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Date: Sun, 17 Jul 2016 23:31:48 -0400
From: Nicolas Pitre <nicolas.pitre@...aro.org>
To: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
David Howells <dhowells@...hat.com>,
Greg Ungerer <gerg@...ux-m68k.org>
Subject: [PATCH v2 02/10] elf_fdpic_transfer_args_to_stack(): make it generic
This copying of arguments and environment is common to both NOMMU
binary formats we support. Let's make the elf_fdpic version available
to the flat format as well.
While at it, improve the code a bit not to copy below the actual
data area.
Signed-off-by: Nicolas Pitre <nico@...aro.org>
---
fs/binfmt_elf_fdpic.c | 38 ++------------------------------------
fs/exec.c | 33 +++++++++++++++++++++++++++++++++
include/linux/binfmts.h | 2 ++
3 files changed, 37 insertions(+), 36 deletions(-)
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 203589311b..464a972e88 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -67,8 +67,6 @@ static int create_elf_fdpic_tables(struct linux_binprm *, struct mm_struct *,
struct elf_fdpic_params *);
#ifndef CONFIG_MMU
-static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *,
- unsigned long *);
static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
struct file *,
struct mm_struct *);
@@ -515,8 +513,9 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
sp = mm->start_stack;
/* stack the program arguments and environment */
- if (elf_fdpic_transfer_args_to_stack(bprm, &sp) < 0)
+ if (transfer_args_to_stack(bprm, &sp) < 0)
return -EFAULT;
+ sp &= ~15;
#endif
/*
@@ -711,39 +710,6 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm,
/*****************************************************************************/
/*
- * transfer the program arguments and environment from the holding pages onto
- * the stack
- */
-#ifndef CONFIG_MMU
-static int elf_fdpic_transfer_args_to_stack(struct linux_binprm *bprm,
- unsigned long *_sp)
-{
- unsigned long index, stop, sp;
- char *src;
- int ret = 0;
-
- stop = bprm->p >> PAGE_SHIFT;
- sp = *_sp;
-
- for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
- src = kmap(bprm->page[index]);
- sp -= PAGE_SIZE;
- if (copy_to_user((void *) sp, src, PAGE_SIZE) != 0)
- ret = -EFAULT;
- kunmap(bprm->page[index]);
- if (ret < 0)
- goto out;
- }
-
- *_sp = (*_sp - (MAX_ARG_PAGES * PAGE_SIZE - bprm->p)) & ~15;
-
-out:
- return ret;
-}
-#endif
-
-/*****************************************************************************/
-/*
* load the appropriate binary image (executable or interpreter) into memory
* - we assume no MMU is available
* - if no other PIC bits are set in params->hdr->e_flags
diff --git a/fs/exec.c b/fs/exec.c
index 887c1c955d..ef0df2f092 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -762,6 +762,39 @@ out_unlock:
}
EXPORT_SYMBOL(setup_arg_pages);
+#else
+
+/*
+ * Transfer the program arguments and environment from the holding pages
+ * onto the stack. The provided stack pointer is adjusted accordingly.
+ */
+int transfer_args_to_stack(struct linux_binprm *bprm,
+ unsigned long *sp_location)
+{
+ unsigned long index, stop, sp;
+ int ret = 0;
+
+ stop = bprm->p >> PAGE_SHIFT;
+ sp = *sp_location;
+
+ for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
+ unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0;
+ char *src = kmap(bprm->page[index]) + offset;
+ sp -= PAGE_SIZE - offset;
+ if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0)
+ ret = -EFAULT;
+ kunmap(bprm->page[index]);
+ if (ret)
+ goto out;
+ }
+
+ *sp_location = sp;
+
+out:
+ return ret;
+}
+EXPORT_SYMBOL(transfer_args_to_stack);
+
#endif /* CONFIG_MMU */
static struct file *do_open_execat(int fd, struct filename *name, int flags)
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index 314b3caa70..1303b570b1 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -113,6 +113,8 @@ extern int suid_dumpable;
extern int setup_arg_pages(struct linux_binprm * bprm,
unsigned long stack_top,
int executable_stack);
+extern int transfer_args_to_stack(struct linux_binprm *bprm,
+ unsigned long *sp_location);
extern int bprm_change_interp(char *interp, struct linux_binprm *bprm);
extern int copy_strings_kernel(int argc, const char *const *argv,
struct linux_binprm *bprm);
--
2.7.4
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