From 80052a218bdc12511f3d59d6bae3e6e1986fe5f1 Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: Jan 25 2024 17:45:57 +0000
Subject: slbt_ar_parse_primary_armap_sysv_32(): perform strict armap validation.


---

diff --git a/include/slibtool/slibtool.h b/include/slibtool/slibtool.h
index 8b5429a..2cf7099 100644
--- a/include/slibtool/slibtool.h
+++ b/include/slibtool/slibtool.h
@@ -110,6 +110,7 @@ enum slbt_custom_error {
 	SLBT_ERR_AR_MISPLACED_ARMAP_MEMBER,
 	SLBT_ERR_AR_NO_ACTION_SPECIFIED,
 	SLBT_ERR_AR_NO_INPUT_SPECIFIED,
+	SLBT_ERR_AR_INVALID_ARMAP_NUMBER_OF_SYMS,
 	SLBT_ERR_AR_INVALID_ARMAP_SIZE_OF_REFS,
 	SLBT_ERR_AR_INVALID_ARMAP_SIZE_OF_STRS,
 	SLBT_ERR_AR_INVALID_ARMAP_STRING_TABLE,
diff --git a/src/arbits/slbt_archive_meta.c b/src/arbits/slbt_archive_meta.c
index 5b6874f..0bd0ac7 100644
--- a/src/arbits/slbt_archive_meta.c
+++ b/src/arbits/slbt_archive_meta.c
@@ -439,6 +439,9 @@ static int slbt_ar_parse_primary_armap_sysv_32(
 	struct ar_meta_member_info *    memberp;
 	struct ar_meta_armap_common_32 *armapref;
 	uint32_t                        nsyms;
+	uint32_t                        nstrs;
+	const char *                    ch;
+	const char *                    cap;
 	unsigned char *                 uch;
 	unsigned char                   (*mark)[0x04];
 
@@ -455,8 +458,46 @@ static int slbt_ar_parse_primary_armap_sysv_32(
 	nsyms = (uch[0] << 24) + (uch[1] << 16) + (uch[2] << 8) + uch[3];
 	mark += nsyms;
 
+	if (memberp->ar_object_size < (sizeof(*mark) + (nsyms * sizeof(*mark))))
+		return SLBT_CUSTOM_ERROR(
+			dctx,
+			SLBT_ERR_AR_INVALID_ARMAP_NUMBER_OF_SYMS);
+
 	m->symstrs = (const char *)mark;
 
+	cap  = memberp->ar_object_data;
+	cap += memberp->ar_object_size;
+
+	if (cap == m->symstrs)
+		return SLBT_CUSTOM_ERROR(
+			dctx,
+			SLBT_ERR_AR_INVALID_ARMAP_STRING_TABLE);
+
+	if (nsyms && !m->symstrs[0])
+		return SLBT_CUSTOM_ERROR(
+			dctx,
+			SLBT_ERR_AR_INVALID_ARMAP_STRING_TABLE);
+
+	for (ch=&m->symstrs[1],nstrs=0; ch<cap; ch++) {
+		if (!ch[0] && !ch[-1] && (nstrs < nsyms))
+			return SLBT_CUSTOM_ERROR(
+				dctx,
+				SLBT_ERR_AR_INVALID_ARMAP_STRING_TABLE);
+
+		if (!ch[0] && ch[-1])
+			nstrs++;
+	}
+
+	if (nstrs != nsyms)
+		return SLBT_CUSTOM_ERROR(
+			dctx,
+			SLBT_ERR_AR_INVALID_ARMAP_STRING_TABLE);
+
+	if (cap[-1])
+		return SLBT_CUSTOM_ERROR(
+			dctx,
+			SLBT_ERR_AR_INVALID_ARMAP_STRING_TABLE);
+
 	if (!(m->symstrv = calloc(nsyms + 1,sizeof(const char *))))
 		return SLBT_SYSTEM_ERROR(dctx,0);