diff mbox series

[5/5] exec: Move the call of prepare_binprm into search_binary_handler

Message ID 873688zygz.fsf_-_@x220.int.ebiederm.org (mailing list archive)
State New, archived
Headers show
Series exec: Control flow simplifications | expand

Commit Message

Eric W. Biederman May 9, 2020, 7:42 p.m. UTC 
The code in prepare_binary_handler needs to be run every time
search_binary_handler is called so move the call into search_binary_handler
itself to make the code simpler and easier to understand.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/alpha/kernel/binfmt_loader.c |  3 ---
 fs/binfmt_em86.c                  |  5 -----
 fs/binfmt_misc.c                  |  4 ----
 fs/binfmt_script.c                |  3 ---
 fs/exec.c                         | 12 +++++-------
 include/linux/binfmts.h           |  1 -
 6 files changed, 5 insertions(+), 23 deletions(-)

Comments

Kees Cook May 11, 2020, 10:24 p.m. UTC | #1 
On Sat, May 09, 2020 at 02:42:52PM -0500, Eric W. Biederman wrote:
> 
> The code in prepare_binary_handler needs to be run every time
> search_binary_handler is called so move the call into search_binary_handler
> itself to make the code simpler and easier to understand.
> 
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Yes, nice. :) I don't see any ordering dependencies here. The only thing
I see is a potential for more "work done by kernel before bailing" in
the sense that the arg copying will be performed before we check the
kernel_read() result. I struggle to see how that might be a problem,
and this get us to fewer exec.c exports. Yay!

Reviewed-by: Kees Cook <keescook@chromium.org>
diff mbox series

Patch

diff --git a/arch/alpha/kernel/binfmt_loader.c b/arch/alpha/kernel/binfmt_loader.c
index a90c8b1d5498..ec7b26e4b81a 100644
--- a/arch/alpha/kernel/binfmt_loader.c
+++ b/arch/alpha/kernel/binfmt_loader.c
@@ -35,9 +35,6 @@  static int load_binary(struct linux_binprm *bprm)
 
 	bprm->file = file;
 	bprm->loader = loader;
-	retval = prepare_binprm(bprm);
-	if (retval < 0)
-		return retval;
 	return 1; /* Search for the interpreter */
 }
 
diff --git a/fs/binfmt_em86.c b/fs/binfmt_em86.c
index a9b9ac7f9bb0..2726bfb832b2 100644
--- a/fs/binfmt_em86.c
+++ b/fs/binfmt_em86.c
@@ -90,11 +90,6 @@  static int load_em86(struct linux_binprm *bprm)
 		return PTR_ERR(file);
 
 	bprm->file = file;
-
-	retval = prepare_binprm(bprm);
-	if (retval < 0)
-		return retval;
-
 	return 1; /* Search for the interpreter */
 }
 
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 16bfafd2671d..6b5e67eed65e 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -221,10 +221,6 @@  static int load_misc_binary(struct linux_binprm *bprm)
 	if (fmt->flags & MISC_FMT_CREDENTIALS)
 		bprm->preserve_creds = 1;
 
-	retval = prepare_binprm(bprm);
-	if (retval < 0)
-		goto error;
-
 	retval = 1; /* Search for the interpreter */
 ret:
 	dput(fmt->dentry);
diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c
index 76a05696d376..ed4607c7095e 100644
--- a/fs/binfmt_script.c
+++ b/fs/binfmt_script.c
@@ -143,9 +143,6 @@  static int load_script(struct linux_binprm *bprm)
 		return PTR_ERR(file);
 
 	bprm->file = file;
-	retval = prepare_binprm(bprm);
-	if (retval < 0)
-		return retval;
 	return 1; /* Search for the interpreter */
 }
 
diff --git a/fs/exec.c b/fs/exec.c
index 01dbeb025c46..206f18120073 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1628,7 +1628,7 @@  static void bprm_fill_uid(struct linux_binprm *bprm)
  *
  * This may be called multiple times for binary chains (scripts for example).
  */
-int prepare_binprm(struct linux_binprm *bprm)
+static int prepare_binprm(struct linux_binprm *bprm)
 {
 	loff_t pos = 0;
 
@@ -1647,8 +1647,6 @@  int prepare_binprm(struct linux_binprm *bprm)
 	return kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, &pos);
 }
 
-EXPORT_SYMBOL(prepare_binprm);
-
 /*
  * Arguments are '\0' separated strings found at the location bprm->p
  * points to; chop off the first by relocating brpm->p to right after
@@ -1700,6 +1698,10 @@  static int search_binary_handler(struct linux_binprm *bprm)
 	struct linux_binfmt *fmt;
 	int retval;
 
+	retval = prepare_binprm(bprm);
+	if (retval < 0)
+		return retval;
+
 	retval = security_bprm_check(bprm);
 	if (retval)
 		return retval;
@@ -1859,10 +1861,6 @@  static int __do_execve_file(int fd, struct filename *filename,
 	if (retval)
 		goto out;
 
-	retval = prepare_binprm(bprm);
-	if (retval < 0)
-		goto out;
-
 	retval = copy_strings_kernel(1, &bprm->filename, bprm);
 	if (retval < 0)
 		goto out;
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index cb016f001e7a..0748afca40cb 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -117,7 +117,6 @@  static inline void insert_binfmt(struct linux_binfmt *fmt)
 
 extern void unregister_binfmt(struct linux_binfmt *);
 
-extern int prepare_binprm(struct linux_binprm *);
 extern int __must_check remove_arg_zero(struct linux_binprm *);
 extern int begin_new_exec(struct linux_binprm * bprm);
 extern void setup_new_exec(struct linux_binprm * bprm);