Subject: + exec-move-allow_write_access-fput-to-exec_binprm.patch added to -mm tree
To: oleg@xxxxxxxxxx,keescook@xxxxxxxxxxxx,viro@xxxxxxxxxxxxxxxxxx,zbr@xxxxxxxxxxx,zml@xxxxxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 05 Aug 2013 13:45:11 -0700
The patch titled
Subject: exec: move allow_write_access/fput to exec_binprm()
has been added to the -mm tree. Its filename is
exec-move-allow_write_access-fput-to-exec_binprm.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/exec-move-allow_write_access-fput-to-exec_binprm.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/exec-move-allow_write_access-fput-to-exec_binprm.patch
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From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Evgeniy Polyakov <zbr@xxxxxxxxxxx>
Cc: Zach Levis <zml@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/exec.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff -puN fs/exec.c~exec-move-allow_write_access-fput-to-exec_binprm fs/exec.c
--- a/fs/exec.c~exec-move-allow_write_access-fput-to-exec_binprm
+++ a/fs/exec.c
@@ -1400,10 +1400,6 @@ int search_binary_handler(struct linux_b
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_binp
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;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
x86-get_unmapped_area-use-proper-mmap-base-for-bottom-up-direction.patch
include-linux-schedh-dont-use-task-pid-tgid-in-same_thread_group-has_group_leader_pid.patch
mm-mempolicy-turn-vma_set_policy-into-vma_dup_policy.patch
mm-shift-vm_grows-check-from-mmap_region-to-do_mmap_pgoff-v2.patch
mm-do_mmap_pgoff-cleanup-the-usage-of-file_inode.patch
mm-mmap_region-kill-correct_wcount-inode-use-allow_write_access.patch
kernel-wide-fix-missing-validations-on-__get-__put-__copy_to-__copy_from_user.patch
autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch
autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch
signals-eventpoll-set-saved_sigmask-at-the-start.patch
move-exit_task_namespaces-outside-of-exit_notify-fix.patch
exec-introduce-exec_binprm-for-depth-==-0-code.patch
exec-kill-int-depth-in-search_binary_handler.patch
exec-proc_exec_connector-should-be-called-only-once.patch
exec-move-allow_write_access-fput-to-exec_binprm.patch
exec-kill-load_binary-=-null-check-in-search_binary_handler.patch
exec-cleanup-the-config_modules-logic.patch
exec-dont-retry-if-request_module-fails.patch
exec-cleanup-the-error-handling-in-search_binary_handler.patch
linux-next.patch
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