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-rw-r--r--libexec/rtld-elf/map_object.c29
-rw-r--r--sys/kern/imgact_elf.c42
-rw-r--r--sys/vm/vm.h1
3 files changed, 55 insertions, 17 deletions
diff --git a/libexec/rtld-elf/map_object.c b/libexec/rtld-elf/map_object.c
index a0220ef..7d45662 100644
--- a/libexec/rtld-elf/map_object.c
+++ b/libexec/rtld-elf/map_object.c
@@ -38,7 +38,8 @@
#include "debug.h"
#include "rtld.h"
-static int protflags(int); /* Elf flags -> mmap protection */
+static int convert_prot(int); /* Elf flags -> mmap protection */
+static int convert_flags(int); /* Elf flags -> mmap flags */
/*
* Map a shared object into memory. The "fd" argument is a file descriptor,
@@ -75,6 +76,7 @@ map_object(int fd, const char *path, const struct stat *sb)
Elf_Addr data_vlimit;
caddr_t data_addr;
int data_prot;
+ int data_flags;
Elf_Addr clear_vaddr;
caddr_t clear_addr;
caddr_t clear_page;
@@ -189,8 +191,8 @@ map_object(int fd, const char *path, const struct stat *sb)
mapsize = base_vlimit - base_vaddr;
base_addr = u.hdr.e_type == ET_EXEC ? (caddr_t) base_vaddr : NULL;
- mapbase = mmap(base_addr, mapsize, protflags(segs[0]->p_flags),
- MAP_PRIVATE, fd, base_offset);
+ mapbase = mmap(base_addr, mapsize, convert_prot(segs[0]->p_flags),
+ convert_flags(segs[0]->p_flags), fd, base_offset);
if (mapbase == (caddr_t) -1) {
_rtld_error("%s: mmap of entire address space failed: %s",
path, strerror(errno));
@@ -209,10 +211,11 @@ map_object(int fd, const char *path, const struct stat *sb)
data_vaddr = trunc_page(segs[i]->p_vaddr);
data_vlimit = round_page(segs[i]->p_vaddr + segs[i]->p_filesz);
data_addr = mapbase + (data_vaddr - base_vaddr);
- data_prot = protflags(segs[i]->p_flags);
+ data_prot = convert_prot(segs[i]->p_flags);
+ data_flags = convert_flags(segs[i]->p_flags) | MAP_FIXED;
/* Do not call mmap on the first segment - this is redundant */
if (i && mmap(data_addr, data_vlimit - data_vaddr, data_prot,
- MAP_PRIVATE|MAP_FIXED, fd, data_offset) == (caddr_t) -1) {
+ data_flags, fd, data_offset) == (caddr_t) -1) {
_rtld_error("%s: mmap of data failed: %s", path, strerror(errno));
return NULL;
}
@@ -315,7 +318,7 @@ obj_new(void)
* flags for MMAP.
*/
static int
-protflags(int elfflags)
+convert_prot(int elfflags)
{
int prot = 0;
if (elfflags & PF_R)
@@ -326,3 +329,17 @@ protflags(int elfflags)
prot |= PROT_EXEC;
return prot;
}
+
+static int
+convert_flags(int elfflags)
+{
+ int flags = MAP_PRIVATE; /* All mappings are private */
+
+ /*
+ * Readonly mappings are marked "MAP_NOCORE", because they can be
+ * reconstructed by a debugger.
+ */
+ if (!(elfflags & PF_W))
+ flags |= MAP_NOCORE;
+ return flags;
+}
diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c
index 27bcfbe..44d4bf0 100644
--- a/sys/kern/imgact_elf.c
+++ b/sys/kern/imgact_elf.c
@@ -87,6 +87,9 @@ SYSCTL_INT(_debug, OID_AUTO, elf32_trace, CTLFLAG_RW, &elf_trace, 0, "");
#else
SYSCTL_INT(_debug, OID_AUTO, elf64_trace, CTLFLAG_RW, &elf_trace, 0, "");
#endif
+static int elf_legacy_coredump = 0;
+SYSCTL_INT(_debug, OID_AUTO, elf_legacy_coredump, CTLFLAG_RW,
+ &elf_legacy_coredump, 0, "");
static Elf_Brandinfo *elf_brand_list[MAX_BRANDS];
extern int fallback_elf_brand;
@@ -349,7 +352,7 @@ __elfN(load_section)(struct proc *p, struct vmspace *vmspace,
{
size_t map_len;
vm_offset_t map_addr;
- int error, rv;
+ int error, rv, cow;
size_t copy_len;
vm_offset_t file_addr;
vm_offset_t data_buf = 0;
@@ -392,6 +395,11 @@ __elfN(load_section)(struct proc *p, struct vmspace *vmspace,
if (map_len != 0) {
vm_object_reference(object);
+
+ /* cow flags: don't dump readonly sections in core */
+ cow = MAP_COPY_ON_WRITE | MAP_PREFAULT |
+ (prot & VM_PROT_WRITE ? 0 : MAP_DISABLE_COREDUMP);
+
rv = __elfN(map_insert)(&vmspace->vm_map,
object,
file_addr, /* file offset */
@@ -399,7 +407,7 @@ __elfN(load_section)(struct proc *p, struct vmspace *vmspace,
map_addr + map_len,/* virtual end */
prot,
VM_PROT_ALL,
- MAP_COPY_ON_WRITE | MAP_PREFAULT);
+ cow);
if (rv != KERN_SUCCESS) {
vm_object_deallocate(object);
return (EINVAL);
@@ -1042,17 +1050,29 @@ each_writable_segment(p, func, closure)
entry = entry->next) {
vm_object_t obj;
- if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) ||
- (entry->protection & (VM_PROT_READ|VM_PROT_WRITE)) !=
- (VM_PROT_READ|VM_PROT_WRITE))
- continue;
+ /*
+ * Don't dump inaccessible mappings, deal with legacy
+ * coredump mode.
+ *
+ * Note that read-only segments related to the elf binary
+ * are marked MAP_ENTRY_NOCOREDUMP now so we no longer
+ * need to arbitrarily ignore such segments.
+ */
+ if (elf_legacy_coredump) {
+ if ((entry->protection & VM_PROT_RW) != VM_PROT_RW)
+ continue;
+ } else {
+ if ((entry->protection & VM_PROT_ALL) == 0)
+ continue;
+ }
/*
- ** Dont include memory segment in the coredump if
- ** MAP_NOCORE is set in mmap(2) or MADV_NOCORE in
- ** madvise(2).
- */
- if (entry->eflags & MAP_ENTRY_NOCOREDUMP)
+ * Dont include memory segment in the coredump if
+ * MAP_NOCORE is set in mmap(2) or MADV_NOCORE in
+ * madvise(2). Do not dump submaps (i.e. parts of the
+ * kernel map).
+ */
+ if (entry->eflags & (MAP_ENTRY_NOCOREDUMP|MAP_ENTRY_IS_SUB_MAP))
continue;
if ((obj = entry->object.vm_object) == NULL)
diff --git a/sys/vm/vm.h b/sys/vm/vm.h
index ffbcd48..55818ef 100644
--- a/sys/vm/vm.h
+++ b/sys/vm/vm.h
@@ -81,6 +81,7 @@ typedef u_char vm_prot_t; /* protection codes */
#define VM_PROT_OVERRIDE_WRITE ((vm_prot_t) 0x08) /* copy-on-write */
#define VM_PROT_ALL (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)
+#define VM_PROT_RW (VM_PROT_READ|VM_PROT_WRITE)
#define VM_PROT_DEFAULT VM_PROT_ALL
union vm_map_object;
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