svn commit: r314851 - head/sys/kern

[Konstantin Belousov]

Author: kib
Date: Tue Mar  7 13:38:25 2017
New Revision: 314851
URL: https://svnweb.freebsd.org/changeset/base/314851

Log:
  When selecting brand based on old Elf branding, prefer the brand which
  interpreter exactly matches the one requested by the activated image.
  
  This change applies r295277, which did the same for note branding, to
  the old brand selection, with the same reasoning of fixing compat32
  interpreter substitution.
  
  PR:	211837
  Reported by:	kenji at kens.fm
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/kern/imgact_elf.c

Modified: head/sys/kern/imgact_elf.c
==============================================================================
--- head/sys/kern/imgact_elf.c	Tue Mar  7 13:37:35 2017	(r314850)
+++ head/sys/kern/imgact_elf.c	Tue Mar  7 13:38:25 2017	(r314851)
@@ -312,10 +312,23 @@ __elfN(get_brandinfo)(struct image_param
 		    strcmp((const char *)&hdr->e_ident[OLD_EI_BRAND],
 		    bi->compat_3_brand) == 0)) {
 			/* Looks good, but give brand a chance to veto */
-			if (!bi->header_supported || bi->header_supported(imgp))
-				return (bi);
+			if (!bi->header_supported ||
+			    bi->header_supported(imgp)) {
+				/*
+				 * Again, prefer strictly matching
+				 * interpreter path.
+				 */
+				if (strlen(bi->interp_path) + 1 ==
+				    interp_name_len && strncmp(interp,
+				    bi->interp_path, interp_name_len) == 0)
+					return (bi);
+				if (bi_m == NULL)
+					bi_m = bi;
+			}
 		}
 	}
+	if (bi_m != NULL)
+		return (bi_m);
 
 	/* No known brand, see if the header is recognized by any brand */
 	for (i = 0; i < MAX_BRANDS; i++) {