From: Stephen Smalley sds@tycho.nsa.gov
commit 1a37079c236d55fb31ebbf4b59945dab8ec8764c upstream.
This reverts commit e46e01eebbbc ("selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link"). The correct fix is to instead fall back to ref-walk if audit is required irrespective of the specific audit data type. This is done in the next commit.
Fixes: e46e01eebbbc ("selinux: stop passing MAY_NOT_BLOCK to the AVC upon follow_link") Reported-by: Will Deacon will@kernel.org Signed-off-by: Stephen Smalley sds@tycho.nsa.gov Signed-off-by: Paul Moore paul@paul-moore.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- security/selinux/avc.c | 24 ++++++++++++++++++++++-- security/selinux/hooks.c | 5 +++-- security/selinux/include/avc.h | 5 +++++ 3 files changed, 30 insertions(+), 4 deletions(-)
--- a/security/selinux/avc.c +++ b/security/selinux/avc.c @@ -862,8 +862,9 @@ static int avc_update_node(struct selinu * permissive mode that only appear when in enforcing mode. * * See the corresponding handling in slow_avc_audit(), and the - * logic in selinux_inode_permission for the MAY_NOT_BLOCK flag, - * which is transliterated into AVC_NONBLOCKING. + * logic in selinux_inode_follow_link and selinux_inode_permission + * for the VFS MAY_NOT_BLOCK flag, which is transliterated into + * AVC_NONBLOCKING for avc_has_perm_noaudit(). */ if (flags & AVC_NONBLOCKING) return 0; @@ -1203,6 +1204,25 @@ int avc_has_perm(struct selinux_state *s if (rc2) return rc2; return rc; +} + +int avc_has_perm_flags(struct selinux_state *state, + u32 ssid, u32 tsid, u16 tclass, u32 requested, + struct common_audit_data *auditdata, + int flags) +{ + struct av_decision avd; + int rc, rc2; + + rc = avc_has_perm_noaudit(state, ssid, tsid, tclass, requested, + (flags & MAY_NOT_BLOCK) ? AVC_NONBLOCKING : 0, + &avd); + + rc2 = avc_audit(state, ssid, tsid, tclass, requested, &avd, rc, + auditdata, flags); + if (rc2) + return rc2; + return rc; }
u32 avc_policy_seqno(struct selinux_state *state) --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3008,8 +3008,9 @@ static int selinux_inode_follow_link(str if (IS_ERR(isec)) return PTR_ERR(isec);
- return avc_has_perm(&selinux_state, - sid, isec->sid, isec->sclass, FILE__READ, &ad); + return avc_has_perm_flags(&selinux_state, + sid, isec->sid, isec->sclass, FILE__READ, &ad, + rcu ? MAY_NOT_BLOCK : 0); }
static noinline int audit_inode_permission(struct inode *inode, --- a/security/selinux/include/avc.h +++ b/security/selinux/include/avc.h @@ -153,6 +153,11 @@ int avc_has_perm(struct selinux_state *s u32 ssid, u32 tsid, u16 tclass, u32 requested, struct common_audit_data *auditdata); +int avc_has_perm_flags(struct selinux_state *state, + u32 ssid, u32 tsid, + u16 tclass, u32 requested, + struct common_audit_data *auditdata, + int flags);
int avc_has_extended_perms(struct selinux_state *state, u32 ssid, u32 tsid, u16 tclass, u32 requested,