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authorOleg Nesterov <oleg@redhat.com>2013-09-11 14:24:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:59:05 -0700
commit52f14282bb0c3d3e5ba2a9eaacb12ff37a033e7e (patch)
treec0f02056772e53e294784388b4202e94271c46e6
parent9beb266f2d7e5362c5bb9f999255aa1af5318aef (diff)
downloadlinux-52f14282bb0c3d3e5ba2a9eaacb12ff37a033e7e.tar.gz
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>
-rw-r--r--fs/exec.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/exec.c b/fs/exec.c
index d51f7172832..a4cfd1d725e 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -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;