[PATCH v4 09/12] binfmt_flat: use clear_user() rather than memset() to clear .bss

From: Nicolas Pitre
Date: Wed Jul 20 2016 - 15:26:08 EST


This is needed on systems with a MMU.

Signed-off-by: Nicolas Pitre <nico@xxxxxxxxxx>
Reviewed-by: Greg Ungerer <gerg@xxxxxxxxxxxxxx>
---
fs/binfmt_flat.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 63756ca6a7..92c1530a2c 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -795,10 +795,11 @@ static int load_flat_file(struct linux_binprm *bprm,
flush_icache_range(start_code, end_code);

/* zero the BSS, BRK and stack areas */
- memset((void *)(datapos + data_len), 0, bss_len +
- (memp + memp_size - stack_len - /* end brk */
- libinfo->lib_list[id].start_brk) + /* start brk */
- stack_len);
+ if (clear_user((void __user *)(datapos + data_len), bss_len +
+ (memp + memp_size - stack_len - /* end brk */
+ libinfo->lib_list[id].start_brk) + /* start brk */
+ stack_len))
+ return -EFAULT;

return 0;
err:
--
2.7.4