Re: [Patch 3/9] fs/compat.c: fix resource leaks and wrong goto's

Al Viro
2008-05-10T20:35:55Z

On Sat, May 10, 2008 at 08:21:11PM +0100, Al Viro wrote:
> On Thu, May 08, 2008 at 09:52:28PM +0800, WANG Cong wrote:
> > Use free_arg_pages() to free the pages allocated by copy_strings_kernel()
> > on failure. And fix some related wrong goto pathes.
>
> Kinda; free_arg_pages() is needed here, but there's no need to mess with
> goto - just put it under out:
>
> Note that it's essentially just a part of freeing bprm; it's _not_ a "clean
> collected strings, so that we could add new ones".

FWIW, I'd suggest this:

diff --git a/fs/compat.c b/fs/compat.c
index 332a869..ed43e17 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1405,7 +1405,7 @@ int compat_do_execve(char * filename,
/* execve success */
security_bprm_free(bprm);
acct_update_integrals(current);
- kfree(bprm);
+ free_bprm(bprm);
return retval;
}

@@ -1424,7 +1424,7 @@ out_file:
}

out_kfree:
- kfree(bprm);
+ free_bprm(bprm);

out_ret:
return retval;
diff --git a/fs/exec.c b/fs/exec.c
index aeaa979..ad545b0 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1251,6 +1251,12 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)

EXPORT_SYMBOL(search_binary_handler);

+void free_bprm(struct linux_binprm *bprm)
+{
+ free_arg_pages(bprm);
+ kfree(bprm);
+}
+
/*
* sys_execve() executes a new program.
*/
@@ -1320,17 +1326,15 @@ int do_execve(char * filename,
retval = search_binary_handler(bprm,regs);
if (retval >= 0) {
/* execve success */
- free_arg_pages(bprm);
security_bprm_free(bprm);
acct_update_integrals(current);
- kfree(bprm);
+ free_bprm(bprm);
if (displaced)
put_files_struct(displaced);
return retval;
}

out:
- free_arg_pages(bprm);
if (bprm->security)
security_bprm_free(bprm);

diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index b512e48..c2f7fba 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -99,6 +99,7 @@ extern int copy_strings_kernel(int argc,char ** argv,struct linux_binprm *bprm);
extern void compute_creds(struct linux_binprm *binprm);
extern int do_coredump(long signr, int exit_code, struct pt_regs * regs);
extern int set_binfmt(struct linux_binfmt *new);
+extern void free_bprm(struct linux_binfmt *);

#endif /* __KERNEL__ */
#endif /* _LINUX_BINFMTS_H */