4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 5b841bfab695e3b8ae793172a9ff7990f99cc3e2 ]
Function smack_key_permission() only issues smack requests for the following operations: - KEY_NEED_READ (issues MAY_READ) - KEY_NEED_WRITE (issues MAY_WRITE) - KEY_NEED_LINK (issues MAY_WRITE) - KEY_NEED_SETATTR (issues MAY_WRITE) A blank smack request is issued in all other cases, resulting in smack access being granted if there is any rule defined between subject and object, or denied with -EACCES otherwise.
Request MAY_READ access for KEY_NEED_SEARCH and KEY_NEED_VIEW. Fix the logic in the unlikely case when both MAY_READ and MAY_WRITE are needed. Validate access permission field for valid contents.
Signed-off-by: Zoran Markovic zmarkovic@sierrawireless.com Signed-off-by: Casey Schaufler casey@schaufler-ca.com Cc: Casey Schaufler casey@schaufler-ca.com Cc: James Morris jmorris@namei.org Cc: "Serge E. Hallyn" serge@hallyn.com Signed-off-by: Sasha Levin sashal@kernel.org --- security/smack/smack_lsm.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 81fb4c1631e9..cd720c06b78c 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4333,6 +4333,12 @@ static int smack_key_permission(key_ref_t key_ref, int request = 0; int rc;
+ /* + * Validate requested permissions + */ + if (perm & ~KEY_NEED_ALL) + return -EINVAL; + keyp = key_ref_to_ptr(key_ref); if (keyp == NULL) return -EINVAL; @@ -4356,10 +4362,10 @@ static int smack_key_permission(key_ref_t key_ref, ad.a.u.key_struct.key = keyp->serial; ad.a.u.key_struct.key_desc = keyp->description; #endif - if (perm & KEY_NEED_READ) - request = MAY_READ; + if (perm & (KEY_NEED_READ | KEY_NEED_SEARCH | KEY_NEED_VIEW)) + request |= MAY_READ; if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR)) - request = MAY_WRITE; + request |= MAY_WRITE; rc = smk_access(tkp, keyp->security, request, &ad); rc = smk_bu_note("key access", tkp, keyp->security, request, rc); return rc;