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From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: [2.6.25-rc2-mm1][2.6.25-rc3] Remove argv_len from struct linux_binprm
Date: Mon, 25 Feb 2008 09:55:04 +0900	[thread overview]
Message-ID: <200802250055.m1P0t4MX060531@www262.sakura.ne.jp> (raw)

I noticed that 2.6.24.2 calculates bprm->argv_len at do_execve().
But it doesn't update bprm->argv_len after
"remove_arg_zero() + copy_strings_kernel()" at load_script() etc.

audit_bprm() is called from search_binary_handler()
and search_binary_handler() is called from load_script() etc.
Thus, I think the condition check

  if (bprm->argv_len > (audit_argv_kb << 10))
          return -E2BIG;

in audit_bprm() might return wrong result
when strlen(removed_arg) != strlen(spliced_args).
Why not update bprm->argv_len at load_script() etc. ?


By the way, 2.6.25-rc3 seems to not doing the condition check.
Is the field bprm->argv_len no longer needed?

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 fs/exec.c               |    3 ---
 include/linux/binfmts.h |    1 -
 2 files changed, 4 deletions(-)

--- linux-2.6.25-rc3.orig/fs/exec.c
+++ linux-2.6.25-rc3/fs/exec.c
@@ -1274,7 +1274,6 @@ int do_execve(char * filename,
 {
 	struct linux_binprm *bprm;
 	struct file *file;
-	unsigned long env_p;
 	int retval;
 
 	retval = -ENOMEM;
@@ -1322,11 +1321,9 @@ int do_execve(char * filename,
 	if (retval < 0)
 		goto out;
 
-	env_p = bprm->p;
 	retval = copy_strings(bprm->argc, argv, bprm);
 	if (retval < 0)
 		goto out;
-	bprm->argv_len = env_p - bprm->p;
 
 	retval = search_binary_handler(bprm,regs);
 	if (retval >= 0) {
--- linux-2.6.25-rc3.orig/include/linux/binfmts.h
+++ linux-2.6.25-rc3/include/linux/binfmts.h
@@ -48,7 +48,6 @@ struct linux_binprm{
 	unsigned interp_flags;
 	unsigned interp_data;
 	unsigned long loader, exec;
-	unsigned long argv_len;
 };
 
 #define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0

                 reply	other threads:[~2008-02-25  0:55 UTC|newest]

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