[PATCH v2 5/8] exec: Move the call of prepare_binprm into search_binary_handler

From: Eric W. Biederman
Date: Mon May 18 2020 - 20:36:02 EST



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@xxxxxxxxxxxx>
---
arch/alpha/kernel/binfmt_loader.c | 3 ---
fs/binfmt_em86.c | 4 ----
fs/binfmt_misc.c | 4 ----
fs/binfmt_script.c | 3 ---
fs/exec.c | 12 +++++-------
include/linux/binfmts.h | 1 -
6 files changed, 5 insertions(+), 22 deletions(-)

diff --git a/arch/alpha/kernel/binfmt_loader.c b/arch/alpha/kernel/binfmt_loader.c
index a8d0d6e06526..d712ba51d15a 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 search_binary_handler(bprm);
}

diff --git a/fs/binfmt_em86.c b/fs/binfmt_em86.c
index 466497860c62..cedde2341ade 100644
--- a/fs/binfmt_em86.c
+++ b/fs/binfmt_em86.c
@@ -91,10 +91,6 @@ static int load_em86(struct linux_binprm *bprm)

bprm->file = file;

- retval = prepare_binprm(bprm);
- if (retval < 0)
- return retval;
-
return search_binary_handler(bprm);
}

diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 264829745d6f..50a73afdf9b7 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 = search_binary_handler(bprm);
if (retval < 0)
goto error;
diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c
index e9e6a6f4a35f..8d718d8fd0fe 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 search_binary_handler(bprm);
}

diff --git a/fs/exec.c b/fs/exec.c
index 028e0e323af5..5fc458460e44 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1629,7 +1629,7 @@ 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;

@@ -1650,8 +1650,6 @@ 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
@@ -1707,6 +1705,10 @@ int search_binary_handler(struct linux_binprm *bprm)
if (bprm->recursion_depth > 5)
return -ELOOP;

+ retval = prepare_binprm(bprm);
+ if (retval < 0)
+ return retval;
+
retval = security_bprm_check(bprm);
if (retval)
return retval;
@@ -1864,10 +1866,6 @@ 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 dbb5614d62a2..8c7779d6bf19 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -116,7 +116,6 @@ 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 search_binary_handler(struct linux_binprm *);
extern int begin_new_exec(struct linux_binprm * bprm);
--
2.25.0