Author: kib
Date: Sat Jan 8 16:30:59 2011
New Revision: 217152
URL: http://svn.freebsd.org/changeset/base/217152
Log:
In elf image activator, read and apply the stack protection mode from
PT_GNU_STACK program header, if present and enabled. Two new sysctls
are provided, kern.elf32.nxstack and kern.elf64.nxstack, that allow to
enable PT_GNU_STACK for ABIs of specified bitsize, if ABI decided to
support shared page.
Inform rtld about access mode of the stack initial mapping by
AT_STACKPROT aux vector.
At the moment, the default is disabled, waiting for the usermode
support bits.
Modified:
head/sys/kern/imgact_elf.c
Modified: head/sys/kern/imgact_elf.c
==============================================================================
--- head/sys/kern/imgact_elf.c Sat Jan 8 16:13:44 2011 (r217151)
+++ head/sys/kern/imgact_elf.c Sat Jan 8 16:30:59 2011 (r217152)
@@ -115,6 +115,11 @@ static int elf_legacy_coredump = 0;
SYSCTL_INT(_debug, OID_AUTO, __elfN(legacy_coredump), CTLFLAG_RW,
&elf_legacy_coredump, 0, "");
+static int __elfN(nxstack) = 0;
+SYSCTL_INT(__CONCAT(_kern_elf, __ELF_WORD_SIZE), OID_AUTO,
+ nxstack, CTLFLAG_RW, &__elfN(nxstack), 0,
+ __XSTRING(__CONCAT(ELF, __ELF_WORD_SIZE)) ": enable non-executable stack");
+
static Elf_Brandinfo *elf_brand_list[MAX_BRANDS];
#define trunc_page_ps(va, ps) ((va) & ~(ps - 1))
@@ -724,19 +729,24 @@ __CONCAT(exec_, __elfN(imgact))(struct i
n = 0;
baddr = 0;
for (i = 0; i < hdr->e_phnum; i++) {
- if (phdr[i].p_type == PT_LOAD) {
+ switch (phdr[i].p_type) {
+ case PT_LOAD:
if (n == 0)
baddr = phdr[i].p_vaddr;
n++;
- continue;
- }
- if (phdr[i].p_type == PT_INTERP) {
+ break;
+ case PT_INTERP:
/* Path to interpreter */
if (phdr[i].p_filesz > MAXPATHLEN ||
phdr[i].p_offset + phdr[i].p_filesz > PAGE_SIZE)
return (ENOEXEC);
interp = imgp->image_header + phdr[i].p_offset;
- continue;
+ break;
+ case PT_GNU_STACK:
+ if (__elfN(nxstack))
+ imgp->stack_prot =
+ __elfN(trans_prot)(phdr[i].p_flags);
+ break;
}
}
@@ -972,6 +982,8 @@ __elfN(freebsd_fixup)(register_t **stack
AUXARGS_ENTRY(pos, AT_PAGESIZES, imgp->pagesizes);
AUXARGS_ENTRY(pos, AT_PAGESIZESLEN, imgp->pagesizeslen);
}
+ AUXARGS_ENTRY(pos, AT_STACKPROT, imgp->stack_prot != 0 ?
+ imgp->stack_prot : imgp->sysent->sv_stackprot);
AUXARGS_ENTRY(pos, AT_NULL, 0);
free(imgp->auxargs, M_TEMP);
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
