From 948d0e24f33c3b411b5ec1e320acec889e6781b8 Mon Sep 17 00:00:00 2001
From: Vincent Mihalkovic <vmihalko@redhat.com>
Date: Mon, 6 Feb 2023 15:04:33 +0100
Subject: [PATCH] Improve detection of static-pie binaries, and don't call them
 "dynamically linked", but call them "static-pie" linked.

363d7fcf703ad3ebf37b45693b2c9e43eb8b4176
---
 src/readelf.c | 35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/src/readelf.c b/src/readelf.c
index 9c75c0a..0011659 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -1040,7 +1040,7 @@ do_auxv_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type,
 
 private size_t
 dodynamic(struct magic_set *ms, void *vbuf, size_t offset, size_t size,
-    int clazz, int swap)
+    int clazz, int swap, int *pie, size_t *need)
 {
 	Elf32_Dyn dh32;
 	Elf64_Dyn dh64;
@@ -1058,11 +1058,15 @@ dodynamic(struct magic_set *ms, void *vbuf, size_t offset, size_t size,
 
 	switch (xdh_tag) {
 	case DT_FLAGS_1:
+                *pie = 1;
 		if (xdh_val & DF_1_PIE)
 			ms->mode |= 0111;
 		else
 			ms->mode &= ~0111;
 		break;
+        case DT_NEEDED:
+                (*need)++;
+                break;
 	default:
 		break;
 	}
@@ -1529,9 +1533,10 @@ doshn(struct magic_set *ms, int clazz, int swap, int fd, off_t off, int num,
 }
 
 /*
- * Look through the program headers of an executable image, searching
- * for a PT_INTERP section; if one is found, it's dynamically linked,
- * otherwise it's statically linked.
+ * Look through the program headers of an executable image, to determine
+ * if it is statically or dynamically linked. If it has a dynamic section,
+ * it is pie, and does not have an interpreter or needed libraries, we
+ * call it static pie.
  */
 private int
 dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
@@ -1540,12 +1545,13 @@ dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
 {
 	Elf32_Phdr ph32;
 	Elf64_Phdr ph64;
-	const char *linking_style = "statically";
+	const char *linking_style;
 	unsigned char nbuf[BUFSIZ];
 	char ibuf[BUFSIZ];
 	char interp[BUFSIZ];
 	ssize_t bufsize;
-	size_t offset, align, len;
+	size_t offset, align, len, need = 0;
+        int pie = 0, dynamic = 0;
 	
 	if (size != xph_sizeof) {
 		if (file_printf(ms, ", corrupted program header size") == -1)
@@ -1569,7 +1575,6 @@ dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
 		/* Things we can determine before we seek */
 		switch (xph_type) {
 		case PT_DYNAMIC:
-			linking_style = "dynamically";
 			doread = 1;
 			break;
 		case PT_NOTE:
@@ -1610,6 +1615,7 @@ dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
 		/* Things we can determine when we seek */
 		switch (xph_type) {
 		case PT_DYNAMIC:
+			dynamic = 1;
 			offset = 0;
                         // Let DF_1 determine if we are PIE or not.
                         ms->mode &= ~0111;
@@ -1617,7 +1623,8 @@ dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
 				if (offset >= (size_t)bufsize)
 					break;
 				offset = dodynamic(ms, nbuf, offset,
-				    CAST(size_t, bufsize), clazz, swap);
+				    CAST(size_t, bufsize), clazz, swap,
+				    &pie, &need);
 				if (offset == 0)
 					break;
 			}
@@ -1626,6 +1633,7 @@ dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
 			break;
 
 		case PT_INTERP:
+                        need++;
                         if (ms->flags & MAGIC_MIME)
                                 continue;
 			if (bufsize && nbuf[0]) {
@@ -1660,8 +1668,15 @@ dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off,
 	}
 	if (ms->flags & MAGIC_MIME)
 		return 0;
-	if (file_printf(ms, ", %s linked", linking_style)
-	    == -1)
+	if (dynamic) {
+		if (pie && need == 0)
+			linking_style = "static-pie";
+		else
+			linking_style = "dynamically";
+	} else {
+		linking_style = "statically";
+	}
+	if (file_printf(ms, ", %s linked", linking_style) == -1)
 		return -1;
 	if (interp[0])
 		if (file_printf(ms, ", interpreter %s",
-- 
2.39.1