vfs: fs_context: fix up param length parsing in legacy_parse_param

The "PAGE_SIZE - 2 - size" calculation in legacy_parse_param() is an
unsigned type so a large value of "size" results in a high positive
value instead of a negative value as expected.  Fix this by getting rid
of the subtraction.

Signed-off-by: Jamie Hill-Daniel <jamie@hill-daniel.co.uk>
Signed-off-by: William Liu <willsroot@protonmail.com>
Tested-by: Salvatore Bonaccorso <carnil@debian.org>
Tested-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jamie Hill-Daniel 2022-01-18 08:06:04 +01:00 committed by Linus Torvalds
parent 8357f6fb3d
commit 722d94847d

View File

@ -548,7 +548,7 @@ static int legacy_parse_param(struct fs_context *fc, struct fs_parameter *param)
param->key);
}
if (len > PAGE_SIZE - 2 - size)
if (size + len + 2 > PAGE_SIZE)
return invalf(fc, "VFS: Legacy: Cumulative options too large");
if (strchr(param->key, ',') ||
(param->type == fs_value_is_string &&