse_tag_70_packet(char **file
"rc = [%d]\n", __func__, rc);
goto out;
}
+ if (s->parsed_tag_70_packet_size < (ECRYPTFS_SIG_SIZE + 2)) {
+ ecryptfs_printk(KERN_WARNING, "Invalid packet size [%zd]\n",
+ s->parsed_tag_70_packet_size);
+ rc = -EINVAL;
+ goto out;
+ }
s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
- ECRYPTFS_SIG_SIZE - 1);
if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)