Author: kib
Date: Sat Jan 8 17:13:43 2011
New Revision: 217154
URL: http://svn.freebsd.org/changeset/base/217154
Log:
Implement __pthread_map_stacks_exec() callback for libc, to change the
stack protection to allow execution for single-threaded processes.
Modified:
head/lib/libc/gen/Symbol.map
head/lib/libc/gen/dlfcn.c
head/lib/libc/gen/elf_utils.c
Modified: head/lib/libc/gen/Symbol.map
==============================================================================
--- head/lib/libc/gen/Symbol.map Sat Jan 8 17:11:49 2011
(r217153)
+++ head/lib/libc/gen/Symbol.map Sat Jan 8 17:13:43 2011
(r217154)
@@ -453,6 +453,7 @@ FBSDprivate_1.0 {
_rtld_atfork_pre;
_rtld_atfork_post;
_rtld_error; /* for private use */
+ _rtld_get_stack_prot;
_rtld_thread_init; /* for private use */
__elf_phdr_match_addr;
_err;
@@ -499,4 +500,5 @@ FBSDprivate_1.0 {
_libc_sem_getvalue_compat;
__elf_aux_vector;
+ __pthread_map_stacks_exec;
};
Modified: head/lib/libc/gen/dlfcn.c
==============================================================================
--- head/lib/libc/gen/dlfcn.c Sat Jan 8 17:11:49 2011 (r217153)
+++ head/lib/libc/gen/dlfcn.c Sat Jan 8 17:13:43 2011 (r217154)
@@ -30,6 +30,7 @@ __FBSDID("$FreeBSD$");
/*
* Linkage to services provided by the dynamic linker.
*/
+#include <sys/mman.h>
#include <dlfcn.h>
#include <link.h>
#include <stddef.h>
@@ -165,3 +166,12 @@ _rtld_addr_phdr(const void *addr, struct
return (0);
}
+
+#pragma weak _rtld_get_stack_prot
+int
+_rtld_get_stack_prot(void)
+{
+
+ return (PROT_EXEC | PROT_READ | PROT_WRITE);
+}
+
Modified: head/lib/libc/gen/elf_utils.c
==============================================================================
--- head/lib/libc/gen/elf_utils.c Sat Jan 8 17:11:49 2011
(r217153)
+++ head/lib/libc/gen/elf_utils.c Sat Jan 8 17:13:43 2011
(r217154)
@@ -26,7 +26,12 @@
* $FreeBSD$
*/
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <sys/resource.h>
+#include <sys/sysctl.h>
#include <link.h>
+#include <stddef.h>
int
__elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
@@ -45,3 +50,25 @@ __elf_phdr_match_addr(struct dl_phdr_inf
}
return (i != phdr_info->dlpi_phnum);
}
+
+#pragma weak __pthread_map_stacks_exec
+void
+__pthread_map_stacks_exec(void)
+{
+ int mib[2];
+ struct rlimit rlim;
+ u_long usrstack;
+ size_t len;
+
+ mib[0] = CTL_KERN;
+ mib[1] = KERN_USRSTACK;
+ len = sizeof(usrstack);
+ if (sysctl(mib, sizeof(mib) / sizeof(mib[0]), &usrstack, &len, NULL, 0)
+ == -1)
+ return;
+ if (getrlimit(RLIMIT_STACK, &rlim) == -1)
+ return;
+ mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur),
+ rlim.rlim_cur, _rtld_get_stack_prot());
+}
+
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