svn commit: r365433 - head/sys/kern

[Konstantin Belousov]

Author: kib
Date: Mon Sep  7 21:37:16 2020
New Revision: 365433
URL: https://svnweb.freebsd.org/changeset/base/365433

Log:
  imgact_elf.c: unify check for phdr fitting into the first page.
  
  Similar to the userspace rtld check.
  
  Reviewed by:	dim, emaste (previous versions)
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week
  Differential revision:	https://reviews.freebsd.org/D26339

Modified:
  head/sys/kern/imgact_elf.c

Modified: head/sys/kern/imgact_elf.c
==============================================================================
--- head/sys/kern/imgact_elf.c	Mon Sep  7 21:32:27 2020	(r365432)
+++ head/sys/kern/imgact_elf.c	Mon Sep  7 21:37:16 2020	(r365433)
@@ -448,6 +448,13 @@ __elfN(get_brandinfo)(struct image_params *imgp, const
 	return (NULL);
 }
 
+static bool
+__elfN(phdr_in_zero_page)(const Elf_Ehdr *hdr)
+{
+	return (hdr->e_phoff <= PAGE_SIZE &&
+	    (u_int)hdr->e_phentsize * hdr->e_phnum <= PAGE_SIZE - hdr->e_phoff);
+}
+
 static int
 __elfN(check_header)(const Elf_Ehdr *hdr)
 {
@@ -811,8 +818,7 @@ __elfN(load_file)(struct proc *p, const char *file, u_
 	}
 
 	/* Only support headers that fit within first page for now      */
-	if ((hdr->e_phoff > PAGE_SIZE) ||
-	    (u_int)hdr->e_phentsize * hdr->e_phnum > PAGE_SIZE - hdr->e_phoff) {
+	if (!__elfN(phdr_in_zero_page)(hdr)) {
 		error = ENOEXEC;
 		goto fail;
 	}
@@ -1088,9 +1094,7 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *i
 	 * detected an ELF file.
 	 */
 
-	if ((hdr->e_phoff > PAGE_SIZE) ||
-	    (u_int)hdr->e_phentsize * hdr->e_phnum > PAGE_SIZE - hdr->e_phoff) {
-		/* Only support headers in first page for now */
+	if (!__elfN(phdr_in_zero_page)(hdr)) {
 		uprintf("Program headers not in the first page\n");
 		return (ENOEXEC);
 	}