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[Dle-develop] [PATCH -tip 1/3] Pass mm->flags to binfmt core_dump for bitflag consistency
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From: Masami H. <mhi...@re...> - 2009-11-13 22:53:38
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Pass mm->flags to binfmt core_dump for bitflag consistency.
Since mm->flags bit flags is not protected by locks, it will be
changed while dumping core. This patch copies mm->flags to a
mm_flags local variable at the beginning of do_coredump() and
use it while dumping. mm_flags also includes dump_filter which
filters elf sections from core file in elf_core_dump().
So, this patch also passes mm_flags to each binfmt->core_dump().
Signed-off-by: Masami Hiramatsu <mhi...@re...>
Cc: Hidehiro Kawai <hid...@hi...>
Cc: Andrew Morton <ak...@li...>
Cc: Oleg Nesterov <ol...@re...>
Cc: Roland McGrath <ro...@re...>
---
fs/binfmt_aout.c | 4 ++--
fs/binfmt_elf.c | 12 ++----------
fs/binfmt_elf_fdpic.c | 13 +++----------
fs/binfmt_flat.c | 4 ++--
fs/binfmt_som.c | 2 +-
fs/exec.c | 14 ++++++++++----
include/linux/binfmts.h | 2 +-
7 files changed, 21 insertions(+), 30 deletions(-)
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index b639dcf..ef1d4aa 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -32,7 +32,7 @@
static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
static int load_aout_library(struct file*);
-static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
+static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit, unsigned long mm_flags);
static struct linux_binfmt aout_format = {
.module = THIS_MODULE,
@@ -89,7 +89,7 @@ if (file->f_op->llseek) { \
* dumping of the process results in another error..
*/
-static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
+static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit, unsigned long mm_flags)
{
mm_segment_t fs;
int has_dumped = 0;
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index b9b3bb5..dd7256c 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -45,7 +45,7 @@ static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
* don't even try.
*/
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
-static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
+static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit, unsigned long mm_flags);
#else
#define elf_core_dump NULL
#endif
@@ -1906,7 +1906,7 @@ static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
* and then they are actually written out. If we run out of core limit
* we just truncate.
*/
-static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
+static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit, unsigned long mm_flags)
{
int has_dumped = 0;
mm_segment_t fs;
@@ -1915,7 +1915,6 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, un
struct vm_area_struct *vma, *gate_vma;
struct elfhdr *elf = NULL;
loff_t offset = 0, dataoff, foffset;
- unsigned long mm_flags;
struct elf_note_info info;
/*
@@ -1980,13 +1979,6 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, un
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
- /*
- * We must use the same mm->flags while dumping core to avoid
- * inconsistency between the program headers and bodies, otherwise an
- * unusable core file can be generated.
- */
- mm_flags = current->mm->flags;
-
/* Write program headers for segments dump */
for (vma = first_vma(current, gate_vma); vma != NULL;
vma = next_vma(vma, gate_vma)) {
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 38502c6..8af3633 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -76,7 +76,7 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
struct file *, struct mm_struct *);
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
-static int elf_fdpic_core_dump(long, struct pt_regs *, struct file *, unsigned long limit);
+static int elf_fdpic_core_dump(long, struct pt_regs *, struct file *, unsigned long limit, unsigned long mm_flags);
#endif
static struct linux_binfmt elf_fdpic_format = {
@@ -1582,7 +1582,8 @@ static int elf_fdpic_dump_segments(struct file *file, size_t *size,
* we just truncate.
*/
static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
- struct file *file, unsigned long limit)
+ struct file *file, unsigned long limit,
+ unsigned long mm_flags)
{
#define NUM_NOTES 6
int has_dumped = 0;
@@ -1605,7 +1606,6 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
#endif
int thread_status_size = 0;
elf_addr_t *auxv;
- unsigned long mm_flags;
/*
* We no longer stop all VM operations.
@@ -1736,13 +1736,6 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
/* Page-align dumped data */
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
- /*
- * We must use the same mm->flags while dumping core to avoid
- * inconsistency between the program headers and bodies, otherwise an
- * unusable core file can be generated.
- */
- mm_flags = current->mm->flags;
-
/* write program headers for segments dump */
for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
struct elf_phdr phdr;
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index a279665..6477678 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -87,7 +87,7 @@ static int load_flat_shared_library(int id, struct lib_info *p);
#endif
static int load_flat_binary(struct linux_binprm *, struct pt_regs * regs);
-static int flat_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
+static int flat_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit, unsigned long mm_flags);
static struct linux_binfmt flat_format = {
.module = THIS_MODULE,
@@ -102,7 +102,7 @@ static struct linux_binfmt flat_format = {
* Currently only a stub-function.
*/
-static int flat_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
+static int flat_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit, unsigned long mm_flags)
{
printk("Process %s:%d received signr %d and should have core dumped\n",
current->comm, current->pid, (int) signr);
diff --git a/fs/binfmt_som.c b/fs/binfmt_som.c
index eff74b9..983c01d 100644
--- a/fs/binfmt_som.c
+++ b/fs/binfmt_som.c
@@ -43,7 +43,7 @@ static int load_som_library(struct file *);
* don't even try.
*/
#if 0
-static int som_core_dump(long signr, struct pt_regs *regs, unsigned long limit);
+static int som_core_dump(long signr, struct pt_regs *regs, unsigned long limit, unsigned long mm_flags);
#else
#define som_core_dump NULL
#endif
diff --git a/fs/exec.c b/fs/exec.c
index ba112bd..dc418e3 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1722,7 +1722,7 @@ int get_dumpable(struct mm_struct *mm)
{
int ret;
- ret = mm->flags & 0x3;
+ ret = mm->flags & MMF_DUMPABLE_MASK;
return (ret >= 2) ? 2 : ret;
}
@@ -1754,6 +1754,12 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
struct core_state core_state;
char corename[CORENAME_MAX_SIZE + 1];
struct mm_struct *mm = current->mm;
+ /*
+ * We must use the same mm->flags while dumping core to avoid
+ * inconsistency of bit flags, since this flag is not protected
+ * by any locks.
+ */
+ unsigned long mm_flags = mm->flags;
struct linux_binfmt * binfmt;
struct inode * inode;
struct file * file;
@@ -1784,7 +1790,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
/*
* If another thread got here first, or we are not dumpable, bail out.
*/
- if (mm->core_state || !get_dumpable(mm)) {
+ if (mm->core_state || !(mm_flags & MMF_DUMPABLE_MASK)) {
up_write(&mm->mmap_sem);
put_cred(cred);
goto fail;
@@ -1795,7 +1801,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
* process nor do we know its entire history. We only know it
* was tainted so we dump it as root in mode 2.
*/
- if (get_dumpable(mm) == 2) { /* Setuid core dump mode */
+ if (mm_flags & (1 << MMF_DUMP_SECURELY)) { /* Setuid core dump mode */
flag = O_EXCL; /* Stop rewrite attacks */
cred->fsuid = 0; /* Dump root private */
}
@@ -1901,7 +1907,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0)
goto close_fail;
- retval = binfmt->core_dump(signr, regs, file, core_limit);
+ retval = binfmt->core_dump(signr, regs, file, core_limit, mm_flags);
if (retval)
current->signal->group_exit_code |= 0x80;
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index aece486..6e65c31 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -77,7 +77,7 @@ struct linux_binfmt {
struct module *module;
int (*load_binary)(struct linux_binprm *, struct pt_regs * regs);
int (*load_shlib)(struct file *);
- int (*core_dump)(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
+ int (*core_dump)(long signr, struct pt_regs *regs, struct file *file, unsigned long limit, unsigned long mm_flags);
unsigned long min_coredump; /* minimal dump size */
int hasvdso;
};
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhi...@re...
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