d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Use address space guard to implement inter-segment gap.

Browse Source 
Rtld checks and use old MAP_ANON/PROT_NONE method of creating gap if
running on old kernel.

Reviewed by:	alc, markj
Tested by:	pho, Qualys
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2017-06-24 17:04:27 +00:00
parent 19bd0d9c85
commit a36deee3d3
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=320318
1 changed files with 4 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
libexec/rtld-elf/map_object.c
View File

@ -41,6 +41,8 @@
static Elf_Ehdr *get_elf_header(int, const char *, const struct stat *);
static int convert_flags(int); /* Elf flags -> mmap flags */
int __getosreldate(void);
/*
* Map a shared object into memory. The "fd" argument is a file descriptor,
* which must be open on the object and positioned at its beginning.
@ -190,7 +192,8 @@ map_object(int fd, const char *path, const struct stat *sb)
base_vlimit = round_page(segs[nsegs]->p_vaddr + segs[nsegs]->p_memsz);
mapsize = base_vlimit - base_vaddr;
base_addr = (caddr_t) base_vaddr;
base_flags = MAP_PRIVATE | MAP_ANON | MAP_NOCORE;
base_flags = __getosreldate() >= P_OSREL_MAP_GUARD ? MAP_GUARD :
MAP_PRIVATE | MAP_ANON | MAP_NOCORE;
if (npagesizes > 1 && round_page(segs[0]->p_filesz) >= pagesizes[1])
base_flags |= MAP_ALIGNED_SUPER;
if (base_vaddr != 0)