c18n: Improve tracing output, introduce struct utrace_c18n

CTSRD-CHERI · May 8, 2024 · 885b0e5 · 885b0e5
1 parent 958c4ac
commit 885b0e5
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Showing 3 changed files with 61 additions and 25 deletions.
diff --git a/lib/libsysdecode/utrace.c b/lib/libsysdecode/utrace.c
@@ -87,6 +87,29 @@ print_utrace_mrs(FILE *fp, void *p)
 	}
 	return (1);
 }
+
+static int
+print_utrace_c18n(FILE *fp, void *p)
+{
+	struct utrace_c18n *ut = p;
+
+	switch (ut->event) {
+	case UTRACE_COMPARTMENT_ENTER:
+		fprintf(fp, "RTLD: c18n: %s -> %s at [%zu] %s (%02hhx)",
+		    ut->caller, ut->callee, ut->symnum, ut->symbol, ut->fsig);
+		break;
+	case UTRACE_COMPARTMENT_LEAVE:
+		fprintf(fp, "RTLD: c18n: %s <- %s at [%zu] %s (%02hhx)",
+		    ut->caller, ut->callee, ut->symnum, ut->symbol, ut->fsig);
+		break;
+	default:
+		return (0);
+	}
+	fprintf(fp, "\nnsp = %#p\nosp = %#p, previous = %#p\n"
+	    "fp = %#p, pc = %#p", ut->sp, ut->osp, ut->previous,
+	    ut->fp, ut->pc);
+	return (1);
+}
 #endif
 
 #ifdef __LP64__
@@ -200,16 +223,6 @@ print_utrace_rtld(FILE *fp, void *p)
 	case UTRACE_RTLD_ERROR:
 		fprintf(fp, "RTLD: error: %s\n", ut->name);
 		break;
-	case UTRACE_COMPARTMENT_ENTER:
-		fprintf(fp,
-		    "RTLD: c18n: enter %s from %s at [%zu] %s (%p)",
-		    ut->callee, ut->caller, ut->mapsize, ut->symbol, ut->handle);
-		break;
-	case UTRACE_COMPARTMENT_LEAVE:
-		fprintf(fp,
-		    "RTLD: c18n: leave %s to %s at [%zu] %s",
-		    ut->callee, ut->caller, ut->mapsize, ut->symbol);
-		break;
 
 	default:
 		return (0);
@@ -279,10 +292,15 @@ sysdecode_utrace(FILE *fp, void *p, size_t len)
 	static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
 #ifdef __CHERI_PURE_CAPABILITY__
 	static const char mrs_utrace_sig[MRS_UTRACE_SIG_SZ] = MRS_UTRACE_SIG;
+	static const char c18n_utrace_sig[C18N_UTRACE_SIG_SZ] = C18N_UTRACE_SIG;
 
 	if (len == sizeof(struct utrace_mrs) && bcmp(p, mrs_utrace_sig,
 	    sizeof(mrs_utrace_sig)) == 0)
 		return (print_utrace_mrs(fp, p));
+
+	if (len == sizeof(struct utrace_c18n) && bcmp(p, c18n_utrace_sig,
+	    sizeof(c18n_utrace_sig)) == 0)
+		return (print_utrace_c18n(fp, p));
 #endif
 
 	if (len == sizeof(struct utrace_rtld) && bcmp(p, rtld_utrace_sig,

diff --git a/libexec/rtld-elf/rtld_c18n.c b/libexec/rtld-elf/rtld_c18n.c
@@ -1136,8 +1136,7 @@ tramp_hook_impl(int event, const struct tramp_header *hdr,
 	const char *sym;
 	const char *callee;
 	const char *caller;
-	struct utrace_rtld ut;
-	static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] = RTLD_UTRACE_SIG;
+	struct utrace_c18n ut;
 
 	if (ld_compartment_utrace != NULL) {
 		if (hdr->symnum == 0)
@@ -1147,10 +1146,15 @@ tramp_hook_impl(int event, const struct tramp_header *hdr,
 		callee = comparts.data[index_to_cid(tf->callee)].name;
 		caller = comparts.data[index_to_cid(tf->caller)].name;
 
-		memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig));
+		memcpy(ut.sig, C18N_UTRACE_SIG, C18N_UTRACE_SIG_SZ);
 		ut.event = event;
-		ut.handle = hdr->target;
-		ut.mapsize = hdr->symnum;
+		ut.symnum = hdr->symnum;
+		ut.fp = tf->fp;
+		ut.pc = tf->pc;
+		ut.sp = tf->sp;
+		ut.osp = tf->osp;
+		ut.previous = tf->previous;
+		memcpy(&ut.fsig, &hdr->sig, sizeof(ut.fsig));
 		strlcpy(ut.symbol, sym, sizeof(ut.symbol));
 		strlcpy(ut.callee, callee, sizeof(ut.callee));
 		strlcpy(ut.caller, caller, sizeof(ut.caller));

diff --git a/libexec/rtld-elf/rtld_utrace.h b/libexec/rtld-elf/rtld_utrace.h
@@ -44,8 +44,6 @@
 #define	UTRACE_DLSYM_START		11
 #define	UTRACE_DLSYM_STOP		12
 #define	UTRACE_RTLD_ERROR		13
-#define	UTRACE_COMPARTMENT_ENTER	14
-#define	UTRACE_COMPARTMENT_LEAVE	15
 
 #define	RTLD_UTRACE_SIG_SZ		4
 #define	RTLD_UTRACE_SIG			"RTLD"
@@ -57,14 +55,30 @@ struct utrace_rtld {
 	void *mapbase;			/* Used for 'parent' and 'init/fini' */
 	size_t mapsize;
 	int refcnt;			/* Used for 'mode' */
-	union {
-		char name[MAXPATHLEN];
-		struct {
-			char symbol[MAXPATHLEN / 2];
-			char callee[MAXPATHLEN / 4];
-			char caller[MAXPATHLEN / 4];
-		};
-	};
+	char name[MAXPATHLEN];
 };
 
+#ifdef __CHERI_PURE_CAPABILITY__
+#define	UTRACE_COMPARTMENT_ENTER	1
+#define	UTRACE_COMPARTMENT_LEAVE	2
+
+#define	C18N_UTRACE_SIG_SZ		4
+#define	C18N_UTRACE_SIG			"C18N"
+
+struct utrace_c18n {
+	char sig[C18N_UTRACE_SIG_SZ];
+	int event;
+	size_t symnum;
+	void *fp;
+	void *pc;
+	void *sp;
+	void *osp;
+	void *previous;
+	uint8_t fsig;
+	char symbol[256];
+	char callee[128];
+	char caller[128];
+};
+#endif
+
 #endif