[PATCH v5 04/15] elf_fdpic_transfer_args_to_stack(): make it generic
From: Nicolas Pitre <hidden>
Date: 2016-07-24 15:30:40
Also in:
linux-fsdevel, lkml
Subsystem:
exec & binfmt api, elf, filesystems (vfs and infrastructure), the rest · Maintainers:
Kees Cook, Alexander Viro, Christian Brauner, Linus Torvalds
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 <redacted> Reviewed-by: Greg Ungerer <gerg@linux-m68k.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);
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2.7.4