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exec: move allow_write_access/fput to exec_binprm() 

When search_binary_handler() succeeds it does allow_write_access() and
fput(), then it clears bprm->file to ensure the caller will not do the
same.

We can simply move this code to exec_binprm() which is called only once.
In fact we could move this to free_bprm() and remove the same code in
do_execve_common's error path.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Zach Levis <zml@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2013-09-11 14:24:41 -07:00 committed by Linus Torvalds
parent 9beb266f2d
commit 52f14282bb
1 changed files with 6 additions and 4 deletions
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10
fs/exec.c
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@ -1400,10 +1400,6 @@ int search_binary_handler(struct linux_binprm *bprm)
bprm->recursion_depth--;
if (retval >= 0) {
put_binfmt(fmt);
allow_write_access(bprm->file);
if (bprm->file)
fput(bprm->file);
bprm->file = NULL;
return retval;
}
read_lock(&binfmt_lock);
@ -1455,6 +1451,12 @@ static int exec_binprm(struct linux_binprm *bprm)
ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
current->did_exec = 1;
proc_exec_connector(current);
if (bprm->file) {
allow_write_access(bprm->file);
fput(bprm->file);
bprm->file = NULL; /* to catch use-after-free */
}
}
return ret;