In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
apparmor: fix out-of-bounds write when null terminating a label vec<\/p>\n
aa_vec_unique() null terminates at vec[n – dups] when VEC_FLAG_TERMINATE
\nis passed. If the components are all distinct no duplicates are dropped,
\ndups is 0 and the terminator goes to vec[n], so the caller has to provide
\nroom for n + 1 entries.<\/p>\n
aa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len,
\ngfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but
\nvec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES
\nit uses the local array of LOCAL_VEC_ENTRIES pointers, above that it
\nallocates exactly len pointers. The terminator therefore lands one entry
\npast the end of the local array when len is LOCAL_VEC_ENTRIES, and one
\nentry past the end of the allocation when len is larger.<\/p>\n
len comes from the number of “\/\/&” separated components in the label name
\nand label_count_strn_entries() does not bound it. An unprivileged task
\nreaches the parse by writing to \/proc\/self\/attr\/apparmor\/current or through
\nlsm_set_self_attr(2), both of which go through do_setattr(), and the name
\nis parsed before the change_profile permission is checked.
\nThe query_label() path behind the securityfs .access file, which is
\nmode 0666, performs no permission check at all. Every component has to
\nresolve to a loaded profile, so a system with policy loaded is required.<\/p>\n
The other two VEC_FLAG_TERMINATE users work on a label vec that
\naa_label_alloc() has already sized with “+ 1 for null terminator entry on
\nvec”. Reserve the same entry in vec_setup() and DEFINE_VEC(). Passing
\nlen + 1 from the caller instead would move len == LOCAL_VEC_ENTRIES out of
\nthe local array and into kzalloc().<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
apparmor: fix out-of-bounds write when null terminating a label vec<\/p>\n
aa_vec_unique() null terminates at vec[n – dups] when VEC_FLAG<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21683","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21683","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21683"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21683"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21683"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}