| Message ID | 20191021160532.7719-1-navid.emamdoost@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] apparmor: Fix use-after-free in aa_audit_rule_init | expand |
On 2019-10-21 11:05:31, Navid Emamdoost wrote: > In the implementation of aa_audit_rule_init(), when aa_label_parse() > fails the allocated memory for rule is released using > aa_audit_rule_free(). But after this release, the return statement > tries to access the label field of the rule which results in > use-after-free. Before releasing the rule, copy errNo and return it > after release. > > Fixes: 52e8c38001d8 ("apparmor: Fix memory leak of rule on error exit path") > Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com> Reviewed-by: Tyler Hicks <tyhicks@canonical.com> Thanks! Tyler > --- > Changes in v3: > -- applied Tyler Hicks recommendation on err initialization. > > security/apparmor/audit.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/security/apparmor/audit.c b/security/apparmor/audit.c > index 5a98661a8b46..597732503815 100644 > --- a/security/apparmor/audit.c > +++ b/security/apparmor/audit.c > @@ -197,8 +197,9 @@ int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule) > rule->label = aa_label_parse(&root_ns->unconfined->label, rulestr, > GFP_KERNEL, true, false); > if (IS_ERR(rule->label)) { > + int err = PTR_ERR(rule->label); > aa_audit_rule_free(rule); > - return PTR_ERR(rule->label); > + return err; > } > > *vrule = rule; > -- > 2.17.1 >
diff --git a/security/apparmor/audit.c b/security/apparmor/audit.c index 5a98661a8b46..597732503815 100644 --- a/security/apparmor/audit.c +++ b/security/apparmor/audit.c @@ -197,8 +197,9 @@ int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule) rule->label = aa_label_parse(&root_ns->unconfined->label, rulestr, GFP_KERNEL, true, false); if (IS_ERR(rule->label)) { + int err = PTR_ERR(rule->label); aa_audit_rule_free(rule); - return PTR_ERR(rule->label); + return err; } *vrule = rule;
In the implementation of aa_audit_rule_init(), when aa_label_parse() fails the allocated memory for rule is released using aa_audit_rule_free(). But after this release, the return statement tries to access the label field of the rule which results in use-after-free. Before releasing the rule, copy errNo and return it after release. Fixes: 52e8c38001d8 ("apparmor: Fix memory leak of rule on error exit path") Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com> --- Changes in v3: -- applied Tyler Hicks recommendation on err initialization. security/apparmor/audit.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)