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authorOleg Nesterov <oleg@redhat.com>2013-09-11 14:24:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:59:04 -0700
commit131b2f9f1214f338f0bf7c0d9760019f2b1d0c20 (patch)
treeb60a498414e259fe4e81f210378538f90ada9224
parent5d1baf3b63bfc8c709dc44df85ff1475c7ef489d (diff)
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 <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.c9
-rw-r--r--include/linux/binfmts.h2
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_*) */