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9f1e40193e
aa_vec_unique() null terminates at vec[n - dups] when VEC_FLAG_TERMINATE
is passed. If the components are all distinct no duplicates are dropped,
dups is 0 and the terminator goes to vec[n], so the caller has to provide
room for n + 1 entries.
aa_label_strn_parse() sets up its vector with vec_setup(profile, vec, len,
gfp) and then calls aa_vec_unique(vec, len, VEC_FLAG_TERMINATE), but
vec_setup() does not reserve the terminator entry. Up to LOCAL_VEC_ENTRIES
it uses the local array of LOCAL_VEC_ENTRIES pointers, above that it
allocates exactly len pointers. The terminator therefore lands one entry
past the end of the local array when len is LOCAL_VEC_ENTRIES, and one
entry past the end of the allocation when len is larger.
len comes from the number of "//&" separated components in the label name
and label_count_strn_entries() does not bound it. An unprivileged task
reaches the parse by writing to /proc/self/attr/apparmor/current or through
lsm_set_self_attr(2), both of which go through do_setattr(), and the name
is parsed before the change_profile permission is checked.
The query_label() path behind the securityfs .access file, which is
mode 0666, performs no permission check at all. Every component has to
resolve to a loaded profile, so a system with policy loaded is required.
The other two VEC_FLAG_TERMINATE users work on a label vec that
aa_label_alloc() has already sized with "+ 1 for null terminator entry on
vec". Reserve the same entry in vec_setup() and DEFINE_VEC(). Passing
len + 1 from the caller instead would move len == LOCAL_VEC_ENTRIES out of
the local array and into kzalloc().
Fixes:
|
||
|---|---|---|
| .. | ||
| include | ||
| .gitignore | ||
| .kunitconfig | ||
| af_unix.c | ||
| apparmorfs.c | ||
| audit.c | ||
| capability.c | ||
| crypto.c | ||
| domain.c | ||
| file.c | ||
| ipc.c | ||
| Kconfig | ||
| label.c | ||
| lib.c | ||
| lsm.c | ||
| Makefile | ||
| match.c | ||
| mount.c | ||
| net.c | ||
| nulldfa.in | ||
| path.c | ||
| policy_compat.c | ||
| policy_ns.c | ||
| policy_unpack_test.c | ||
| policy_unpack.c | ||
| policy.c | ||
| procattr.c | ||
| resource.c | ||
| secid.c | ||
| stacksplitdfa.in | ||
| task.c | ||