Author: kib
Date: Sat Sep 28 07:33:08 2019
New Revision: 352833
URL: https://svnweb.freebsd.org/changeset/base/352833
Log:
MFC r352582, r352585:
Make non-ASLR pie base tunable.
Modified:
stable/12/sys/kern/imgact_elf.c
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/sys/kern/imgact_elf.c
==============================================================================
--- stable/12/sys/kern/imgact_elf.c Sat Sep 28 03:33:07 2019
(r352832)
+++ stable/12/sys/kern/imgact_elf.c Sat Sep 28 07:33:08 2019
(r352833)
@@ -136,6 +136,27 @@ SYSCTL_INT(_kern_elf32, OID_AUTO, read_exec, CTLFLAG_R
#endif
#endif
+static u_long __elfN(pie_base) = ET_DYN_LOAD_ADDR;
+static int
+sysctl_pie_base(SYSCTL_HANDLER_ARGS)
+{
+ u_long val;
+ int error;
+
+ val = __elfN(pie_base);
+ error = sysctl_handle_long(oidp, &val, 0, req);
+ if (error != 0 || req->newptr == NULL)
+ return (error);
+ if ((val & PAGE_MASK) != 0)
+ return (EINVAL);
+ __elfN(pie_base) = val;
+ return (0);
+}
+SYSCTL_PROC(__CONCAT(_kern_elf, __ELF_WORD_SIZE), OID_AUTO, pie_base,
+ CTLTYPE_ULONG | CTLFLAG_MPSAFE | CTLFLAG_RW, NULL, 0,
+ sysctl_pie_base, "LU",
+ "PIE load base without randomization");
+
SYSCTL_NODE(__CONCAT(_kern_elf, __ELF_WORD_SIZE), OID_AUTO, aslr, CTLFLAG_RW,
0,
"");
#define ASLR_NODE_OID __CONCAT(__CONCAT(_kern_elf, __ELF_WORD_SIZE),
_aslr)
@@ -1148,13 +1169,13 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *i
if (baddr == 0) {
if ((sv->sv_flags & SV_ASLR) == 0 ||
(fctl0 & NT_FREEBSD_FCTL_ASLR_DISABLE) != 0)
- et_dyn_addr = ET_DYN_LOAD_ADDR;
+ et_dyn_addr = __elfN(pie_base);
else if ((__elfN(pie_aslr_enabled) &&
(imgp->proc->p_flag2 & P2_ASLR_DISABLE) == 0) ||
(imgp->proc->p_flag2 & P2_ASLR_ENABLE) != 0)
et_dyn_addr = ET_DYN_ADDR_RAND;
else
- et_dyn_addr = ET_DYN_LOAD_ADDR;
+ et_dyn_addr = __elfN(pie_base);
}
}
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