| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 067/111] apparmor: fix potential label refcnt leak in aa_change_profile | Date | Tue, 26 May 2020 20:53:25 +0200 |
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From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
commit a0b845ffa0d91855532b50fc040aeb2d8338dca4 upstream.
aa_change_profile() invokes aa_get_current_label(), which returns a reference of the current task's label.
According to the comment of aa_get_current_label(), the returned reference must be put with aa_put_label(). However, when the original object pointed by "label" becomes unreachable because aa_change_profile() returns or a new object is assigned to "label", reference count increased by aa_get_current_label() is not decreased, causing a refcnt leak.
Fix this by calling aa_put_label() before aa_change_profile() return and dropping unnecessary aa_get_current_label().
Fixes: 9fcf78cca198 ("apparmor: update domain transitions that are subsets of confinement at nnp") Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com> Signed-off-by: John Johansen <john.johansen@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- security/apparmor/domain.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/security/apparmor/domain.c +++ b/security/apparmor/domain.c @@ -1334,6 +1334,7 @@ int aa_change_profile(const char *fqname ctx->nnp = aa_get_label(label); if (!fqname || !*fqname) { + aa_put_label(label); AA_DEBUG("no profile name"); return -EINVAL; } @@ -1352,8 +1353,6 @@ int aa_change_profile(const char *fqname op = OP_CHANGE_PROFILE; } - label = aa_get_current_label(); - if (*fqname == '&') { stack = true; /* don't have label_parse() do stacking */
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