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Subject[PATCH v3 07/10] mm: use mm->exe_file instead of first VM_EXECUTABLE vma->vm_file
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Some security modules and oprofile still uses VM_EXECUTABLE for retrieving
task's executable file, after this patch they will use mm->exe_file directly.
mm->exe_file protected with mm->mmap_sem, so locking stays the same.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Chris Metcalf <cmetcalf@tilera.com> #arch/tile
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> #security/tomoyo
Cc: Robert Richter <robert.richter@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: James Morris <james.l.morris@oracle.com>
Cc: linux-security-module@vger.kernel.org
Cc: oprofile-list@lists.sf.net
---
arch/powerpc/oprofile/cell/spu_task_sync.c | 15 ++++-----------
arch/tile/mm/elf.c | 19 +++++++------------
drivers/oprofile/buffer_sync.c | 17 +++--------------
kernel/auditsc.c | 13 ++-----------
kernel/fork.c | 3 +--
security/tomoyo/util.c | 9 ++-------
6 files changed, 19 insertions(+), 57 deletions(-)
diff --git a/arch/powerpc/oprofile/cell/spu_task_sync.c b/arch/powerpc/oprofile/cell/spu_task_sync.c
index 642fca1..28f1af2 100644
--- a/arch/powerpc/oprofile/cell/spu_task_sync.c
+++ b/arch/powerpc/oprofile/cell/spu_task_sync.c
@@ -304,7 +304,7 @@ static inline unsigned long fast_get_dcookie(struct path *path)
return cookie;
}

-/* Look up the dcookie for the task's first VM_EXECUTABLE mapping,
+/* Look up the dcookie for the task's mm->exe_file,
* which corresponds loosely to "application name". Also, determine
* the offset for the SPU ELF object. If computed offset is
* non-zero, it implies an embedded SPU object; otherwise, it's a
@@ -321,7 +321,6 @@ get_exec_dcookie_and_offset(struct spu *spu, unsigned int *offsetp,
{
unsigned long app_cookie = 0;
unsigned int my_offset = 0;
- struct file *app = NULL;
struct vm_area_struct *vma;
struct mm_struct *mm = spu->mm;

@@ -330,16 +329,10 @@ get_exec_dcookie_and_offset(struct spu *spu, unsigned int *offsetp,

down_read(&mm->mmap_sem);

- for (vma = mm->mmap; vma; vma = vma->vm_next) {
- if (!vma->vm_file)
- continue;
- if (!(vma->vm_flags & VM_EXECUTABLE))
- continue;
- app_cookie = fast_get_dcookie(&vma->vm_file->f_path);
+ if (mm->exe_file) {
+ app_cookie = fast_get_dcookie(&mm->exe_file->f_path);
pr_debug("got dcookie for %s\n",
- vma->vm_file->f_dentry->d_name.name);
- app = vma->vm_file;
- break;
+ mm->exe_file->f_dentry->d_name.name);
}

for (vma = mm->mmap; vma; vma = vma->vm_next) {
diff --git a/arch/tile/mm/elf.c b/arch/tile/mm/elf.c
index 758b603..3cfa98b 100644
--- a/arch/tile/mm/elf.c
+++ b/arch/tile/mm/elf.c
@@ -36,19 +36,14 @@ static void sim_notify_exec(const char *binary_name)
} while (c);
}

-static int notify_exec(void)
+static int notify_exec(struct mm_struct *mm)
{
int retval = 0; /* failure */
- struct vm_area_struct *vma = current->mm->mmap;
- while (vma) {
- if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file)
- break;
- vma = vma->vm_next;
- }
- if (vma) {
+
+ if (mm->exe_file) {
char *buf = (char *) __get_free_page(GFP_KERNEL);
if (buf) {
- char *path = d_path(&vma->vm_file->f_path,
+ char *path = d_path(&mm->exe_file->f_path,
buf, PAGE_SIZE);
if (!IS_ERR(path)) {
sim_notify_exec(path);
@@ -106,16 +101,16 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
unsigned long vdso_base;
int retval = 0;

+ down_write(&mm->mmap_sem);
+
/*
* Notify the simulator that an exec just occurred.
* If we can't find the filename of the mapping, just use
* whatever was passed as the linux_binprm filename.
*/
- if (!notify_exec())
+ if (!notify_exec(mm))
sim_notify_exec(bprm->filename);

- down_write(&mm->mmap_sem);
-
/*
* MAYWRITE to allow gdb to COW and set breakpoints
*/
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index f34b5b2..d93b2b6 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -216,7 +216,7 @@ static inline unsigned long fast_get_dcookie(struct path *path)
}


-/* Look up the dcookie for the task's first VM_EXECUTABLE mapping,
+/* Look up the dcookie for the task's mm->exe_file,
* which corresponds loosely to "application name". This is
* not strictly necessary but allows oprofile to associate
* shared-library samples with particular applications
@@ -224,21 +224,10 @@ static inline unsigned long fast_get_dcookie(struct path *path)
static unsigned long get_exec_dcookie(struct mm_struct *mm)
{
unsigned long cookie = NO_COOKIE;
- struct vm_area_struct *vma;
-
- if (!mm)
- goto out;

- for (vma = mm->mmap; vma; vma = vma->vm_next) {
- if (!vma->vm_file)
- continue;
- if (!(vma->vm_flags & VM_EXECUTABLE))
- continue;
- cookie = fast_get_dcookie(&vma->vm_file->f_path);
- break;
- }
+ if (mm && mm->exe_file)
+ cookie = fast_get_dcookie(&mm->exe_file->f_path);

-out:
return cookie;
}

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4b96415..31cf885 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1158,7 +1158,6 @@ static void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk
{
char name[sizeof(tsk->comm)];
struct mm_struct *mm = tsk->mm;
- struct vm_area_struct *vma;

/* tsk == current */

@@ -1168,16 +1167,8 @@ static void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk

if (mm) {
down_read(&mm->mmap_sem);
- vma = mm->mmap;
- while (vma) {
- if ((vma->vm_flags & VM_EXECUTABLE) &&
- vma->vm_file) {
- audit_log_d_path(ab, " exe=",
- &vma->vm_file->f_path);
- break;
- }
- vma = vma->vm_next;
- }
+ if (mm->exe_file)
+ audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
up_read(&mm->mmap_sem);
}
audit_log_task_context(ab);
diff --git a/kernel/fork.c b/kernel/fork.c
index 8efac1f..bd5c4c5 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -659,8 +659,7 @@ struct file *get_mm_exe_file(struct mm_struct *mm)
{
struct file *exe_file;

- /* We need mmap_sem to protect against races with removal of
- * VM_EXECUTABLE vmas */
+ /* We need mmap_sem to protect against races with removal of exe_file */
down_read(&mm->mmap_sem);
exe_file = mm->exe_file;
if (exe_file)
diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c
index 867558c..2952ba5 100644
--- a/security/tomoyo/util.c
+++ b/security/tomoyo/util.c
@@ -949,18 +949,13 @@ bool tomoyo_path_matches_pattern(const struct tomoyo_path_info *filename,
const char *tomoyo_get_exe(void)
{
struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma;
const char *cp = NULL;

if (!mm)
return NULL;
down_read(&mm->mmap_sem);
- for (vma = mm->mmap; vma; vma = vma->vm_next) {
- if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file) {
- cp = tomoyo_realpath_from_path(&vma->vm_file->f_path);
- break;
- }
- }
+ if (mm->exe_file)
+ cp = tomoyo_realpath_from_path(&mm->exe_file->f_path);
up_read(&mm->mmap_sem);
return cp;
}


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