From: Hyunwoo Kim <imv4bel@gmail.com> mainline inclusion from mainline-v7.3-rc1 commit 9f1e40193eef7f047e6b77cfb4b4cafdecd7a123 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18781 CVE: CVE-2026-89761 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- 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: f1bd904175e8 ("apparmor: add the base fns() for domain labels") Cc: stable@vger.kernel.org Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Conflicts: security/apparmor/include/label.h [Commit 9f1e40193eef uses kzalloc_objs() for the terminator-sized allocation; that helper does not exist in this tree, so use the equivalent kcalloc().] Signed-off-by: Yi Yang <yiyang13@huawei.com> --- security/apparmor/include/label.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/security/apparmor/include/label.h b/security/apparmor/include/label.h index 55986388dfae..ab223efadd83 100644 --- a/security/apparmor/include/label.h +++ b/security/apparmor/include/label.h @@ -22,7 +22,7 @@ struct aa_ns; #define LOCAL_VEC_ENTRIES 8 #define DEFINE_VEC(T, V) \ - struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES]; \ + struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES + 1]; \ struct aa_ ## T **(V) #define vec_setup(T, V, N, GFP) \ @@ -30,10 +30,10 @@ struct aa_ns; if ((N) <= LOCAL_VEC_ENTRIES) { \ typeof(N) i; \ (V) = (_ ## V ## _localtmp); \ - for (i = 0; i < (N); i++) \ + for (i = 0; i <= (N); i++) \ (V)[i] = NULL; \ } else \ - (V) = kzalloc(sizeof(struct aa_ ## T *) * (N), (GFP)); \ + (V) = kcalloc((N) + 1, sizeof(struct aa_ ## T *), (GFP));\ (V) ? 0 : -ENOMEM; \ }) -- 2.25.1