From 131b2f9f1214f338f0bf7c0d9760019f2b1d0c20 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 11 Sep 2013 14:24:39 -0700 Subject: [PATCH] exec: kill "int depth" in search_binary_handler() Nobody except search_binary_handler() should touch ->recursion_depth, "int depth" buys nothing but complicates the code, kill it. Probably we should also kill "fn" and the !NULL check, ->load_binary should be always defined. And it can not go away after read_unlock() or this code is buggy anyway. Signed-off-by: Oleg Nesterov Acked-by: Kees Cook Cc: Al Viro Cc: Evgeniy Polyakov Cc: Zach Levis Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/exec.c | 9 ++++----- include/linux/binfmts.h | 2 +- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 4d95b4709ea0..b6e35ec818a2 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1370,12 +1370,11 @@ EXPORT_SYMBOL(remove_arg_zero); */ int search_binary_handler(struct linux_binprm *bprm) { - unsigned int depth = bprm->recursion_depth; - int try,retval; + int try, retval; struct linux_binfmt *fmt; /* This allows 4 levels of binfmt rewrites before failing hard. */ - if (depth > 5) + if (bprm->recursion_depth > 5) return -ELOOP; retval = security_bprm_check(bprm); @@ -1396,9 +1395,9 @@ int search_binary_handler(struct linux_binprm *bprm) if (!try_module_get(fmt->module)) continue; read_unlock(&binfmt_lock); - bprm->recursion_depth = depth + 1; + bprm->recursion_depth++; retval = fn(bprm); - bprm->recursion_depth = depth; + bprm->recursion_depth--; if (retval >= 0) { put_binfmt(fmt); allow_write_access(bprm->file); diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index 70cf138690e9..e8112ae50531 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -31,7 +31,7 @@ struct linux_binprm { #ifdef __alpha__ unsigned int taso:1; #endif - unsigned int recursion_depth; + unsigned int recursion_depth; /* only for search_binary_handler() */ struct file * file; struct cred *cred; /* new credentials */ int unsafe; /* how unsafe this exec is (mask of LSM_UNSAFE_*) */ -- 2.20.1