From: Łukasz Stelmach <l.stelmach@samsung.com>
Date: Fri, 9 Aug 2024 12:53:37 +0000 (+0200)
Subject: kdbus: Translate new u64-based kernel_cap_t to u32-based kdbus_caps
X-Git-Tag: accepted/tizen/unified/20240812.190117^0
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=deeb72f8e7ae8bed01af6719730b282b72843040;p=platform%2Fkernel%2Flinux-tizen-modules-source.git

kdbus: Translate new u64-based kernel_cap_t to u32-based kdbus_caps

Using kernel_cap_t in kdbus_meta_caps changes the alignment of userland
facing structures which breaks userland code trying to parse the structure
sent in kdbus header. Translate kernel_cap_t to u32 similarly to what's
done in capget(2).

Change-Id: I8c21746dca2972cbc0ad48dfea4dba2216c0669c
Ref: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f122a08b197d076ccf136c73fae0146875812a88
Fixes: e59920a ("kdbus: use u64 capability for v6.3 or later version")
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
---

diff --git a/kernel/kdbus/metadata.c b/kernel/kdbus/metadata.c
index 58cd85e..a9e819e 100644
--- a/kernel/kdbus/metadata.c
+++ b/kernel/kdbus/metadata.c
@@ -128,16 +128,18 @@ struct kdbus_meta_conn {
 	char *conn_description;
 };
 
+/* The macros has been missing since 6.3 */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 3, 0)
+#define _KERNEL_CAPABILITY_U32S         2
+#define CAP_LAST_U32_VALID_MASK         (CAP_TO_MASK(CAP_LAST_CAP + 1) -1)
+#endif
+
 /* fixed size equivalent of "kdbus_caps" */
 struct kdbus_meta_caps {
 	u32 last_cap;
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 3, 0)
-	kernel_cap_t cap_sets[4];
-#else
 	struct {
 		u32 caps[_KERNEL_CAPABILITY_U32S];
 	} set[4];
-#endif
 };
 
 /**
@@ -771,25 +773,35 @@ static void kdbus_meta_export_caps(struct kdbus_meta_caps *out,
 
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 3, 0)
 	if (parent) {
-		out->cap_sets[0] = cred->cap_inheritable;
-		out->cap_sets[1] = cred->cap_permitted;
-		out->cap_sets[2] = cred->cap_effective;
-		out->cap_sets[3] = cred->cap_bset;
+		out->set[0].caps[0] = cred->cap_inheritable.val;
+		out->set[0].caps[1] = cred->cap_inheritable.val >> 32;
+		out->set[1].caps[0] = cred->cap_permitted.val;
+		out->set[1].caps[1] = cred->cap_permitted.val >> 32;
+		out->set[2].caps[0] = cred->cap_effective.val;
+		out->set[2].caps[1] = cred->cap_effective.val >> 32;
+		out->set[3].caps[0] = cred->cap_bset.val;
+		out->set[3].caps[1] = cred->cap_bset.val >> 32;
 	} else if (owner) {
-		out->cap_sets[0] = CAP_EMPTY_SET;
-		out->cap_sets[1] = CAP_FULL_SET;
-		out->cap_sets[2] = CAP_FULL_SET;
-		out->cap_sets[3] = CAP_FULL_SET;
+		out->set[0].caps[0] = CAP_EMPTY_SET.val;
+		out->set[0].caps[1] = CAP_EMPTY_SET.val >> 32;
+		out->set[1].caps[0] = CAP_FULL_SET.val;
+		out->set[1].caps[1] = CAP_FULL_SET.val >> 32;
+		out->set[2].caps[0] = CAP_FULL_SET.val;
+		out->set[2].caps[1] = CAP_FULL_SET.val >> 32;
+		out->set[3].caps[0] = CAP_FULL_SET.val;
+		out->set[3].caps[1] = CAP_FULL_SET.val >> 32;
+
 	} else {
-		out->cap_sets[0] = CAP_EMPTY_SET;
-		out->cap_sets[1] = CAP_EMPTY_SET;
-		out->cap_sets[2] = CAP_EMPTY_SET;
-		out->cap_sets[3] = CAP_EMPTY_SET;
+		out->set[0].caps[0] = CAP_EMPTY_SET.val;
+		out->set[0].caps[1] = CAP_EMPTY_SET.val >> 32;
+		out->set[1].caps[0] = CAP_EMPTY_SET.val;
+		out->set[1].caps[1] = CAP_EMPTY_SET.val >> 32;
+		out->set[2].caps[0] = CAP_EMPTY_SET.val;
+		out->set[2].caps[1] = CAP_EMPTY_SET.val >> 32;
+		out->set[3].caps[0] = CAP_EMPTY_SET.val;
+		out->set[3].caps[1] = CAP_EMPTY_SET.val >> 32;
 	}
 
-	/* clear unused bits */
-	for (i = 0; i < 4; i++)
-		out->cap_sets[i].val &= CAP_VALID_MASK;
 #else
 	CAP_FOR_EACH_U32(i) {
 		if (parent) {
@@ -810,11 +822,11 @@ static void kdbus_meta_export_caps(struct kdbus_meta_caps *out,
 		}
 	}
 
+#endif
 	/* clear unused bits */
 	for (i = 0; i < 4; i++)
 		out->set[i].caps[CAP_TO_INDEX(CAP_LAST_CAP)] &=
 					CAP_LAST_U32_VALID_MASK;
-#endif
 }
 
 /* This is equivalent to from_kuid_munged(), but maps INVALID_UID to itself */