From 2cd50532ce5c798c029a39234ad7f48a174e15ec Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Wed, 23 Mar 2022 16:06:26 -0700 Subject: [PATCH] fat: use pointer to simple type in put_user() The put_user(val,ptr) macro wants a pointer to a simple type, but in fat_ioctl_filldir() the d_name field references an "array of chars". Be more accurate and explicitly give the pointer to the first character of the d_name[] array. I noticed that issue while trying to optimize the parisc put_user() macro and used an intermediate variable to store the pointer. In that case I got this error: In file included from include/linux/uaccess.h:11, from include/linux/compat.h:17, from fs/fat/dir.c:18: fs/fat/dir.c: In function `fat_ioctl_filldir': fs/fat/dir.c:725:33: error: invalid initializer 725 | if (put_user(0, d2->d_name) || \ | ^~ include/asm/uaccess.h:152:33: note: in definition of macro `__put_user' 152 | __typeof__(ptr) __ptr = ptr; \ | ^~~ fs/fat/dir.c:759:1: note: in expansion of macro `FAT_IOCTL_FILLDIR_FUNC' 759 | FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent) Andreas Schwab suggested to use __typeof__(&*(ptr)) __ptr = ptr; instead. This works, but nevertheless it's probably reasonable to fix the original caller too. Link: https://lkml.kernel.org/r/Ygo+A9MREmC1H3kr@p100 Signed-off-by: Helge Deller Acked-by: OGAWA Hirofumi Cc: David Laight Cc: Andreas Schwab Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fat/dir.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fat/dir.c b/fs/fat/dir.c index c4a2742..2498250 100644 --- a/fs/fat/dir.c +++ b/fs/fat/dir.c @@ -722,7 +722,7 @@ static int func(struct dir_context *ctx, const char *name, int name_len, \ if (name_len >= sizeof(d1->d_name)) \ name_len = sizeof(d1->d_name) - 1; \ \ - if (put_user(0, d2->d_name) || \ + if (put_user(0, &d2->d_name[0]) || \ put_user(0, &d2->d_reclen) || \ copy_to_user(d1->d_name, name, name_len) || \ put_user(0, d1->d_name + name_len) || \ -- 2.7.4