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ext4: check for NUL characters in extended attribute's name

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Extended attribute names are defined to be NUL-terminated, so the name
must not contain a NUL character.  This is important because there are
places when remove extended attribute, the code uses strlen to
determine the length of the entry.  That should probably be fixed at
some point, but code is currently really messy, so the simplest fix
for now is to simply validate that the extended attributes are sane.

https://bugzilla.kernel.org/show_bug.cgi?id=200401

Reported-by: Wen Xu <wen.xu@gatech.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
This commit is contained in:
Theodore Ts'o 2018-08-01 12:36:52 -04:00
parent 5ef2a69993
commit 7d95178c77
1 changed files with 2 additions and 0 deletions
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2
fs/ext4/xattr.c
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@ -190,6 +190,8 @@ ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end,
struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e);
if ((void *)next >= end)
return -EFSCORRUPTED;
if (strnlen(e->e_name, e->e_name_len) != e->e_name_len)
return -EFSCORRUPTED;
e = next;
}