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

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commit 7d95178c77014dbd8dce36ee40bbbc5e6c121ff5 upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Theodore Ts'o 2018-08-01 12:36:52 -04:00 • committed by Greg Kroah-Hartman
parent f4d76c934b
commit ac92782e4e
1 changed files with 2 additions and 0 deletions
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2
fs/ext4/xattr.c
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@ -197,6 +197,8 @@ ext4_xattr_check_names(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;
}